Re: filmscanners: Best solution for HD and images
on 11/14/01 5:11 AM, Charles Knox at [EMAIL PROTECTED] wrote: > At 12:35 AM 14/11/01 -0600, you wrote: >>> With two disks, you would be correct; but in this case, the two disks are >>> going to act as one, so both must be set to be masters. >> >> Right, but they are on separate IDE channels (channels 3 & 4) if I am >> understanding things correctly which is what lets them read and right >> simultaneously in parallel which is not the case if they were both on the >> same channel. I also do not think it is possible to have to master drives >> on the same channel so you cannot have the jumpers on both drives set for >> master drive if they are connected to the same cable and channel. The same >> RAID array using two IDE channels maybe. Am I understanding things >> correctly? >> >> > > I think if you are using two drives on each channel you'd need to set all > four to cable select? > > I have a two-drive Raid-0 setup on ports 3 & 4, attached to the end > connectors on UDMA cables and that's how they're configured -- if I add two > more drives configured the same way they'll be attached to the intermediate > connectors. > > The raid controller should then recognise them as a single drive just as it > does the primaries. > > I'm also of the opinion that two drives set to master on the same cable > would conflict -- that's what cable select (not recommended for > conventional IDE setups, BTW) is all about. > I was unable to find the tutorial I was remembering for LAURIE, so I will acquiesce. I meely answered what I thought to be true from a web article I had read. Jim Snyder
RE: filmscanners: Best solution for HD and images
At 12:35 AM 14/11/01 -0600, you wrote: >>With two disks, you would be correct; but in this case, the two disks are >>going to act as one, so both must be set to be masters. > >Right, but they are on separate IDE channels (channels 3 & 4) if I am >understanding things correctly which is what lets them read and right >simultaneously in parallel which is not the case if they were both on the >same channel. I also do not think it is possible to have to master drives >on the same channel so you cannot have the jumpers on both drives set for >master drive if they are connected to the same cable and channel. The same >RAID array using two IDE channels maybe. Am I understanding things >correctly? > > I think if you are using two drives on each channel you'd need to set all four to cable select? I have a two-drive Raid-0 setup on ports 3 & 4, attached to the end connectors on UDMA cables and that's how they're configured -- if I add two more drives configured the same way they'll be attached to the intermediate connectors. The raid controller should then recognise them as a single drive just as it does the primaries. I'm also of the opinion that two drives set to master on the same cable would conflict -- that's what cable select (not recommended for conventional IDE setups, BTW) is all about. Charles
RE: filmscanners: Best solution for HD and images
Lawrence, I don't appreciate personal attacks, I'm sure no one does. If you really need to personally attack me, please do so off list. I've never done so to you, and you should be adult enough to keep this kind of childish crap off the list. If you don't like a discussion, just delete it or learn to use filters. Austin > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Lawrence Smith > Sent: Wednesday, November 14, 2001 7:48 AM > To: filmscanners halftone.co.uk > Subject: Re: filmscanners: Best solution for HD and images > > > Blah, blah, blah > > > I thought this was a SCANNER list. Could we take this whole > thing off line. > It's clearly turned into another Austin Franklin platform for argument and > pedantry. I'm getting a blister on my DEL key finger > > Lawrence > > -- > Lawrence W. Smith Photography > http://www.lwsphoto.com > [EMAIL PROTECTED] > -- > >
Re: filmscanners: Best solution for HD and images
Blah, blah, blah I thought this was a SCANNER list. Could we take this whole thing off line. It's clearly turned into another Austin Franklin platform for argument and pedantry. I'm getting a blister on my DEL key finger Lawrence -- Lawrence W. Smith Photography http://www.lwsphoto.com [EMAIL PROTECTED] --
Re: filmscanners: Best solution for HD and images
This isn't true. The RAID controller or software does the work, and each channel has a master and a slave as normal. These days with 80-way IDE leads you might as well set both drives to cable select and let the cable decide though. [EMAIL PROTECTED] (Jim Snyder) wrote: > on 11/12/01 10:34 PM, LAURIE SOLOMON at [EMAIL PROTECTED] wrote: > > >> Actually, both must be set up on the same IDE channel as masters. > > > > How does one do that? I thought that you could only have one master > > device > > per channel; and it was the one that was connected to the end of the > > ribbon > > cable and had its jumper set for master. > > > With two disks, you would be correct; but in this case, the two disks > are > going to act as one, so both must be set to be masters. > > Jim Snyder > >
RE: filmscanners: Best solution for HD and images
>With two disks, you would be correct; but in this case, the two disks are >going to act as one, so both must be set to be masters. Right, but they are on separate IDE channels (channels 3 & 4) if I am understanding things correctly which is what lets them read and right simultaneously in parallel which is not the case if they were both on the same channel. I also do not think it is possible to have to master drives on the same channel so you cannot have the jumpers on both drives set for master drive if they are connected to the same cable and channel. The same RAID array using two IDE channels maybe. Am I understanding things correctly? -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Jim Snyder Sent: Tuesday, November 13, 2001 7:50 PM To: [EMAIL PROTECTED] Subject: Re: filmscanners: Best solution for HD and images on 11/12/01 10:34 PM, LAURIE SOLOMON at [EMAIL PROTECTED] wrote: >> Actually, both must be set up on the same IDE channel as masters. > > How does one do that? I thought that you could only have one master device > per channel; and it was the one that was connected to the end of the ribbon > cable and had its jumper set for master. > With two disks, you would be correct; but in this case, the two disks are going to act as one, so both must be set to be masters. Jim Snyder
Re: filmscanners: Best solution for HD and images
> FOR ALL THOSE A BIT BORED WITH THIS: > > You should know that not only do striped disks reduce reliability and hence > increase risk but they also increase severity. > i.e. any one drive of a multiple striped drive set failing WILL lose ALL of > your data. > > You should only use this arrangement where you keep very regular backups, > you use it largely as a scratch area or you can relatively easily recreate > the data. The increased performance benefits of a simple two drive Raid 0 array are very significant, in that one can usually expect the disk performance to double. This is a huge benefit to anyone working with large files, as would be most readers of this list. You'll lose all of your data whether a standalone drive or an array drive fails. It makes good sense to perform regular backups, regardless of the nature of the disk subsystem. Practically speaking, today's drives are quite reliable. You make it sound like a person is treading dangerous ground by running a striped array, which isn't the case at all. I'd agree that multiple drives do increase the odds of drive failure, but these days even IDE drives have a MTBF rating of 200,000 hrs, which is over 20 years of service life.
Re: filmscanners: Best solution for HD and images
on 11/13/01 1:01 AM, Austin Franklin at [EMAIL PROTECTED] wrote: > >> on 11/11/01 10:21 PM, Austin Franklin at [EMAIL PROTECTED] wrote: >> the limit of a 32bit PCI bus at 133MHz (but still in the limits of an Adaptec 29160 controller) >>> >>> The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean >>> 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're >>> lucky. 132M bytes/sec is the burst rate. There is substantial >> overhead on >>> the PCI bus that lowers that substantially. >>> >> Actually, he did not say "standard", and the current PCI standard _is_ 133 >> MHz. 33 MHz is ancient technology, 66 MHz is antique technology, >> 100 MHz is >> yesterday's news, and 133 MHz is the current defacto PCI standard. > > Er, no. The PCI bus is ONLY spec'd for 33Mhz, and 66Mhz, and 66MHz is > hardly ancient, as it's only in the past year that 66MHz slots have been > readily available on PCs. > > It is PCI-X that is spec'd for higher speeds, currently 66/100MHz, and no > one has any 133MHz operation as far as I know. The last time I looked, no > current system boards (from say Tyan, ASUS etc.) are available that support > PCI-X. Also, the last time I looked at the Adaptec web site, they did NOT > have a PCI-X RAID card (or even a controller chip) available...that's how > "ancient" the technology is! I stand corrected on the label of the bus, seeing as I was intending a generic answer to a generic statement. Check out the IWill XP-333-R motherboard sporting an SiS735 chipset: http://www6.tomshardware.com/mainboard/01q4/011008/index.html or http://www.littlewhitedog.com/reviews_hardware_00034.asp or http://www.iwill.com.tw/xp333/page_about.htm Front side bus speeds are 333 (not PCI) on the IWill, and the hard drive controller is ATA133, not SCSI. As such, I conceed the name of the standard PCI bus. > > The Adaptec 29160 is certainly NOT PCI-X anyway, it is ONLY 64 bit/32 bit > PCI compatible. That is what card was referenced above, and what was being > referred to. The PCI-X product lines from Adaptec will be Ultra 320 at this > point, and I'd say they are about a year away. > > And, yes, (I don't mean to sound obnoxious) I also know PCI very, very well > too. > Funny, it seems like I was sounding obnoxious in return. It must be contagious! ;-) Jim Snyder
RE: filmscanners: Best solution for HD and images
> You should know that not only do striped disks reduce reliability > and hence > increase risk but they also increase severity. As I've said, that's misinformation. Do you have any real MTBF testing data that backs up your claim, or is it just speculation? > i.e. any one drive of a multiple striped drive set failing WILL > lose ALL of > your data. This is just a silly statement. You lose ALL your data with a single disk just the same. > You should only use this arrangement where you keep very regular backups, > you use it largely as a scratch area or you can relatively easily recreate > the data. ONLY? That's absurd. Over %99.99 of computers are single hard disk computers...which stand the same or worse chance of data corruption from hard disk failure. One SHOULD back up, no doubt, and anyone who doesn't is being foolish, unless they can tolerate a failure. The fact is, disks don't fail regularly, even single disks. They DO fail though, hence the need for backup. > So why are you quoting statistical data when you don't understand basic > statistical analysis. Well, I do understand FAR more than basic statistical analysis, especially when it comes to MTBF, and am more than happy to compare qualifications with you on this topic off list, if you like. > The servo actuator will be used less but not anywhere near half > the time the > whole point of striping is that you use both drives at once. Er, thanks, having designed RAID controllers, I do know how RAID works. And yes, it IS near half. If you only have to move the actuator 1/2 the time/amount for each disk for a particular file, well, that's half to accomplish the same task. > > > The reality for MTBF of a RAID-0 will lie in between. > > > > But that means it doesn't change compared to a single drive... > > > But each drive is dependant on the other so the reliability of > the system is > compromised by either drive failing. Yes, but that doesn't mean the MTBF is lowered. > I suggest > you go get a > school book and have a look. That's the problem, I have intimate knowledge of the book, when it comes to MTBF. If you really had any first hand knowledge of MTBF testing, you would understand what I pointed out, not arguing against them. There is a LOT of misunderstanding WRT what MTBF really means, and how it should be tested. Do you have any REAL first hand experience with disk array MTBF? I do. > The problem with the web is that anybody who thinks they > understand jumps up > and tells the world. Soon everybody beleives it. That's true, but I don't base my knowledge on the web, I base it on my experience on having designed SCSI controllers and disk subsystems, as well as "being directly involved with" MTBF testing in the storage (and other) areas for one of the largest computer manufacturers. > I had a quick look for a reliable source and quickly noticed the weasel > words on the disk manufacturers site which generally say this about raid-0 > "great for speed but if you have a problem you lose ALL of your > data on all > of the disks". That's just a statement of fact, it's not weasel words. I am surprised you harp on that point, when it's just simple understanding. It's not a big deal. There's no conspiracy or lie...no one is trying to hide anything. > So they admit the severity No, they do NOT admit any "severity". It's just a simple statement of fact. > > So I'll leave it to an authority on RAID who don't have their interests in > > disk in manufacturing. Who can still make incorrect statements, which your reference is. I though find it interesting. Above you claim anyone can just look misinformation up on the web. Guess you're right. I think I've had enough of this, you aren't providing any data, just disagreement and speculation.
Re: filmscanners: Best solution for HD and images
on 11/12/01 10:34 PM, LAURIE SOLOMON at [EMAIL PROTECTED] wrote: >> Actually, both must be set up on the same IDE channel as masters. > > How does one do that? I thought that you could only have one master device > per channel; and it was the one that was connected to the end of the ribbon > cable and had its jumper set for master. > With two disks, you would be correct; but in this case, the two disks are going to act as one, so both must be set to be masters. Jim Snyder
Re: filmscanners: Best solution for HD and images
- Original Message - From: "Austin Franklin" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, November 13, 2001 2:52 PM Subject: RE: filmscanners: Best solution for HD and images FOR ALL THOSE A BIT BORED WITH THIS: You should know that not only do striped disks reduce reliability and hence increase risk but they also increase severity. i.e. any one drive of a multiple striped drive set failing WILL lose ALL of your data. You should only use this arrangement where you keep very regular backups, you use it largely as a scratch area or you can relatively easily recreate the data. If you don't believe me read on, but I will end this here and will not be replying to Austin's inevitable reply FOR AUSTIN (and any interested parties) >What I do > know, I know, and what I don't know, I know I don't know. So why are you quoting statistical data when you don't understand basic statistical analysis. > > > > MTBF of a RAID-0 system (or dual cpu/memory where one unit CAN > > NOT continue > > without the other) will always be lower than a single drive unless the > > standard deviation (they never quote SD) of the MTBF is zero. > > Well, if you take duty-cycle into account, which MTBF calculations do, you > will actually get higher MTBF for RAID 0, simply because the main failure is > the servo actuator, and when it is only being used for half the time...MTBF > will increase. > The servo actuator will be used less but not anywhere near half the time the whole point of striping is that you use both drives at once. Any marginal increase in MTBF rate of each single drive will not save you from the early device failure rate which as perm any one from N as any decent turf accountant will tell you shortens the odds. > > The reality for MTBF of a RAID-0 will lie in between. > > But that means it doesn't change compared to a single drive... > But each drive is dependant on the other so the reliability of the system is compromised by either drive failing. > > Cummalative failure rate is a much more useful figure for us and > > for a small > > number of fairly reliable inter-dependant devices this is nearly > > an additive > > figure - but not quite. > > That I completely disagree with. It is absolutely NOT additive. In fact, > as I pointed out above, you may get HIGHER reliability by using RAID 0 > simply because of duty cycle and the common failure mode, both of which are > a very important part of MTBF. > > > Seagate reckon about 3.41% (flat-line model) will fail during the first 5 > > years of use (assuming you only use it for 2400 hours a year [6 > > 1/2 hours a > > day]) : > > > > http://www.seagate.com/docs/pdf/newsinfo/disc/drive_reliability.pdf > > If you read that article you referenced, when they talk about multiple > disks, they are talking about multiple PLATTERS in a single disk, not > drives, so you can't derive the numbers you did for multiple drives from > that article. No where in that article did they discuss multiple drives. > > I suggest you go back to the link and look at pages 6 & 7 - the figures I used were for drives not platters. Whilst they don't discuss multiple drives simple statistical analysis will give you the answer. I suggest you go get a school book and have a look. > > And there is enough misinformation > > being thrown around here that it is just confusing everyone. > > You're right, even you are doing it! There is also a LOT of misinformation > available on the web. The basics are typically right, but the in-depth > understanding is usually lacking. The problem with the web is that anybody who thinks they understand jumps up and tells the world. Soon everybody beleives it. > > > ...such as the fact > > that RAID 0 is indeed less reliable than a single drive > > It's NOT a fact. It's speculation. Have you any test data to back that > claim up? I'd be willing to bet that is an incorrect claim, based on the > reason I stated in previous posts. > > I had a quick look for a reliable source and quickly noticed the weasel words on the disk manufacturers site which generally say this about raid-0 "great for speed but if you have a problem you lose ALL of your data on all of the disks". So they admit the severity but skip over the risk factor. I don't suppose we should be too surprised as they are after all trying to flog you the disks! So I'll leave it to an authority on RAID who don't have their interests in disk in manufacturing. http://www.adaptec.com/worldwide/product/markeditorial.html?cat=%2fTechnolog y%2fRAID&prodkey=raid_wp&type=Technology "The Mean Time Between Failure (MTBF) of the array is equal to the MTBF of an individual drive, divided by the number of drives in the array" - it's not quite true but as a rough simple approximation it is all but correct. Steve
RE: filmscanners: Best solution for HD and images
>= Original Message From Austin Franklin <[EMAIL PROTECTED]> = > >May be, kind of. Are you using a Compaq or DEC server? If so, and you have >an RSM II (Remote Server Manager) board in it, I designed that board (the >new PCI version)...and it can reset the computer...either by it self, or >from remote commands via a modem or Ethernet... If not, then I probably >didn't have anything remotely to do with it ;-) > >. There is no excuse for puns of this calibre. ;-) Regards, Steve
RE: Can we please move the RAID discussion off-list? (was RE: filmscanners: Best solution for HD and images)
> Can we PLEASE take this RAID discussion off-list? Sure, but you might want to heed your own advice, instead of throwing your $0.02 in here too! > And there is enough misinformation > being thrown around here that it is just confusing everyone. You're right, even you are doing it! There is also a LOT of misinformation available on the web. The basics are typically right, but the in-depth understanding is usually lacking. > ...such as the fact > that RAID 0 is indeed less reliable than a single drive It's NOT a fact. It's speculation. Have you any test data to back that claim up? I'd be willing to bet that is an incorrect claim, based on the reason I stated in previous posts.
Re: Can we please move the RAID discussion off-list? (was RE: filmscanners: Best solution for HD and images)
I, for one, am extremely interested in the RAID discussion and want it to stay on the list. It might be technically off-topic, but is useful knowledge for anyone comtemplating mass storage of images scanned from, uh, FILMSCANNERS. There are a lot of threads on this list that I'm not interested in. Rather than being a topic-nazi, I am not too lazy to use the DELETE key. Try it. Lloyd - Original Message - From: "Stuart Nixon" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, November 13, 2001 10:30 AM Subject: Can we please move the RAID discussion off-list? (was RE: filmscanners: Best solution for HD and images) > Can we PLEASE take this RAID discussion off-list? > > It is not directly related to scanners. And there is enough misinformation > being thrown around here that it is just confusing everyone. > > There is plenty of reference information for RAID systems on the web and > elsewhere; we don't need to clutter the list up with this IMHO. > > If people want reference information on RAID systems, such as the fact > that RAID 0 is indeed less reliable than a single drive or RAID 1 or 5, I > refer > you to information such as: > http://www.pcguide.com/ref/hdd/perf/raid/concepts/relRel-c.html > http://www.usbyte.com/common/raid_systems_3.htm#Extended%20Data%20Availabili > ty > http://204.56.132.222/courses/CIS312J/FAQ/raid-faq.txt > http://www.dansdata.com/raid.htm > http://www.csr.city.ac.uk/people/lorenzo.strigini/A701/A701material/lecture8 > /A701.8.FTnotes_010312A.pdf > http://www.sas.com/partners/directory/sun/wp/raid.txt > > Thanks > > Stuart > > p.s. I saw some Mac users were asking about IDE RAID systems. > Have a look at the new IDE/SCSI RAID 5 boxes from Promise and others, > which have IDE drives, and SCSI out. > http://www.promise.com/Products/UltraTrak/UltraTrak100%20TX4%20&%20TX8%20Dat > a%20Sheet.pdf > A 8 x 100GB IDE drive system gives about 700GB of usable space. I like > these > external RAID boxes, because they are low cost, have hot swappable drives > and power supplies, and plug straight into a Mac/PC/Unix SCSI controller. > > > [Original message] > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Austin Franklin > Sent: Tuesday, 13 November 2001 10:53 PM > To: [EMAIL PROTECTED] > Subject: RE: filmscanners: Best solution for HD and images > > > > MTBF of a RAID-0 system (or dual cpu/memory where one unit CAN > > NOT continue > > without the other) will always be lower than a single drive unless the > > standard deviation (they never quote SD) of the MTBF is zero. > > Well, if you take duty-cycle into account, which MTBF calculations do, you > will actually get higher MTBF for RAID 0, simply because the main failure is > the servo actuator, and when it is only being used for half the time...MTBF > will increase. > > > The reality for MTBF of a RAID-0 will lie in between. > > But that means it doesn't change compared to a single drive... > > > Cummalative failure rate is a much more useful figure for us and > > for a small > > number of fairly reliable inter-dependant devices this is nearly > > an additive > > figure - but not quite. > > That I completely disagree with. It is absolutely NOT additive. In fact, > as I pointed out above, you may get HIGHER reliability by using RAID 0 > simply because of duty cycle and the common failure mode, both of which are > a very important part of MTBF. > > > Seagate reckon about 3.41% (flat-line model) will fail during the first 5 > > years of use (assuming you only use it for 2400 hours a year [6 > > 1/2 hours a > > day]) : > > > > http://www.seagate.com/docs/pdf/newsinfo/disc/drive_reliability.pdf > > If you read that article you referenced, when they talk about multiple > disks, they are talking about multiple PLATTERS in a single disk, not > drives, so you can't derive the numbers you did for multiple drives from > that article. No where in that article did they discuss multiple drives. > > >
Can we please move the RAID discussion off-list? (was RE: filmscanners: Best solution for HD and images)
Can we PLEASE take this RAID discussion off-list? It is not directly related to scanners. And there is enough misinformation being thrown around here that it is just confusing everyone. There is plenty of reference information for RAID systems on the web and elsewhere; we don't need to clutter the list up with this IMHO. If people want reference information on RAID systems, such as the fact that RAID 0 is indeed less reliable than a single drive or RAID 1 or 5, I refer you to information such as: http://www.pcguide.com/ref/hdd/perf/raid/concepts/relRel-c.html http://www.usbyte.com/common/raid_systems_3.htm#Extended%20Data%20Availabili ty http://204.56.132.222/courses/CIS312J/FAQ/raid-faq.txt http://www.dansdata.com/raid.htm http://www.csr.city.ac.uk/people/lorenzo.strigini/A701/A701material/lecture8 /A701.8.FTnotes_010312A.pdf http://www.sas.com/partners/directory/sun/wp/raid.txt Thanks Stuart p.s. I saw some Mac users were asking about IDE RAID systems. Have a look at the new IDE/SCSI RAID 5 boxes from Promise and others, which have IDE drives, and SCSI out. http://www.promise.com/Products/UltraTrak/UltraTrak100%20TX4%20&%20TX8%20Dat a%20Sheet.pdf A 8 x 100GB IDE drive system gives about 700GB of usable space. I like these external RAID boxes, because they are low cost, have hot swappable drives and power supplies, and plug straight into a Mac/PC/Unix SCSI controller. [Original message] -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Austin Franklin Sent: Tuesday, 13 November 2001 10:53 PM To: [EMAIL PROTECTED] Subject: RE: filmscanners: Best solution for HD and images > MTBF of a RAID-0 system (or dual cpu/memory where one unit CAN > NOT continue > without the other) will always be lower than a single drive unless the > standard deviation (they never quote SD) of the MTBF is zero. Well, if you take duty-cycle into account, which MTBF calculations do, you will actually get higher MTBF for RAID 0, simply because the main failure is the servo actuator, and when it is only being used for half the time...MTBF will increase. > The reality for MTBF of a RAID-0 will lie in between. But that means it doesn't change compared to a single drive... > Cummalative failure rate is a much more useful figure for us and > for a small > number of fairly reliable inter-dependant devices this is nearly > an additive > figure - but not quite. That I completely disagree with. It is absolutely NOT additive. In fact, as I pointed out above, you may get HIGHER reliability by using RAID 0 simply because of duty cycle and the common failure mode, both of which are a very important part of MTBF. > Seagate reckon about 3.41% (flat-line model) will fail during the first 5 > years of use (assuming you only use it for 2400 hours a year [6 > 1/2 hours a > day]) : > > http://www.seagate.com/docs/pdf/newsinfo/disc/drive_reliability.pdf If you read that article you referenced, when they talk about multiple disks, they are talking about multiple PLATTERS in a single disk, not drives, so you can't derive the numbers you did for multiple drives from that article. No where in that article did they discuss multiple drives.
RE: filmscanners: Best solution for HD and images
> MTBF of a RAID-0 system (or dual cpu/memory where one unit CAN > NOT continue > without the other) will always be lower than a single drive unless the > standard deviation (they never quote SD) of the MTBF is zero. Well, if you take duty-cycle into account, which MTBF calculations do, you will actually get higher MTBF for RAID 0, simply because the main failure is the servo actuator, and when it is only being used for half the time...MTBF will increase. > The reality for MTBF of a RAID-0 will lie in between. But that means it doesn't change compared to a single drive... > Cummalative failure rate is a much more useful figure for us and > for a small > number of fairly reliable inter-dependant devices this is nearly > an additive > figure - but not quite. That I completely disagree with. It is absolutely NOT additive. In fact, as I pointed out above, you may get HIGHER reliability by using RAID 0 simply because of duty cycle and the common failure mode, both of which are a very important part of MTBF. > Seagate reckon about 3.41% (flat-line model) will fail during the first 5 > years of use (assuming you only use it for 2400 hours a year [6 > 1/2 hours a > day]) : > > http://www.seagate.com/docs/pdf/newsinfo/disc/drive_reliability.pdf If you read that article you referenced, when they talk about multiple disks, they are talking about multiple PLATTERS in a single disk, not drives, so you can't derive the numbers you did for multiple drives from that article. No where in that article did they discuss multiple drives.
RE: filmscanners: Best solution for HD and images
> >What I do > > know, I know, and what I don't know, I know I don't know. > > Mmmm, how do you know what you don't know :) Cause I don't know it ;-) > When I first wrote this about 5 mins ago I was about to send the > message when the PC reset itself. Did you cause that Austin ;) May be, kind of. Are you using a Compaq or DEC server? If so, and you have an RSM II (Remote Server Manager) board in it, I designed that board (the new PCI version)...and it can reset the computer...either by it self, or from remote commands via a modem or Ethernet... If not, then I probably didn't have anything remotely to do with it ;-)
Re: filmscanners: Best solution for HD and images
Austin wrote: >What I do > know, I know, and what I don't know, I know I don't know. Mmmm, how do you know what you don't know :) When I first wrote this about 5 mins ago I was about to send the message when the PC reset itself. Did you cause that Austin ;)
Re: filmscanners: Best solution for HD and images
MTBF of a RAID-0 system (or dual cpu/memory where one unit CAN NOT continue without the other) will always be lower than a single drive unless the standard deviation (they never quote SD) of the MTBF is zero. i.e they all fail simultaneously at MTBF and none before - pretty unlikely I think. Neither will the MTBF be halfed unless 1/2 the devices fail immediately and the other half last exactly 2x MTBF. The reality for MTBF of a RAID-0 will lie in between. MTBF is not really of great use for our puposes. Disk drive MTBF these days are quoted at about 250,000+ hours (>28 years continouous use)! I certainly have my doubts about these accelerated testing methods. But whatever happens to MTBF for multiple inter-dependant drives will be pretty irrelevant for the lifetime of our usage of the device. Cummalative failure rate is a much more useful figure for us and for a small number of fairly reliable inter-dependant devices this is nearly an additive figure - but not quite. Seagate reckon about 3.41% (flat-line model) will fail during the first 5 years of use (assuming you only use it for 2400 hours a year [6 1/2 hours a day]) : http://www.seagate.com/docs/pdf/newsinfo/disc/drive_reliability.pdf To calculate the failure rate for multiple inter-dependant devices you need to find the product of the survival rate and subtract it from 1. eg. Survival rate for 5 years is 100%-3.41% = 96.59% = 0.9659 So : 2 drives in raid-0 configuration running for 5 years 1-(0.9659*0.9659) = 0.06006975 = 6.0% - note this is not quite double. 3 drives in raid-0 configuration running for 5 years 1-(0.9659*0.965*0.9659) = 0.088737622625 = 8.9% - even further from triple Long before 5 years (AA excluded of course - has he got bored and gone to irritate other mailing lists?) you will probably want bigger and better storage . You can calculate figures for different expected usage yourself. Other manufacturers and probably other seagate product ranges will vary. Steve PS. Call me picky, but I notice that Seagate's actual warranty failure rate exceeds or equals their so-called "conservative" flat-line model. The author should seriously consider becoming a politician :-) - Original Message - From: "Austin Franklin" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, November 12, 2001 11:05 PM Subject: RE: filmscanners: Best solution for HD and images > > Seems like you have done everything and also know everything. > > Not everything, but having been an engineer for 25 years, I have done many > projects including digital imaging systems, and SCSI systems... What I do > know, I know, and what I don't know, I know I don't know. I don't just make > things up. > > > I don't > > know how your company (or you) determined MTBF of a RAID0 system but > > most companies as Compaq, IBM, Sun, Adaptec, etc. say that MTBF will > > decrease. > > There is only one article I have seen that says this, and I have had > discussions with the authors about this. Do you have any reference to > articles/spec sheets that make this claim? > > Interestingly enough, MTBF does not derate for adding a second CPU or for > adding more memory to the system... > > > Exactly because of the reduced MTBF of a system with multiple > > HDs Berkeley has suggested the RAID system. > > Is this "study" published anywhere? If so, I'd like to see it. > > > The RAID system is supposed > > to relax the impact of the reduced MTBF. That doesn't mean the MTBF > > becomes higher when a RAID system is deployed but it just makes it more > > likely that the failure can be repaired. > > Failure recovery is entirely different from MTBF. > > > I see though where your (company's) calculation might come from. > > The company was Digital, BTW. We had an entire department devoted to MTBF > testing...and specifically to storage MTBF assessment. > > > You > > can determine MTBF for a certain device by testing for example 1 > > drives for 1000 hours and then divide the total of 1*1000 hours by > > the number of failures. > > That's not really how you determine MTBF. MTBF is an average. You are > right, you need a large sample to test though. > > > Nevertheless, this calculation doesn't apply to RAID as a RAID system > > has to be considered as a single identity. > > Exactly, and that is why you don't get any decrease in MTBF by adding > drives. It's really simple. > > > So you cannot claim that > > because you have 10 HDs your RAID system is working 10*1=10 hours in > > each single hour. Your RAID system is ONE identity and therefore is > > working only 1 hours each hour it is up. Therefore the MTBF decreases. > >
RE: filmscanners: Best solution for HD and images
> on 11/11/01 10:21 PM, Austin Franklin at [EMAIL PROTECTED] wrote: > > >> the limit of a 32bit PCI bus at 133MHz (but still in the limits of an > >> Adaptec 29160 controller) > > > > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean > > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're > > lucky. 132M bytes/sec is the burst rate. There is substantial > overhead on > > the PCI bus that lowers that substantially. > > > Actually, he did not say "standard", and the current PCI standard _is_ 133 > MHz. 33 MHz is ancient technology, 66 MHz is antique technology, > 100 MHz is > yesterday's news, and 133 MHz is the current defacto PCI standard. Er, no. The PCI bus is ONLY spec'd for 33Mhz, and 66Mhz, and 66MHz is hardly ancient, as it's only in the past year that 66MHz slots have been readily available on PCs. It is PCI-X that is spec'd for higher speeds, currently 66/100MHz, and no one has any 133MHz operation as far as I know. The last time I looked, no current system boards (from say Tyan, ASUS etc.) are available that support PCI-X. Also, the last time I looked at the Adaptec web site, they did NOT have a PCI-X RAID card (or even a controller chip) available...that's how "ancient" the technology is! The Adaptec 29160 is certainly NOT PCI-X anyway, it is ONLY 64 bit/32 bit PCI compatible. That is what card was referenced above, and what was being referred to. The PCI-X product lines from Adaptec will be Ultra 320 at this point, and I'd say they are about a year away. And, yes, (I don't mean to sound obnoxious) I also know PCI very, very well too.
Re: filmscanners: Best solution for HD and images
on 11/11/01 10:21 PM, Austin Franklin at [EMAIL PROTECTED] wrote: >> the limit of a 32bit PCI bus at 133MHz (but still in the limits of an >> Adaptec 29160 controller) > > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're > lucky. 132M bytes/sec is the burst rate. There is substantial overhead on > the PCI bus that lowers that substantially. > Actually, he did not say "standard", and the current PCI standard _is_ 133 MHz. 33 MHz is ancient technology, 66 MHz is antique technology, 100 MHz is yesterday's news, and 133 MHz is the current defacto PCI standard.
RE: filmscanners: Best solution for HD and images
>Actually, both must be set up on the same IDE channel as masters. How does one do that? I thought that you could only have one master device per channel; and it was the one that was connected to the end of the ribbon cable and had its jumper set for master. At any rate, I am off to check out the web site you mentioned and do some further research. Thanks for the reference. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Jim Snyder Sent: Monday, November 12, 2001 8:10 PM To: [EMAIL PROTECTED] Subject: Re: filmscanners: Best solution for HD and images on 11/12/01 12:22 AM, LAURIE SOLOMON at [EMAIL PROTECTED] wrote: > To Preben: > > Thanks for your response and patience. The Abit board does permit JBOD; but > it does not provide RAID 5 as you have noted. When I asked about what > appeared to be a contradiction between what you suggested and what the ABIT > manual said I did not realize that there was a RAID 5 and that this was what > you were referring to. I apologize for my ignorance; but I am not sorry I > asked. Out of my asking, I learned about RAID 5, which I would not have > known about if I did not raise my question about the apparent contradiction. > > To all who have posted on the subject of RAID: > > Thank you; it has been an education. I have a few additional questions that > I need to be educated on and would appreciate any information that you could > provide me. > > (1) If one sets up a RAID 0 (striping)with two 60GB disks, must each hard > drive be the master on a separate IDE channel or can they be set up as > master-slave on the same IDE channel? Actually, both must be set up on the same IDE channel as masters. There is a procedure to follow before doing so, but this is the end result. > > (2) If one sets up a RAID 0 (striping)with two 60GB disks under WIN 98, can > one establish partitions for the array or must it be a single partition? In > formatting the drives to be used in a RAID array, how does one format each > of the disks with Fdisk (each disk being a brand new disk) with respect to > partitions? Each is first done separately, but then there are steps to follow before arriving at the end result. Check the website of www.storagereview.com for details. They have a great article on setting up RAID arrays. > > (3)If one sets up a RAID 0 (striping)with two 60GB disks under WIN 98, can > one use utilities such as ScanDisk and Disk Defragmenter on the RAID array, > on individual hard drive disks in the array, or - if logical partitions are > usable with the array or disks in the array - on the partitions? Yes. Both disc are effectively one disk when properly set up. Remember, data is being striped to both as if they are one disc. Jim Snyder
Re: filmscanners: Best solution for HD and images
on 11/12/01 4:07 AM, Mike Bloor at [EMAIL PROTECTED] wrote: > Preben, > > At 12:34 11/11/01 +0100, you wrote: > >> Lastly, these stand alone Raid cards - unlike raid solutions on >> motherbords - have their own processors on board which takes over all the >> hard work, freeing up your system processor. > > I knew that RAID in software (e.g. as part of Windows NT4) worked on the > main CPU, but I thought that PC's with additional RAID hardware on the > motherboard (such as many of the Dell servers) off loaded these tasks. > They reduce the load, but do not completely offload it. The CPU is still the master controller. Jim Snyder
Re: filmscanners: Best solution for HD and images
on 11/12/01 12:22 AM, LAURIE SOLOMON at [EMAIL PROTECTED] wrote: > To Preben: > > Thanks for your response and patience. The Abit board does permit JBOD; but > it does not provide RAID 5 as you have noted. When I asked about what > appeared to be a contradiction between what you suggested and what the ABIT > manual said I did not realize that there was a RAID 5 and that this was what > you were referring to. I apologize for my ignorance; but I am not sorry I > asked. Out of my asking, I learned about RAID 5, which I would not have > known about if I did not raise my question about the apparent contradiction. > > To all who have posted on the subject of RAID: > > Thank you; it has been an education. I have a few additional questions that > I need to be educated on and would appreciate any information that you could > provide me. > > (1) If one sets up a RAID 0 (striping)with two 60GB disks, must each hard > drive be the master on a separate IDE channel or can they be set up as > master-slave on the same IDE channel? Actually, both must be set up on the same IDE channel as masters. There is a procedure to follow before doing so, but this is the end result. > > (2) If one sets up a RAID 0 (striping)with two 60GB disks under WIN 98, can > one establish partitions for the array or must it be a single partition? In > formatting the drives to be used in a RAID array, how does one format each > of the disks with Fdisk (each disk being a brand new disk) with respect to > partitions? Each is first done separately, but then there are steps to follow before arriving at the end result. Check the website of www.storagereview.com for details. They have a great article on setting up RAID arrays. > > (3)If one sets up a RAID 0 (striping)with two 60GB disks under WIN 98, can > one use utilities such as ScanDisk and Disk Defragmenter on the RAID array, > on individual hard drive disks in the array, or - if logical partitions are > usable with the array or disks in the array - on the partitions? Yes. Both disc are effectively one disk when properly set up. Remember, data is being striped to both as if they are one disc. Jim Snyder
RE: filmscanners: Best solution for HD and images
> ... The biggest increase in performance is from one to > two drives, Absolutely, and that's per channel, so a two channel system would greatly benefit from four drives, two on each channel. Moreno, thanks for your post, it was right on the money.
RE: filmscanners: Best solution for HD and images
> Seems like you have done everything and also know everything. Not everything, but having been an engineer for 25 years, I have done many projects including digital imaging systems, and SCSI systems... What I do know, I know, and what I don't know, I know I don't know. I don't just make things up. > I don't > know how your company (or you) determined MTBF of a RAID0 system but > most companies as Compaq, IBM, Sun, Adaptec, etc. say that MTBF will > decrease. There is only one article I have seen that says this, and I have had discussions with the authors about this. Do you have any reference to articles/spec sheets that make this claim? Interestingly enough, MTBF does not derate for adding a second CPU or for adding more memory to the system... > Exactly because of the reduced MTBF of a system with multiple > HDs Berkeley has suggested the RAID system. Is this "study" published anywhere? If so, I'd like to see it. > The RAID system is supposed > to relax the impact of the reduced MTBF. That doesn't mean the MTBF > becomes higher when a RAID system is deployed but it just makes it more > likely that the failure can be repaired. Failure recovery is entirely different from MTBF. > I see though where your (company's) calculation might come from. The company was Digital, BTW. We had an entire department devoted to MTBF testing...and specifically to storage MTBF assessment. > You > can determine MTBF for a certain device by testing for example 1 > drives for 1000 hours and then divide the total of 1*1000 hours by > the number of failures. That's not really how you determine MTBF. MTBF is an average. You are right, you need a large sample to test though. > Nevertheless, this calculation doesn't apply to RAID as a RAID system > has to be considered as a single identity. Exactly, and that is why you don't get any decrease in MTBF by adding drives. It's really simple. > So you cannot claim that > because you have 10 HDs your RAID system is working 10*1=10 hours in > each single hour. Your RAID system is ONE identity and therefore is > working only 1 hours each hour it is up. Therefore the MTBF decreases. Why does the MTBF decrease? You have a magical "therefore" that doesn't follow. If you tested 1000 drives by themselves, and you got an MTBF of 1,000,000 hours, let's say...take those 1000 drives, and make 500 RAID 0 systems, and your MTBF will NOT decrease notably, if at all, from drive failure. It may from other factors like power supply or thermal, but not from drive failure.
Re: filmscanners: Best solution for HD and images
> > Seems like you have done everything and also know everything. ROTFLMAO -- Lawrence W. Smith Photography http://www.lwsphoto.com [EMAIL PROTECTED] --
RE: filmscanners: Best solution for HD and images
> > No one uses narrow SCSI for RAID, and it doesn't have to be SSA. SCSI uses > > four bits for SCSI ID, which makes SIXTEEN devices. > The U-160 card I know (Adaptec 29160) allows the connection of 7 devices > each controller while permitting 16 addresses. A device IS the same as a SCSI address in this case. Narrow SCSI can have 8 devices (three bits), one being the controller. Wide SCSI, which is what any RAID system is going to use (or why bother) has four bits, or 16 devices/addresses. > Single SCSI card can connect up to 7 or 15 devices per channel If you are using narrow devices, 7 is the number, wide devices, 15 is the number. As I said, it's not worth doing RAID on a narrow drive, since there really aren't any SCSI 160 drives that are narrow that I know of... > > A correct implementation of RAID 5 will write all at the same time. RAID 5 > > is NOT slowed down because it has to do multiple writes, it's because, > > sometimes, depending on stripe size, it has to read, calculate parity, then > > write. RAID 5 is slowed down for reads, since the parity is distributed > > across drives. > RAID Level 5 > ...the performance for reads tends to be considerably lower... As I said, but note that there was no penalty for writes. Writes are cached anyway. > > > the benchmarks AREN'T running out of disk cache...that hardly tests the > > disk > > > speed. You'll be lucky to get even near 80, if even 60. > I am meaning ... each disk runs at 35 or 30MB/s + SCSI architecture allows parallel operations True. > then I can add them to have an aggregated transfer rate . It might be I will never achieve 100% > real addition , but I believe the aggregated transfer rate is close to the summary > of the single aggregated transfer rates of each disk. They DO increase, but not by direct addition, as you implied. > Ultra160 uses double transition clocking to send 2 bits of data per clock cycle instead of one, Two BYTES of data per clock. > > > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean > > > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're > > > lucky. 132M bytes/sec is the burst rate. There is substantial overhead > > on > > > the PCI bus that lowers that substantially. > > > > > > > YEP ! I can achieve the saturation of bus before achieving the > > saturation of > > the controller (Adaptec 29160 is a 64 bit adapter). > Correct ... then I can achieve the saturation (80% of 132MB/s) of the bus before > saturating the max controller throughput right ? Yes. > > 64 bit PCI is 264M bytes/sec for 33MHz PCI, > > and 528M bytes/sec for 66MHz PCI...so there is NO way you are saturating the > > PCI bus especially with a 64 bit controller. You previously said you were > > on a 32 bit PCI bus. > No, no ! As far as I know the Intel PC has a 32bit PCI but Adaptec has implemented > a 64bit adpater over a 32bit bus ... Absolutely not. 32 bit PCI IS only 32 bits wide. Only 64 bit PCI is 64 bits wide. > they are doubling the cycle and thus keeping the compatibility with old-standard > PCI-Intel systems while improving the speed and throughput of the adapter > (compared with 32bit adapters). A 32 bit 33MHz PCI bus only gives 132M byte/sec burst transfer speed. If you have a 64 bit device on a 32 bit PCI bus, it is acting as a 32 bit device. The upper 32 bits are not used. There is no such thing as "cycle doubling" on PCI.
Re: filmscanners: Best solution for HD and images
>> No one uses narrow SCSI for RAID, and it doesn't have to be SSA. SCSI uses >> four bits for SCSI ID, which makes SIXTEEN devices. >The U-160 card I know (Adaptec 29160) allows the connection of 7 devices each controller while permitting 16 addresses. The 7 device limit applies if you connect narrow SCSI devices. If you are using Ultra Wide devices or drives, then you can use up to the full 15 device limit. The 29160 has only one controller (that's why it's called "single channel"). > I am meaning ... each disk runs at 35 or 30MB/s + SCSI architecture allows parallel operations then I can add them to have an > aggregated transfer rate . It might be I will never achieve 100% real addition , but I believe the aggregated transfer rate is> close to the summary of the single aggregated transfer rates of each disk. If you add a second, striped drive (Raid 0), you can usually expect disk throughput to double. If you add a third drive, the performance will be less than triple. The biggest increase in performance is from one to two drives, then the additive performance benefits of each additional drive is proportionately less. A six drive Raid 0 setup, for instance, will be fast, but nowhere near the sum of the transfer rates of each individual disk. > > 64 bit PCI is 264M bytes/sec for 33MHz PCI, > > and 528M bytes/sec for 66MHz PCI...so there is NO way you are saturating the > > PCI bus especially with a 64 bit controller. You previously said you were > > on a 32 bit PCI bus. > No, no ! As far as I know the Intel PC has a 32bit PCI but Adaptec has implemented a 64bit adpater over a 32bit bus > ... they are doubling the cycle and thus keeping the compatibility with old-standard PCI-Intel systems while improving > the speed and throughput of the adapter (compared with 32bit adapters). Intel-based PC's can have either 32 bit or 64 bit PCI busses, it just depends on the motherboard. Many server and workstation motherboards have one or more 64 bit PCI slots; most desktops have 32 bit PCI slots only. The Adaptec 29160 can run at either 32 or 64 bits. If you install the 29160 into a 32 bit PCI slot, it will still run fine, but it will be running at the slower 32 bits, not 64 bits.
RE: filmscanners: Best solution for HD and images
> It *IS* more unsafe to use RAID0. And MTBF *IS* additive. > > No and no. I designed SCSI controllers and disk subsystems (for the > storage > division of one of the top computer manufacturers) for years, as well > as > tested disk subsystems. I know how MTBF is determined. Seems like you have done everything and also know everything. I don't know how your company (or you) determined MTBF of a RAID0 system but most companies as Compaq, IBM, Sun, Adaptec, etc. say that MTBF will decrease. Exactly because of the reduced MTBF of a system with multiple HDs Berkeley has suggested the RAID system. The RAID system is supposed to relax the impact of the reduced MTBF. That doesn't mean the MTBF becomes higher when a RAID system is deployed but it just makes it more likely that the failure can be repaired. That is not the case for RAID-0 though which is why many people said that RAID0 does not really belong to RAID which asks for redundant drives (which are obviously non-existent in RAID0). I see though where your (company's) calculation might come from. You can determine MTBF for a certain device by testing for example 1 drives for 1000 hours and then divide the total of 1*1000 hours by the number of failures. That way you don't have to test one drive for a long time (it's lifetime and then replace it with a new one). Nevertheless, this calculation doesn't apply to RAID as a RAID system has to be considered as a single identity. So you cannot claim that because you have 10 HDs your RAID system is working 10*1=10 hours in each single hour. Your RAID system is ONE identity and therefore is working only 1 hours each hour it is up. Therefore the MTBF decreases. Nevertheless, the reliability of HDs are quite high these days and therefore I wouldn't hesitate to have a RAID0 system with a couple of HDs for my imaging purposes and adequate backup. As a matter of fact, I am considering updating my computer system and in that case I am going to setup a RAID0 system with two fast 80GB. End of discussion on my side. Robert __ Do You Yahoo!? Find a job, post your resume. http://careers.yahoo.com
Re: filmscanners: Best solution for HD and images
ation of bus before achieving the> > saturation of> > the controller (Adaptec 29160 is a 64 bit adapter).  Correct ... then I can achieve the saturation (80% of 132MB/s) of the bus before saturating the max controller throughput right ?  64 bit PCI is 264M bytes/sec for 33MHz PCI,> and 528M bytes/sec for 66MHz PCI...so there is NO way you are saturating the> PCI bus especially with a 64 bit controller. You previously said you were> on a 32 bit PCI bus. No, no ! As far as I know the Intel PC has a 32bit PCI but Adaptec has implemented a 64bit adpater over a 32bit bus ... they are doubling the cycle and thus keeping the compatibility with old-standard PCI-Intel systems while improving the speed and throughput of the adapter (compared with 32bit adapters).  Sincerely.  Ezio  www.lucenti.com e-photography site   - Original Message - From: "Austin Franklin" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, November 12, 2001 4:50 PM Subject: RE: filmscanners: Best solution for HD and images > > > > Thus in the case of SCSI where you cannot (by definition) overcome the> > > > number of 6 devices x chain/controller,> > >> > > WHAT SCSI are you talking about? Try 16. not 6.> > >> >> > How many addresses have you per controller ?> > from 0 to 6 = 7 but 1 is the controller itself.> > SCSI is not IBM SSA . SCSI = 6 devices x controller/chain ; SSA> > 16 devices x> > controller/loop> > No one uses narrow SCSI for RAID, and it doesn't have to be SSA. SCSI uses> four bits for SCSI ID, which makes SIXTEEN devices.> > > > That's not true. There is no "double write", both the data/parity is> > > written at the same time. Parity can easily be calculated on the fly.> > >> >> > YEP ! and who does write it on the disk in a different area/zone/disk ?> > A correct implementation of RAID 5 will write all at the same time. RAID 5> is NOT slowed down because it has to do multiple writes, it's because,> sometimes, depending on stripe size, it has to read, calculate parity, then> write. RAID 5 is slowed down for reads, since the parity is distributed> across drives.> > > > Run some benchmarks on your system and see for your self.> > Also, make sure> > > the benchmarks AREN'T running out of disk cache...that hardly tests the> > disk> > > speed. You'll be lucky to get even near 80, if even 60.> >> > My data are the output of a benchmark and not the theoretical max speed.> > What benchmark are you using? I do not believe you are getting 134M> bytes/sec, it is physically impossible.> > > Yes you can add because SCSI can parallelize the requests while> > IDE cannot.> > IDE CAN parallelize, and as I said, you can't just add transfer rates, it> doesn't work that way.> > > > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean> > > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're> > > lucky. 132M bytes/sec is the burst rate. There is substantial overhead> > on> > > the PCI bus that lowers that substantially.> > >> >> > YEP ! I can achieve the saturation of bus before achieving the> > saturation of> > the controller (Adaptec 29160 is a 64 bit adapter).> > Now you're talking silly. You said you had four disks. The MAX media> transfer rate from those disks is around 35M bytes/sec. Even if they were> able (which they are NOT) to sustain that over the SCSI/PCI bus at full> speed, that's 140M bytes/sec. 64 bit PCI is 264M bytes/sec for 33MHz PCI,> and 528M bytes/sec for 66MHz PCI...so there is NO way you are saturating the> PCI bus especially with a 64 bit controller. You previously said you were> on a 32 bit PCI bus.> >
Re: filmscanners: Best solution for HD and images
I'll take this off list . Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "Austin Franklin" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, November 12, 2001 4:50 PM Subject: RE: filmscanners: Best solution for HD and images > > > > Thus in the case of SCSI where you cannot (by definition) overcome the > > > > number of 6 devices x chain/controller, > > > > > > WHAT SCSI are you talking about? Try 16. not 6. > > > > > > > How many addresses have you per controller ? > > from 0 to 6 = 7 but 1 is the controller itself. > > SCSI is not IBM SSA . SCSI = 6 devices x controller/chain ; SSA > > 16 devices x > > controller/loop > > No one uses narrow SCSI for RAID, and it doesn't have to be SSA. SCSI uses > four bits for SCSI ID, which makes SIXTEEN devices. > > > > That's not true. There is no "double write", both the data/parity is > > > written at the same time. Parity can easily be calculated on the fly. > > > > > > > YEP ! and who does write it on the disk in a different area/zone/disk ? > > A correct implementation of RAID 5 will write all at the same time. RAID 5 > is NOT slowed down because it has to do multiple writes, it's because, > sometimes, depending on stripe size, it has to read, calculate parity, then > write. RAID 5 is slowed down for reads, since the parity is distributed > across drives. > > > > Run some benchmarks on your system and see for your self. > > Also, make sure > > > the benchmarks AREN'T running out of disk cache...that hardly tests the > > disk > > > speed. You'll be lucky to get even near 80, if even 60. > > > > My data are the output of a benchmark and not the theoretical max speed. > > What benchmark are you using? I do not believe you are getting 134M > bytes/sec, it is physically impossible. > > > Yes you can add because SCSI can parallelize the requests while > > IDE cannot. > > IDE CAN parallelize, and as I said, you can't just add transfer rates, it > doesn't work that way. > > > > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean > > > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're > > > lucky. 132M bytes/sec is the burst rate. There is substantial overhead > > on > > > the PCI bus that lowers that substantially. > > > > > > > YEP ! I can achieve the saturation of bus before achieving the > > saturation of > > the controller (Adaptec 29160 is a 64 bit adapter). > > Now you're talking silly. You said you had four disks. The MAX media > transfer rate from those disks is around 35M bytes/sec. Even if they were > able (which they are NOT) to sustain that over the SCSI/PCI bus at full > speed, that's 140M bytes/sec. 64 bit PCI is 264M bytes/sec for 33MHz PCI, > and 528M bytes/sec for 66MHz PCI...so there is NO way you are saturating the > PCI bus especially with a 64 bit controller. You previously said you were > on a 32 bit PCI bus. > >
Re: filmscanners: Best solution for HD and images
Many motherboard RAID controllers don't have extra processing capacity, they just have the hardware controller and firmware for BIOS support. [EMAIL PROTECTED] (Mike Bloor) wrote: > Preben, > > At 12:34 11/11/01 +0100, you wrote: > > >Lastly, these stand alone Raid cards - unlike raid solutions on > >motherbords - have their own processors on board which takes over > all the > >hard work, freeing up your system processor. > > I knew that RAID in software (e.g. as part of Windows NT4) worked on > the main CPU, but I thought that PC's with additional RAID hardware on > the motherboard (such as many of the Dell servers) off loaded these > tasks.
Re: filmscanners: Best solution for HD and images
But they don't! I have a RAID0+1 array of four 30G IBM 7200 drives. At today's prices, those drives would cost £90 each inc VAT, making £360. A single 73G 7200 SCSII drive costs £650! SCSII drives are restricted to 18, 36 and 73G so I couldn't find a 60GB one to compare. So a whole RAID array with the speed and safety advantages costs just more than half as much as a single SCSII drive of similar capacity. All these prices were taken from www.insight.com/uk [EMAIL PROTECTED] (Ezio c/o TIN) wrote: > I really cannot understand why it would be needed such a complication > and > dependancy from the controller vendor when the SCSI hard drives cost > almost > the same (or 20% more max) of IDE hard drives !
RE: filmscanners: Best solution for HD and images
> > > Thus in the case of SCSI where you cannot (by definition) overcome the > > > number of 6 devices x chain/controller, > > > > WHAT SCSI are you talking about? Try 16. not 6. > > > > How many addresses have you per controller ? > from 0 to 6 = 7 but 1 is the controller itself. > SCSI is not IBM SSA . SCSI = 6 devices x controller/chain ; SSA > 16 devices x > controller/loop No one uses narrow SCSI for RAID, and it doesn't have to be SSA. SCSI uses four bits for SCSI ID, which makes SIXTEEN devices. > > That's not true. There is no "double write", both the data/parity is > > written at the same time. Parity can easily be calculated on the fly. > > > > YEP ! and who does write it on the disk in a different area/zone/disk ? A correct implementation of RAID 5 will write all at the same time. RAID 5 is NOT slowed down because it has to do multiple writes, it's because, sometimes, depending on stripe size, it has to read, calculate parity, then write. RAID 5 is slowed down for reads, since the parity is distributed across drives. > > Run some benchmarks on your system and see for your self. > Also, make sure > > the benchmarks AREN'T running out of disk cache...that hardly tests the > disk > > speed. You'll be lucky to get even near 80, if even 60. > > My data are the output of a benchmark and not the theoretical max speed. What benchmark are you using? I do not believe you are getting 134M bytes/sec, it is physically impossible. > Yes you can add because SCSI can parallelize the requests while > IDE cannot. IDE CAN parallelize, and as I said, you can't just add transfer rates, it doesn't work that way. > > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean > > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're > > lucky. 132M bytes/sec is the burst rate. There is substantial overhead > on > > the PCI bus that lowers that substantially. > > > > YEP ! I can achieve the saturation of bus before achieving the > saturation of > the controller (Adaptec 29160 is a 64 bit adapter). Now you're talking silly. You said you had four disks. The MAX media transfer rate from those disks is around 35M bytes/sec. Even if they were able (which they are NOT) to sustain that over the SCSI/PCI bus at full speed, that's 140M bytes/sec. 64 bit PCI is 264M bytes/sec for 33MHz PCI, and 528M bytes/sec for 66MHz PCI...so there is NO way you are saturating the PCI bus especially with a 64 bit controller. You previously said you were on a 32 bit PCI bus.
Re: filmscanners: Best solution for HD and images
It of course depends on the motherboard. Several manufacturers in the retail market (e.g. Tyan, Supermicro) do make motherboards with SCSI raid options in which the raid controller handles the processing. The IDE based raid options, to the best of my knowledge, do not handle the processing. I should add that for the purposes described here specifically (fast read/writes for photo editing) this should not be an issue; even if the host cpu gets 'bogged down' while writing, it is at a time when you most likely aren't depending on it for something else. It becomes more important as you demand more simultaneous work from the computer. In my experience, I rarely do anything else on my PC when I am editing pictures (ok, maybe playing a CD). In my opinion, SCSI's performance advantages on anything up to a true workstation class computer are long since gone. Advances in the IDE standard and it's drives make it far more attractive. SCSI doesn't become a good option until one is performing multiple simultaneous read/writes. A single SCSI drive in a PC doesn't make much sense to me. IDE are larger and transfer data at the same speed. Pat --- Mike Bloor <[EMAIL PROTECTED]> wrote: > Preben, > > At 12:34 11/11/01 +0100, you wrote: > > >Lastly, these stand alone Raid cards - unlike raid > solutions on > >motherbords - have their own processors on board > which takes over all the > >hard work, freeing up your system processor. > > I knew that RAID in software (e.g. as part of > Windows NT4) worked on the > main CPU, but I thought that PC's with additional > RAID hardware on the > motherboard (such as many of the Dell servers) off > loaded these tasks. > > > > > > > > Mike Bloor __ Do You Yahoo!? Find a job, post your resume. http://careers.yahoo.com
Re: Re: filmscanners: RE: filmscanners: Best solution for HD and images
Just thought I would add that on single user systems dedicating memory slightly greater than scan size to file cache will give as near instant write response as your software and processor is capable of achieving (even non-raid). In fact during write opertions raid 0 on a memory handicapped machine will be slower than a single drive machine with loads of memory. Read operations will be quicker with raid 0 unless the data you're loading is still in file cache. Adding memory is much cheaper than raid drive systems as 256MB of top quality SDRAM/DDR ram available for less than £30. If you have a smart raid 1 solution (stripes when reading) and lots of available memory for disk cache then performance for a single user doing scanning/PS will be indistinguishable from raid 0. But you do lose disk space in exchange for reliability. Steve ___ Never pay another Internet phone bill! Freeserve AnyTime, for all the Internet access you want, day and night, only £12.99 per month. Sign-up at http://www.freeserve.com/time/anytime
Re: filmscanners: Best solution for HD and images
Preben, At 12:34 11/11/01 +0100, you wrote: >Lastly, these stand alone Raid cards - unlike raid solutions on >motherbords - have their own processors on board which takes over all the >hard work, freeing up your system processor. I knew that RAID in software (e.g. as part of Windows NT4) worked on the main CPU, but I thought that PC's with additional RAID hardware on the motherboard (such as many of the Dell servers) off loaded these tasks. Mike Bloor
filmscanners: Re: filmscanners: Re: filmscanners: Best solution for HD and images
Ezio wrote: >Congratulations for the professional results Rob ! :-) Thanks! Now if I can get articles printed in mags where I get *paid* for it... > I have 3 U160 IBM 1rpm and NO FANS at all > while the box is a cheap box I have assembled > on my own with a 350W power supply ( 20$ the > power supply at any shop) and a cage costing > 30$ at any shop. Do you have airconditioning in the room where the computer is located, and do the summertime conditions reach 36C and 90+% humidity? Or let's be more realistic - night time temps of 28C and 90% humidity? I don't get to use my home computer during the day much other than weekends! Seriously though - could you please email me (off list) the address of the company you are buying the drives from? It would be nice to have a fast SCSI drive to stream data to and from. My motherboard has a U2W interface (LVD). I'd be impressed if the shipping costs to Oz were similar. Thanks, Rob Rob Geraghty [EMAIL PROTECTED] http://wordweb.com
RE: filmscanners: Best solution for HD and images
> It *IS* more unsafe to use RAID0. And MTBF *IS* additive. No and no. I designed SCSI controllers and disk subsystems (for the storage division of one of the top computer manufacturers) for years, as well as tested disk subsystems. I know how MTBF is determined. > Actually, > more exactly it is reduced and not increased. If you have 1 drive with > a MTBF of 10 hours you can expect an error every 10 hours in > average. That's NOT MTBF. MTBF is FAILURE (that's what the "F" in MTBF is for), not error. It's just like tires on a car, they all wear out at just about the same time. When you roll dice, you have the same chance to roll double 6's each time, even if you just rolled 5 of them in a row. MTBF is a very complex statistical determination, but suffice to say, it is absolutely NOT additive at all, and I assure you that adding a second disk to your system to perform RAID 0 does NOT decrease the reliability of your system measurably (unless some other factor is involved, like cooling or power supply). You stand just as much of a chance of choosing the "failure" drive for your single drive then you do having it as part of your RAID 0 system.
Re: filmscanners: Re: filmscanners: Best solution for HD and images
Congratulations for the professional results Rob ! :-) Rob , we have been here before , you are right , but I am not living in USA , but in Italy and I buy on eBay USA with credit card, I have 3 U160 IBM 1rpm and NO FANS at all while the box is a cheap box I have assembled on my own with a 350W power supply ( 20$ the power supply at any shop) and a cage costing 30$ at any shop. IDE and SCSI when coming to the HDA (hard disk files) are the same but different protocol implementation just IDE a little bit more obsolete in facts they follow the SCSI implementations by 6 or 12 months after. Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "Rob Geraghty" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, November 12, 2001 3:06 AM Subject: filmscanners: Re: filmscanners: Best solution for HD and images > Ezio wrote: > >I really cannot understand why it would be needed such a complication and > >dependancy from the controller vendor when the SCSI hard drives cost almost > >the same (or 20% more max) of IDE hard drives ! > > Ezio, I know we've been here before, but SCSI isn't a cheap option for everyone. > Certainly, if I was in the US and had access to the sorts of prices you > quote from ebay, I'd use SCSI... well, there's other problems. If I wanted > to use a 10Krpm SCSI drive I'd also have to fit a cooling fan in my computer > and move house to somewhere that had air-conditioning. I simply couldn't > run such hard drives in 30+C temperatures reliably. I can buy two 7200rpm > IDE drives locally for about US$250, plus another US$45 for an IDE RAID > controller. The SCSI option (in Australia) would cost me US$200 for the > SCSI controller card, and at least US$500 for an equivalent capacity 10Krpm > SCSI drive. Plus, the IDE drives would behave themselves more reliably outside > of an airconditioned office. > > Obscanning: on a completely different topic, I've just taken a roll of Provia > 100F using two L series Canon lenses. I should get back the results tomorrow > so I can get an idea of how much difference the lenses made in scanning > on the LS30. > > Rob > > PS I got two more of my photos on the magazine cover. Scanned with the LS30 > and they look great! :) > > > Rob Geraghty [EMAIL PROTECTED] > http://wordweb.com > > >
Re: filmscanners: Best solution for HD and images
> > Thus in the case of SCSI where you cannot (by definition) overcome the > > number of 6 devices x chain/controller, > > WHAT SCSI are you talking about? Try 16. not 6. > How many addresses have you per controller ? from 0 to 6 = 7 but 1 is the controller itself. SCSI is not IBM SSA . SCSI = 6 devices x controller/chain ; SSA 16 devices x controller/loop > That's not true. There is no "double write", both the data/parity is > written at the same time. Parity can easily be calculated on the fly. > YEP ! and who does write it on the disk in a different area/zone/disk ? > Run some benchmarks on your system and see for your self. Also, make sure > the benchmarks AREN'T running out of disk cache...that hardly tests the disk > speed. You'll be lucky to get even near 80, if even 60. My data are the output of a benchmark and not the theoretical max speed. Yes you can add because SCSI can parallelize the requests while IDE cannot. > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're > lucky. 132M bytes/sec is the burst rate. There is substantial overhead on > the PCI bus that lowers that substantially. > YEP ! I can achieve the saturation of bus before achieving the saturation of the controller (Adaptec 29160 is a 64 bit adapter). Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "Austin Franklin" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Monday, November 12, 2001 4:21 AM Subject: RE: filmscanners: Best solution for HD and images > > Thus in the case of SCSI where you cannot (by definition) overcome the > > number of 6 devices x chain/controller, > > WHAT SCSI are you talking about? Try 16. not 6. > > > BTW , this method compulsorily implies a DOUBLE WRITING need i.e. > > write the > > data + write the new parity (even if on another disk) and this is > > meaning a > > LOSS OF SPEED/EFFICIENCY (relatively to the achievable speed/efficiency of > > the disks) > > That's not true. There is no "double write", both the data/parity is > written at the same time. Parity can easily be calculated on the fly. > > > Yesterday night I have bought on eBay an IBM U-160 1rpm 18GB new and > > under warranty for 102 USD + 20$ of shipment to Italy from USA > > and this unit > > will be the fourth inside my system while having 2 x CD/R (IDE) > > and 1 x DVD > > (IDE) . > > My aggregated sustained transfer rate is 3 x 35MB/s + 1 x 29MB/s > > = 134MB/s = > > The data rate doesn't just "aggregate" like that. There is SCSI overhead > that decreases the effective overall transfer rate. Not all files are > sequential, and without spindle locking, there is quite a bit of latency. > Run some benchmarks on your system and see for your self. Also, make sure > the benchmarks AREN'T running out of disk cache...that hardly tests the disk > speed. You'll be lucky to get even near 80, if even 60. > > > the limit of a 32bit PCI bus at 133MHz (but still in the limits of an > > Adaptec 29160 controller) > > The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean > 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're > lucky. 132M bytes/sec is the burst rate. There is substantial overhead on > the PCI bus that lowers that substantially. > >
RE: filmscanners: Best solution for HD and images
> My point is that, with RAID 0, if one disk fails the data on all > the disks > is lost. And if you have one disk, and it fails, all data is lost. > Also, MTBF is additive in this case because of what I previously > said. No it is NOT. I designed RAID controllers and disk subsystems, as well as wrote and reviewed the specs for many a server, and have a lot of experience in this area. It is NOT additive at all. That is a misunderstanding of what MTBF and failure modes are.
RE: filmscanners: Best solution for HD and images
To Preben: Thanks for your response and patience. The Abit board does permit JBOD; but it does not provide RAID 5 as you have noted. When I asked about what appeared to be a contradiction between what you suggested and what the ABIT manual said I did not realize that there was a RAID 5 and that this was what you were referring to. I apologize for my ignorance; but I am not sorry I asked. Out of my asking, I learned about RAID 5, which I would not have known about if I did not raise my question about the apparent contradiction. To all who have posted on the subject of RAID: Thank you; it has been an education. I have a few additional questions that I need to be educated on and would appreciate any information that you could provide me. (1) If one sets up a RAID 0 (striping)with two 60GB disks, must each hard drive be the master on a separate IDE channel or can they be set up as master-slave on the same IDE channel? (2) If one sets up a RAID 0 (striping)with two 60GB disks under WIN 98, can one establish partitions for the array or must it be a single partition? In formatting the drives to be used in a RAID array, how does one format each of the disks with Fdisk (each disk being a brand new disk) with respect to partitions? (3)If one sets up a RAID 0 (striping)with two 60GB disks under WIN 98, can one use utilities such as ScanDisk and Disk Defragmenter on the RAID array, on individual hard drive disks in the array, or - if logical partitions are usable with the array or disks in the array - on the partitions? If this is getting to OT for the list, you can email me privately. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Preben Kristensen Sent: Sunday, November 11, 2001 3:53 PM To: [EMAIL PROTECTED] Subject: Re: filmscanners: Best solution for HD and images Hi Laurie, You basically got it right: Raid 0 or striping is putting two or more harddisks together into one bigger disk. The Raid controller and software then divides say a 55 MB file in two or more parts and writes them to the disks simultaneously. This is reversed for reading files. The pros are great speed. The cons: if one disk goes - all data on all the disks in the array is lost as well... Raid 1 or mirroring, as you said, is just an automatic backup of one disk to another disk... great security, but slow. When you combine the two you get Raid 0/1 or 10 which is data is written to several disks simultaneously and backed up automatically on a similar number of disk. Therefore the smallest number of disks in a Raid 10 is 4; 2 Raid 0 and two Raid 1 combined. JBOD is just a cluster of disks acting as one big disk - slow to write and no security. Raid 5 is like Raid 0. It writes to a number of disks simultaneously - but somehow it distributes at the same time information on all the disks - that makes it possible to recreate data should you loose one of the disks. In that case you insert a fresh harddisk and the data belonging there will be recreated. This is what I referred to as "payment for Raid 5 data security": you loose the capacity of the equivalent to one harddisk in an Raid 5 array of four disks. Ie: instead of say, 400 GB, which you would have available in a Raid 0 or 200GB in a Raid 1, you get 300GB available in a Raid 5. Because it needs to write this extra information to the disks, Raid 5 is slower than Raid 0, but your data is relatively secure. Unless, of course, you loose two harddisks at the same time from the same array. :-) The Abit KG7 Raid does not offer you the choice of Raid 5. Only 0,1 or 10 and possibly JBOD - and AFAIK nor does any of the other motherboard built-in Raid solutions. There are other and much more complicated, secure AND expensive versions of Raid. The Adaptec Website gives a very good overview: www.adaptec.com . greetings Preben - Original Message - From: "LAURIE SOLOMON" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 7:53 PM Subject: RE: filmscanners: Best solution for HD and images > Preben, > Since you seem to be knowledgeable about IDE RAID matters, I wish to make > use of your knowledge as a resource even if it is OT for this list. I > recently bought an ABIT motherboard with RAID. The manual is not very clear > as tot he difference between RAID 0 (striping) and what it does versus JBOD > (spanning). I understand what RAID 1 (mirroring) is and how it works; but I > really do not understand how RAID 0 works or what parallel operation of the > two drives on the channel means and entails. > > While it may be different for third party RAID controllers, the manual for > the RAID controller on the ABIT KG7-RAID motherboard says that you need 4 > drives to use RAID 0+1 and that the second pair duplicate the first pair. > This appears to contradict your point concerning "You "pay" the equivalent > of one d
RE: filmscanners: Best solution for HD and images
> The RAID 0 is taking half > the data and > pushing it to one hard drive, and the other half to the second, > giving you a > slight edge in speed since the bus to each hard drive can be loaded while > the other hard drive is munching on the data it just received. Not if implemented correctly. If done right, RAID 0 will get all disks worth of data in parallel (up to a certain point, depending on SCSI level, media transfer rate and system bus at a minimum)...since the media transfer rate of the disks is far less than the SCSI bus and the PCI (if used) bus. There is really no "munching", it's purely reading (or writing) an entire file...before any real "munching" is done.
Re: filmscanners: Best solution for HD and images
on 11/11/01 1:53 PM, LAURIE SOLOMON at [EMAIL PROTECTED] wrote: > Preben, > Since you seem to be knowledgeable about IDE RAID matters, I wish to make > use of your knowledge as a resource even if it is OT for this list. I > recently bought an ABIT motherboard with RAID. The manual is not very clear > as tot he difference between RAID 0 (striping) and what it does versus JBOD > (spanning). I understand what RAID 1 (mirroring) is and how it works; but I > really do not understand how RAID 0 works or what parallel operation of the > two drives on the channel means and entails. > > While it may be different for third party RAID controllers, the manual for > the RAID controller on the ABIT KG7-RAID motherboard says that you need 4 > drives to use RAID 0+1 and that the second pair duplicate the first pair. > This appears to contradict your point concerning "You "pay" the equivalent > of one drive i.e.. - in this case - 100 GB for the security of your data, > but you end up with a 300 GB drive array." If I ma reading the manual > correctly, at least on the ABIT RAID, you would have 200GB of original data > storage and 200GB duplicate mirror backup protection under the RAID 0+1 > setup - especially if you follow their advice of using same size, make, and > model of hard drive in the array. Could you comment on this in a way so as > to add some clarification for a novice to RAID arrays. > You have it exactly correct, Laurie. The RAID 0 is taking half the data and pushing it to one hard drive, and the other half to the second, giving you a slight edge in speed since the bus to each hard drive can be loaded while the other hard drive is munching on the data it just received. RAID 0+1 does exactly as you have described, striping data, but also mirroring it on a second set of drives. To use RAID effectively, both (or all) drives should ideally be of the same make and model, as even caching algorythims play a part. You can make RAID work with less than equal matches, but at a lost of capacity and speed, usually more than negating the advantage of RAID. Jim Snyder
RE: filmscanners: Best solution for HD and images
My point is that, with RAID 0, if one disk fails the data on all the disks is lost. Also, MTBF is additive in this case because of what I previously said. You've got more than one set of platters and heads to fail and any one of them failing blows away the data. I realize the chances of problems are very small but drives do still fail. My day job is architecting and administering very large database systems (1 Terabyte RAIDS) and I do see drives fail. I'd never use RAID 0 for one of these systems. For typical use though, you are right that it's very unlikely to be a problem. I just think it's kind of unnecessary unless there's a justified need for performance. Video editing would be a good example. To keep this remotely on topic, I just ordered a Minolta Scan Multi Pro. I should have it in 2 weeks. Paul Wilson > -Original Message- > From: Austin Franklin [mailto:[EMAIL PROTECTED]] > Sent: Sunday, November 11, 2001 7:40 PM > To: [EMAIL PROTECTED] > Subject: RE: filmscanners: Best solution for HD and images > > > > I just wanted to note that RAID 0 is, in most cases, a bad idea. > > The reason > > is that if you stripe your data across multiple disks and > one fails, you > > lose all the data. It's better to split the files up among > many, smaller > > logical drives. It's great from a performance standpoint > but that's about > > it. RAID 0+1 or RAID 5 are much better ideas. > > > > Paul Wilson > > I disagree that it's a bad idea. It's no more "unsafe" than > a single disk. > MTBF is NOT additive. RAID 0 IS the fastest, and if that's > what you need, > then it's a good idea. > > Also, if you are using it as a data store, which is typically > what RAID is > used for, instead of a main system disk, then you SHOULD be > backing up. > > I have dozens of hard disks in my multiple machines, and haven't had a > failure in years, and they are on 24/7/365. The MTBF of the > drives is far > less than the next technology leap that I replace the disks > for anyway. >
RE: filmscanners: Best solution for HD and images
> Thus in the case of SCSI where you cannot (by definition) overcome the > number of 6 devices x chain/controller, WHAT SCSI are you talking about? Try 16. not 6. > BTW , this method compulsorily implies a DOUBLE WRITING need i.e. > write the > data + write the new parity (even if on another disk) and this is > meaning a > LOSS OF SPEED/EFFICIENCY (relatively to the achievable speed/efficiency of > the disks) That's not true. There is no "double write", both the data/parity is written at the same time. Parity can easily be calculated on the fly. > Yesterday night I have bought on eBay an IBM U-160 1rpm 18GB new and > under warranty for 102 USD + 20$ of shipment to Italy from USA > and this unit > will be the fourth inside my system while having 2 x CD/R (IDE) > and 1 x DVD > (IDE) . > My aggregated sustained transfer rate is 3 x 35MB/s + 1 x 29MB/s > = 134MB/s = The data rate doesn't just "aggregate" like that. There is SCSI overhead that decreases the effective overall transfer rate. Not all files are sequential, and without spindle locking, there is quite a bit of latency. Run some benchmarks on your system and see for your self. Also, make sure the benchmarks AREN'T running out of disk cache...that hardly tests the disk speed. You'll be lucky to get even near 80, if even 60. > the limit of a 32bit PCI bus at 133MHz (but still in the limits of an > Adaptec 29160 controller) The standard PCI bus is 33 MHz (or 66MHz), NOT 133MHz. Perhaps you mean 132M BYTES/sec? Even at that, you can't get near %80 of that, if you're lucky. 132M bytes/sec is the burst rate. There is substantial overhead on the PCI bus that lowers that substantially.
RE: filmscanners: RE: filmscanners: Best solution for HD and images
> Also consider that striping doubles your chances of losing your > data NO it does not. MTBF is NOT additive. Whether you have 1 or 100 devices that have a MTBF of 10,000 hours, the MTBF of the system is still 10,000 hours.
RE: filmscanners: Best solution for HD and images
--- Austin Franklin <[EMAIL PROTECTED]> wrote: > > I just wanted to note that RAID 0 is, in most cases, a bad idea. > > The reason > > is that if you stripe your data across multiple disks and one > fails, you > > lose all the data. It's better to split the files up among many, > smaller > > logical drives. It's great from a performance standpoint but > that's about > > it. RAID 0+1 or RAID 5 are much better ideas. > > > > Paul Wilson > > I disagree that it's a bad idea. It's no more "unsafe" than a single > disk. > MTBF is NOT additive. RAID 0 IS the fastest, and if that's what you > need, > then it's a good idea. It *IS* more unsafe to use RAID0. And MTBF *IS* additive. Actually, more exactly it is reduced and not increased. If you have 1 drive with a MTBF of 10 hours you can expect an error every 10 hours in average. If you have 4 drives each with an MTBF of 10 then your MTBF of your RAID0 system is 10/4=25000 hours, i.e. in your RAID0 system an error will occur every 25000 hours in average and such an error will be disasterous for the whole RAID0 sytem. The abve does not take into account failures due to over-surge, earthquakes, etc in which case MTBF is not linear. But MTBF for an individual HD does not take these kind of events into account either. Anyway, 25000 hours is almost 3 years. Taking into account that with most home systems you don't use more then 2 drives, that with many solutions you don't gain much speed with more then 2 drives, and that the MTBF can be considerable higher a failure is even much more unlikely. Therefore, with some backup, RAID 0 is still a good solution if you want to have higher speed. This is especially true if you work with big files. 50 MBytes image files already take quite a while to store an a regular system. When you work with files that have multiple 100 MBytes then a RAID0 system is sure quite helpful. Robert __ Do You Yahoo!? Find a job, post your resume. http://careers.yahoo.com
filmscanners: Re: filmscanners: Best solution for HD and images
Ezio wrote: >I really cannot understand why it would be needed such a complication and >dependancy from the controller vendor when the SCSI hard drives cost almost >the same (or 20% more max) of IDE hard drives ! Ezio, I know we've been here before, but SCSI isn't a cheap option for everyone. Certainly, if I was in the US and had access to the sorts of prices you quote from ebay, I'd use SCSI... well, there's other problems. If I wanted to use a 10Krpm SCSI drive I'd also have to fit a cooling fan in my computer and move house to somewhere that had air-conditioning. I simply couldn't run such hard drives in 30+C temperatures reliably. I can buy two 7200rpm IDE drives locally for about US$250, plus another US$45 for an IDE RAID controller. The SCSI option (in Australia) would cost me US$200 for the SCSI controller card, and at least US$500 for an equivalent capacity 10Krpm SCSI drive. Plus, the IDE drives would behave themselves more reliably outside of an airconditioned office. Obscanning: on a completely different topic, I've just taken a roll of Provia 100F using two L series Canon lenses. I should get back the results tomorrow so I can get an idea of how much difference the lenses made in scanning on the LS30. Rob PS I got two more of my photos on the magazine cover. Scanned with the LS30 and they look great! :) Rob Geraghty [EMAIL PROTECTED] http://wordweb.com
filmscanners: RE: filmscanners: Best solution for HD and images
Paul wrote: > I just wanted to note that RAID 0 is, in most cases, > a bad idea. The reason is that if you stripe your > data across multiple disks and one fails, you > lose all the data. This is true - however most of us rely on one hard drive for *everything*. Striping across two drives gives you much greater speed with no significant difference in reliability (and yes I know there's two devices involved). Personally I copy my data to CDR, and if the hard drive dies I'll have to rebuild the OS from scratch. There's better options, but the cost and hassle isn't worth it for me. I'd rather be running a two drive stripe set and halve the time I sit around waiting to load and save 27MB film scans. If you can afford the number of drives required to get to RAID 0/1 or 5, go for it. Rob PS Can someone confirm for me that all this discussion of IDE RAID is irrelevent to Mac users? Are there IDE RAID solutions for Mac? Rob Geraghty [EMAIL PROTECTED] http://wordweb.com
Re: filmscanners: RE: filmscanners: Best solution for HD and images
- Original Message - From: "Rob Geraghty" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 10:53 PM Subject: filmscanners: RE: filmscanners: Best solution for HD and images > > IMO the higher RAID types are fine for servers, but not worth the hassle > for home use. I think for home/SOHO use with film scanning, go for striping > to get the speed and if you're worried about security, get a tape drive > for backup. I would agree this would seem to be the best solution for PS temporary files and image scans that have the original film as backup. Also consider that striping doubles your chances of losing your data (EITHER drive failing will lose ALL your data). Data access times are roughly the same as a single drive it is only the transfer rate that doubles (the most important bit for large data transfers like film scans). With some mirrored controllers only writing is slower. Read operations can be striped if the hardware/software implementation is clever enough. On average you read files more often than you write so with a smart controller you get very slightly slower writes, but almost double the transfer rates during reads. Steve
RE: filmscanners: Best solution for HD and images
> I just wanted to note that RAID 0 is, in most cases, a bad idea. > The reason > is that if you stripe your data across multiple disks and one fails, you > lose all the data. It's better to split the files up among many, smaller > logical drives. It's great from a performance standpoint but that's about > it. RAID 0+1 or RAID 5 are much better ideas. > > Paul Wilson I disagree that it's a bad idea. It's no more "unsafe" than a single disk. MTBF is NOT additive. RAID 0 IS the fastest, and if that's what you need, then it's a good idea. Also, if you are using it as a data store, which is typically what RAID is used for, instead of a main system disk, then you SHOULD be backing up. I have dozens of hard disks in my multiple machines, and haven't had a failure in years, and they are on 24/7/365. The MTBF of the drives is far less than the next technology leap that I replace the disks for anyway.
Re: filmscanners: Best solution for HD and images
Pat , you are right . Please, let me add some comments while OT ... I think this matter of efficiency and speed is an argument directly involving our group seen that e-photography is meaning big amounts of data and (eventually) long waitings in front of a screen . >The Adaptec RAID >card works somewhat differently and allows multiple >channels to behave as one. Raid 5 then can be thought >of as n number of disks with the data striped as in >Raid 0, but with parity error information saved along >with the data. The amount of redundant data used is >1/n, so the total amount of storage is (drive >capacity)*(n-1). As far as I know this is the definition of RAID 5 with the distribution = sharing of the so called ''check sum / parity'' byte on the disk chain ! Be careful because in case of multiple chains you will need multiple spare areas (as many as the chains). Thus in the case of SCSI where you cannot (by definition) overcome the number of 6 devices x chain/controller, you will have , as a minimum , 100/6 = 12.7% used by the parity and then 87.3% of AVAILABLE space for the user LESS what it is taken by the stack from the theoretical capacity of the disks. BTW , this method compulsorily implies a DOUBLE WRITING need i.e. write the data + write the new parity (even if on another disk) and this is meaning a LOSS OF SPEED/EFFICIENCY (relatively to the achievable speed/efficiency of the disks) relatively to other RAID techniques like RAID 1 RAID 0 is (by definition) the opposite side of the domain i.e. full speed/efficiency but NOT SAFETY (as you correctly state). AFAIK, more over , to overcome the ineherent limitation of IDE protocol and be able to put more than 2 devices x controller , the vendor has to multiply (internally to the disk controller) the number of IDE controllers and rejoin everything to the ''image'' of a single virtual controller and so on I really cannot understand why it would be needed such a complication and dependancy from the controller vendor when the SCSI hard drives cost almost the same (or 20% more max) of IDE hard drives ! Sometime ago the difference was remarquable and then people not willing to have large amount of data available at workstation level were trading off speed + efficiency + safety with a cheap hard drive but today ? ... an IDE RAID (or array) controller costs more/same as a good SCSI controller , providing less speed , less functions , less efficiency and less safety . Is it a matter of principles ? Yesterday night I have bought on eBay an IBM U-160 1rpm 18GB new and under warranty for 102 USD + 20$ of shipment to Italy from USA and this unit will be the fourth inside my system while having 2 x CD/R (IDE) and 1 x DVD (IDE) . My aggregated sustained transfer rate is 3 x 35MB/s + 1 x 29MB/s = 134MB/s = the limit of a 32bit PCI bus at 133MHz (but still in the limits of an Adaptec 29160 controller) Sorry , but I cannot perceive the price/performance advantage of an IDE solution . Not even in the case of a lower amount of data requested. Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "Pat Perez" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 10:00 PM Subject: RE: filmscanners: Best solution for HD and images > I'll jump in here. > > Raid 0, striping, assigns half of the data to one > drive, the other half to the other drive. The writes > happen more or less simultaneuosly, so large file > operations happen in roughly half the time. > > Raid 1 is, as you said, mirroring, where all data are > duplicated, so that if a drive fails, another exact > copy is ready to take over (after a command to 'break' > the mirror set). > > Classically, Raid 5 has a single chain logically (IDE > is limited to 2 devices per chain, and the above have > both drives on one chain (channel)). The Adaptec RAID > card works somewhat differently and allows multiple > channels to behave as one. Raid 5 then can be thought > of as n number of disks with the data striped as in > Raid 0, but with parity error information saved along > with the data. The amount of redundant data used is > 1/n, so the total amount of storage is (drive > capacity)*(n-1). > > Raid 0+1 is an IDE only hybrod that allows you to use > both channels with two disks such that you get > mirroring of two striped disks. > > I know of no motherboard based IDE Raid solutions that > are designed for high performance (Preben mentioned > that the host CPU does the drive I/O processing). > Apparently, the Adaptec IDE Raid PCI card handles > this. I have no experience with this card (though I > use Adaptec SCSI adapters exclusively). At work I have > a card similar to what Preben described. It is made by > 3Ware (www.3ware.com), and i
RE: filmscanners: Best solution for HD and images
I just wanted to note that RAID 0 is, in most cases, a bad idea. The reason is that if you stripe your data across multiple disks and one fails, you lose all the data. It's better to split the files up among many, smaller logical drives. It's great from a performance standpoint but that's about it. RAID 0+1 or RAID 5 are much better ideas. Paul Wilson > -Original Message- > From: Robert Meier [mailto:[EMAIL PROTECTED]] > Sent: Sunday, November 11, 2001 4:25 PM > To: [EMAIL PROTECTED] > Subject: RE: filmscanners: Best solution for HD and images > > > Laurie, > > spanning: The drives are cascaded. So if you have a 60GB and 80GB HD > you get a 140GB HD. Except that you are able to see one big > HD there is > no advantage regarding speed, etc. > > striping: Puts drives in parallel configuration. The smallest > HD limits > the capacity. For example if you have a 60GB and 80GB HD then > the total > capacity will be 60GB*2=120GB. The advantage is that you can almost > double the sustained read/write speed. This is only true if the drives > are on seperate IDE channels. Most motherboards have two independent > channels. In this configuration you are best off using two identical > HDs. > > mirroring: Writes the same data on two different drives. So when one > goes bad you can replace it with the other. You don't gain > any capacity > or speed if it is not combined with any of the above techniques (which > then will require more then 2 HDs). > > If you have raid0+1 you use striping and mirroring. So if you have 4 > 60GB HDs you would have 240GB with striping (RAID0) only. But > since you > use also mirroring (RAID1) the capacity is only half of it to keep a > copy of all the data you have -> 120GB > > Robert > > --- LAURIE SOLOMON <[EMAIL PROTECTED]> wrote: > > Preben, > > Since you seem to be knowledgeable about IDE RAID matters, I wish to > > make > > use of your knowledge as a resource even if it is OT for this list. > > I > > recently bought an ABIT motherboard with RAID. The manual is not > > very clear > > as tot he difference between RAID 0 (striping) and what it does > > versus JBOD > > (spanning). I understand what RAID 1 (mirroring) is and how it > > works; but I > > really do not understand how RAID 0 works or what parallel operation > > of the > > two drives on the channel means and entails. > > > > While it may be different for third party RAID controllers, the > > manual for > > the RAID controller on the ABIT KG7-RAID motherboard says that you > > need 4 > > drives to use RAID 0+1 and that the second pair duplicate the first > > pair. > > This appears to contradict your point concerning "You "pay" the > > equivalent > > of one drive i.e.. - in this case - 100 GB for the security of your > > data, > > but you end up with a 300 GB drive array." If I ma reading the > > manual > > correctly, at least on the ABIT RAID, you would have 200GB of > > original data > > storage and 200GB duplicate mirror backup protection under the RAID > > 0+1 > > setup - especially if you follow their advice of using same size, > > make, and > > model of hard drive in the array. Could you comment on > this in a way > > so as > > to add some clarification for a novice to RAID arrays. > > > > > > -Original Message- > > From: [EMAIL PROTECTED] > > [mailto:[EMAIL PROTECTED]]On Behalf Of Preben > > Kristensen > > Sent: Sunday, November 11, 2001 5:35 AM > > To: [EMAIL PROTECTED] > > Subject: Re: filmscanners: Best solution for HD and images > > > > > > IMO the best price/performance/data safety setup is IDE Raid 5. If > > you buy a > > Ide Raid 5 card (Adaptec makes a good one: 2400A, which sells for > > around 300 > > US) you can then connect, say four IDE 100GB drives and get an array > > which > > is very fast AND fairly fault tolerant. You "pay" the equivalent of > > one > > drive ie. - in this case - 100 GB for the security of your data, but > > you end > > up with a 300 GB drive array and the ability to > swap/hotswap a drive > > and > > rebuild the array should one of the drives fail. > > > > Also, by using UDMA/100 5400 instead of 7200 drives you get a > > slightly > > slover performance, but you gain by having much lower temperatures > > and much > > lower noise levels. > > > > Such a Raid 5 system would cost around 1300 US (depending where you > > buy) for > > 300 GB, but your d
filmscanners: RE: filmscanners: Best solution for HD and images
Laurie wrote: > (spanning). I understand what RAID 1 (mirroring) is and how > it works; but I really do not understand how RAID 0 works or > what parallel operation of the two drives on the channel means > and entails. Striping simply means that data is interleaved on different disks. In a simple two disk stripe set, you interleave between two drives. When the file is read or written, you're using both drives, so (in an ideal world) you get twice the speed of a single drive. In practice it's not quite double, but it can be close. >While it may be different for third party RAID controllers, the manual for >the RAID controller on the ABIT KG7-RAID motherboard says that you need 4 >drives to use RAID 0+1 and that the second pair duplicate the first pair. In RAID 0/1 you have four drives - two sets of interleaved drives, with the data mirrored between the pairs. So you get the speed increase of striping plus the security of mirroring *but* you lose storage space by mirroring. If you have two 20GB disks interleaved, you get 40GB of storage with almost double the speed. Mirrored you have normal speed but greater security. To get the combination you have the expense of four 20GB drives giving you 40GB storage with security and speed. A better system with multiple drives is RAID5 where you have "parity" - it's a bit complicated to explain but in RAID5 any of the drives can go down and you can rebuild the data from the other drives. This sort of thing tends to be expensive to set up, just like 0/1! IMO the higher RAID types are fine for servers, but not worth the hassle for home use. I think for home/SOHO use with film scanning, go for striping to get the speed and if you're worried about security, get a tape drive for backup. Rob Rob Geraghty [EMAIL PROTECTED] http://wordweb.com
Re: filmscanners: Best solution for HD and images
Hi Laurie, You basically got it right: Raid 0 or striping is putting two or more harddisks together into one bigger disk. The Raid controller and software then divides say a 55 MB file in two or more parts and writes them to the disks simultaneously. This is reversed for reading files. The pros are great speed. The cons: if one disk goes - all data on all the disks in the array is lost as well... Raid 1 or mirroring, as you said, is just an automatic backup of one disk to another disk... great security, but slow. When you combine the two you get Raid 0/1 or 10 which is data is written to several disks simultaneously and backed up automatically on a similar number of disk. Therefore the smallest number of disks in a Raid 10 is 4; 2 Raid 0 and two Raid 1 combined. JBOD is just a cluster of disks acting as one big disk - slow to write and no security. Raid 5 is like Raid 0. It writes to a number of disks simultaneously - but somehow it distributes at the same time information on all the disks - that makes it possible to recreate data should you loose one of the disks. In that case you insert a fresh harddisk and the data belonging there will be recreated. This is what I referred to as "payment for Raid 5 data security": you loose the capacity of the equivalent to one harddisk in an Raid 5 array of four disks. Ie: instead of say, 400 GB, which you would have available in a Raid 0 or 200GB in a Raid 1, you get 300GB available in a Raid 5. Because it needs to write this extra information to the disks, Raid 5 is slower than Raid 0, but your data is relatively secure. Unless, of course, you loose two harddisks at the same time from the same array. :-) The Abit KG7 Raid does not offer you the choice of Raid 5. Only 0,1 or 10 and possibly JBOD - and AFAIK nor does any of the other motherboard built-in Raid solutions. There are other and much more complicated, secure AND expensive versions of Raid. The Adaptec Website gives a very good overview: www.adaptec.com . greetings Preben - Original Message - From: "LAURIE SOLOMON" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 7:53 PM Subject: RE: filmscanners: Best solution for HD and images > Preben, > Since you seem to be knowledgeable about IDE RAID matters, I wish to make > use of your knowledge as a resource even if it is OT for this list. I > recently bought an ABIT motherboard with RAID. The manual is not very clear > as tot he difference between RAID 0 (striping) and what it does versus JBOD > (spanning). I understand what RAID 1 (mirroring) is and how it works; but I > really do not understand how RAID 0 works or what parallel operation of the > two drives on the channel means and entails. > > While it may be different for third party RAID controllers, the manual for > the RAID controller on the ABIT KG7-RAID motherboard says that you need 4 > drives to use RAID 0+1 and that the second pair duplicate the first pair. > This appears to contradict your point concerning "You "pay" the equivalent > of one drive i.e.. - in this case - 100 GB for the security of your data, > but you end up with a 300 GB drive array." If I ma reading the manual > correctly, at least on the ABIT RAID, you would have 200GB of original data > storage and 200GB duplicate mirror backup protection under the RAID 0+1 > setup - especially if you follow their advice of using same size, make, and > model of hard drive in the array. Could you comment on this in a way so as > to add some clarification for a novice to RAID arrays. > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Preben Kristensen > Sent: Sunday, November 11, 2001 5:35 AM > To: [EMAIL PROTECTED] > Subject: Re: filmscanners: Best solution for HD and images > > > IMO the best price/performance/data safety setup is IDE Raid 5. If you buy a > Ide Raid 5 card (Adaptec makes a good one: 2400A, which sells for around 300 > US) you can then connect, say four IDE 100GB drives and get an array which > is very fast AND fairly fault tolerant. You "pay" the equivalent of one > drive ie. - in this case - 100 GB for the security of your data, but you end > up with a 300 GB drive array and the ability to swap/hotswap a drive and > rebuild the array should one of the drives fail. > > Also, by using UDMA/100 5400 instead of 7200 drives you get a slightly > slover performance, but you gain by having much lower temperatures and much > lower noise levels. > > Such a Raid 5 system would cost around 1300 US (depending where you buy) for > 300 GB, but your data is much more secure than the simpler and cheaper Raid > 0. > > Lastly, these stand alone Raid cards - unlike raid solutions on > motherbords - have their own processors on board
RE: filmscanners: Best solution for HD and images
I'll jump in here. Raid 0, striping, assigns half of the data to one drive, the other half to the other drive. The writes happen more or less simultaneuosly, so large file operations happen in roughly half the time. Raid 1 is, as you said, mirroring, where all data are duplicated, so that if a drive fails, another exact copy is ready to take over (after a command to 'break' the mirror set). Classically, Raid 5 has a single chain logically (IDE is limited to 2 devices per chain, and the above have both drives on one chain (channel)). The Adaptec RAID card works somewhat differently and allows multiple channels to behave as one. Raid 5 then can be thought of as n number of disks with the data striped as in Raid 0, but with parity error information saved along with the data. The amount of redundant data used is 1/n, so the total amount of storage is (drive capacity)*(n-1). Raid 0+1 is an IDE only hybrod that allows you to use both channels with two disks such that you get mirroring of two striped disks. I know of no motherboard based IDE Raid solutions that are designed for high performance (Preben mentioned that the host CPU does the drive I/O processing). Apparently, the Adaptec IDE Raid PCI card handles this. I have no experience with this card (though I use Adaptec SCSI adapters exclusively). At work I have a card similar to what Preben described. It is made by 3Ware (www.3ware.com), and is called the Escalade. I can heartily recommend this card under Win2000, the only OS I have used it with. It is available with support for 2, 4, or 8 IDE drives. At this time, it doesn't yet support the new ATA133, so I guess you'd be limited to 8 of Maxtor's 100 gigabyte drives! There are actually several other levels of RAID, but they are mathematically undesirable as regards the cost/benefit/performance tradeoffs. For performance, striping offers the best value. But it also offers no protection for your data, so is only desirable when data safety is not mandatory. Otherwise, RAID 5 is the best combination of safety and performance. Pat --- LAURIE SOLOMON <[EMAIL PROTECTED]> wrote: > Preben, > Since you seem to be knowledgeable about IDE RAID > matters, I wish to make > use of your knowledge as a resource even if it is OT > for this list. I > recently bought an ABIT motherboard with RAID. The > manual is not very clear > as tot he difference between RAID 0 (striping) and > what it does versus JBOD > (spanning). I understand what RAID 1 (mirroring) is > and how it works; but I > really do not understand how RAID 0 works or what > parallel operation of the > two drives on the channel means and entails. > > While it may be different for third party RAID > controllers, the manual for > the RAID controller on the ABIT KG7-RAID motherboard > says that you need 4 > drives to use RAID 0+1 and that the second pair > duplicate the first pair. > This appears to contradict your point concerning > "You "pay" the equivalent > of one drive i.e.. - in this case - 100 GB for the > security of your data, > but you end up with a 300 GB drive array." If I ma > reading the manual > correctly, at least on the ABIT RAID, you would have > 200GB of original data > storage and 200GB duplicate mirror backup protection > under the RAID 0+1 > setup - especially if you follow their advice of > using same size, make, and > model of hard drive in the array. Could you comment > on this in a way so as > to add some clarification for a novice to RAID > arrays. > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf > Of Preben Kristensen > Sent: Sunday, November 11, 2001 5:35 AM > To: [EMAIL PROTECTED] > Subject: Re: filmscanners: Best solution for HD and > images > > > IMO the best price/performance/data safety setup is > IDE Raid 5. If you buy a > Ide Raid 5 card (Adaptec makes a good one: 2400A, > which sells for around 300 > US) you can then connect, say four IDE 100GB drives > and get an array which > is very fast AND fairly fault tolerant. You "pay" > the equivalent of one > drive ie. - in this case - 100 GB for the security > of your data, but you end > up with a 300 GB drive array and the ability to > swap/hotswap a drive and > rebuild the array should one of the drives fail. > > Also, by using UDMA/100 5400 instead of 7200 drives > you get a slightly > slover performance, but you gain by having much > lower temperatures and much > lower noise levels. > > Such a Raid 5 system would cost around 1300 US > (depending where you buy) for > 300 GB, but your data is much more secure than the > simpler and cheaper Raid > 0. > > Lastly, these stand alone Raid cards - unlike raid > solutions on
RE: filmscanners: Best solution for HD and images
Laurie, spanning: The drives are cascaded. So if you have a 60GB and 80GB HD you get a 140GB HD. Except that you are able to see one big HD there is no advantage regarding speed, etc. striping: Puts drives in parallel configuration. The smallest HD limits the capacity. For example if you have a 60GB and 80GB HD then the total capacity will be 60GB*2=120GB. The advantage is that you can almost double the sustained read/write speed. This is only true if the drives are on seperate IDE channels. Most motherboards have two independent channels. In this configuration you are best off using two identical HDs. mirroring: Writes the same data on two different drives. So when one goes bad you can replace it with the other. You don't gain any capacity or speed if it is not combined with any of the above techniques (which then will require more then 2 HDs). If you have raid0+1 you use striping and mirroring. So if you have 4 60GB HDs you would have 240GB with striping (RAID0) only. But since you use also mirroring (RAID1) the capacity is only half of it to keep a copy of all the data you have -> 120GB Robert --- LAURIE SOLOMON <[EMAIL PROTECTED]> wrote: > Preben, > Since you seem to be knowledgeable about IDE RAID matters, I wish to > make > use of your knowledge as a resource even if it is OT for this list. > I > recently bought an ABIT motherboard with RAID. The manual is not > very clear > as tot he difference between RAID 0 (striping) and what it does > versus JBOD > (spanning). I understand what RAID 1 (mirroring) is and how it > works; but I > really do not understand how RAID 0 works or what parallel operation > of the > two drives on the channel means and entails. > > While it may be different for third party RAID controllers, the > manual for > the RAID controller on the ABIT KG7-RAID motherboard says that you > need 4 > drives to use RAID 0+1 and that the second pair duplicate the first > pair. > This appears to contradict your point concerning "You "pay" the > equivalent > of one drive i.e.. - in this case - 100 GB for the security of your > data, > but you end up with a 300 GB drive array." If I ma reading the > manual > correctly, at least on the ABIT RAID, you would have 200GB of > original data > storage and 200GB duplicate mirror backup protection under the RAID > 0+1 > setup - especially if you follow their advice of using same size, > make, and > model of hard drive in the array. Could you comment on this in a way > so as > to add some clarification for a novice to RAID arrays. > > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Preben > Kristensen > Sent: Sunday, November 11, 2001 5:35 AM > To: [EMAIL PROTECTED] > Subject: Re: filmscanners: Best solution for HD and images > > > IMO the best price/performance/data safety setup is IDE Raid 5. If > you buy a > Ide Raid 5 card (Adaptec makes a good one: 2400A, which sells for > around 300 > US) you can then connect, say four IDE 100GB drives and get an array > which > is very fast AND fairly fault tolerant. You "pay" the equivalent of > one > drive ie. - in this case - 100 GB for the security of your data, but > you end > up with a 300 GB drive array and the ability to swap/hotswap a drive > and > rebuild the array should one of the drives fail. > > Also, by using UDMA/100 5400 instead of 7200 drives you get a > slightly > slover performance, but you gain by having much lower temperatures > and much > lower noise levels. > > Such a Raid 5 system would cost around 1300 US (depending where you > buy) for > 300 GB, but your data is much more secure than the simpler and > cheaper Raid > 0. > > Lastly, these stand alone Raid cards - unlike raid solutions on > motherbords - have their own processors on board which takes over > all the > hard work, freeing up your system processor. > > GreetingsPreben > > > - Original Message - > From: "James Grove" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Sunday, November 11, 2001 9:46 AM > Subject: RE: filmscanners: Best solution for HD and images > > > > I have just ordered a 60 Gig Maxtor ATA 100 drive (ATA 133 is also > > available) I have done this because it is far cheaper than buying > > another 36 gig drive to go on my U160 SCSI channel. I can get the > Maxtor > > drives for around 60 UK pounds, which means I could buy 4 of these > IDE > > drives for the same price as a Quantum U160 36gig drive! > > > > One thing to remember about Ide if you decide to give the drive a > > beasting is to cool it with a slim cooler. > > > > -- &g
RE: filmscanners: Best solution for HD and images
Preben, Since you seem to be knowledgeable about IDE RAID matters, I wish to make use of your knowledge as a resource even if it is OT for this list. I recently bought an ABIT motherboard with RAID. The manual is not very clear as tot he difference between RAID 0 (striping) and what it does versus JBOD (spanning). I understand what RAID 1 (mirroring) is and how it works; but I really do not understand how RAID 0 works or what parallel operation of the two drives on the channel means and entails. While it may be different for third party RAID controllers, the manual for the RAID controller on the ABIT KG7-RAID motherboard says that you need 4 drives to use RAID 0+1 and that the second pair duplicate the first pair. This appears to contradict your point concerning "You "pay" the equivalent of one drive i.e.. - in this case - 100 GB for the security of your data, but you end up with a 300 GB drive array." If I ma reading the manual correctly, at least on the ABIT RAID, you would have 200GB of original data storage and 200GB duplicate mirror backup protection under the RAID 0+1 setup - especially if you follow their advice of using same size, make, and model of hard drive in the array. Could you comment on this in a way so as to add some clarification for a novice to RAID arrays. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of Preben Kristensen Sent: Sunday, November 11, 2001 5:35 AM To: [EMAIL PROTECTED] Subject: Re: filmscanners: Best solution for HD and images IMO the best price/performance/data safety setup is IDE Raid 5. If you buy a Ide Raid 5 card (Adaptec makes a good one: 2400A, which sells for around 300 US) you can then connect, say four IDE 100GB drives and get an array which is very fast AND fairly fault tolerant. You "pay" the equivalent of one drive ie. - in this case - 100 GB for the security of your data, but you end up with a 300 GB drive array and the ability to swap/hotswap a drive and rebuild the array should one of the drives fail. Also, by using UDMA/100 5400 instead of 7200 drives you get a slightly slover performance, but you gain by having much lower temperatures and much lower noise levels. Such a Raid 5 system would cost around 1300 US (depending where you buy) for 300 GB, but your data is much more secure than the simpler and cheaper Raid 0. Lastly, these stand alone Raid cards - unlike raid solutions on motherbords - have their own processors on board which takes over all the hard work, freeing up your system processor. GreetingsPreben - Original Message - From: "James Grove" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 9:46 AM Subject: RE: filmscanners: Best solution for HD and images > I have just ordered a 60 Gig Maxtor ATA 100 drive (ATA 133 is also > available) I have done this because it is far cheaper than buying > another 36 gig drive to go on my U160 SCSI channel. I can get the Maxtor > drives for around 60 UK pounds, which means I could buy 4 of these IDE > drives for the same price as a Quantum U160 36gig drive! > > One thing to remember about Ide if you decide to give the drive a > beasting is to cool it with a slim cooler. > > -- > James Grove > [EMAIL PROTECTED] > www.jamesgrove.co.uk > www.mountain-photos.co.uk > ICQ 99737573 > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]] On Behalf Of Ezio c/o TIN > Sent: 10 November 2001 21:18 > To: [EMAIL PROTECTED] > Subject: Re: filmscanners: Best solution for HD and images > > > I would recommend to buy a U-160 SCSI ... from e-bay ... I have just > done this to integrate the other 3 U-160 I have and I have bought for > 102US $ a 18GB IBM 1 rpm brand new under warranty. A 36GB 1rpm > also IBM U-160 is rated for 170 US $ ... > > Sincerely. > > Ezio > > www.lucenti.com e-photography site > > > - Original Message - > From: "Andrea de Polo" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Saturday, November 10, 2001 4:53 PM > Subject: filmscanners: Best solution for HD and images > > > > Hello, > > > > I have a CreoScitex scanner with attached a, Apple G4 Silver 733 with > > OS > 9.2.1 and 1GB of ram; I noticed that the internal HD is a slow 5400rpm > UltraAta HD; question: since I work only with Photoshop and my images > are about 60mb in size and I just have to open and save them during the > day (we process about 200 images/day), I was wondering what is the best > and effective way to speed up my work: buy a scsi external HD 10.000rpm > (total cost about 650 UK pounds), OR buy an internal UltraAta 7200 rpm > (total cost about 250 UK pounds) ??? > > > > Again, we just have to open, retouch and than save our
Re: filmscanners: Best solution for HD and images
Sorry to say negative , you can use an adapter you can buy for 10$ at any shop . It will transform 80 pin SCA to 68 pin SCSI 3 I have already 3 IBM SCA transformed to 68pin installed in the system I am using to write this note. SCA is the standard providing the power supply together with USCSI signal ... if you don't have a rack already then the adapter will solve. Anyway , the need of an adapter is not changing the meaning of what I am stating. Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "Tom Scales" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 3:03 PM Subject: Re: filmscanners: Best solution for HD and images > This is an 80-pin, meant to be put in a rack mount. You can get an adapter, > but you're limited in the number of drives you can use in a chain with > adapters and the adapters are about $25. > > Better to find a 68pin. > > Tom > From: "Ezio c/o TIN" > > > Quantum 10KRPM 18GB ultra160 Scsi Raid DUTCH > > Item # 1295572989 > > > > NO COMMENTS !! > > > > > > This auction is for 5 pieces of NEW 1" Quantum 18GB ultra160 Scsi Raid SCA > > 80 pin interface, 10,000RPM LVD/SE scsi hardrives > > > >
Re: filmscanners: Best solution for HD and images
This is an 80-pin, meant to be put in a rack mount. You can get an adapter, but you're limited in the number of drives you can use in a chain with adapters and the adapters are about $25. Better to find a 68pin. Tom From: "Ezio c/o TIN" > Quantum 10KRPM 18GB ultra160 Scsi Raid DUTCH > Item # 1295572989 > > NO COMMENTS !! > > This auction is for 5 pieces of NEW 1" Quantum 18GB ultra160 Scsi Raid SCA > 80 pin interface, 10,000RPM LVD/SE scsi hardrives >
Re: filmscanners: Best solution for HD and images
Quantum 10KRPM 18GB ultra160 Scsi Raid DUTCH Item # 1295572989 NO COMMENTS !! Computers:Drives, Media:Drives:Hard Drives-SCSI Currently $75.00 First bid $75.00 Quantity 5 # of bids 1 bid history Time left 3 days, 4 hours + Location SILICON VALLEY Country/Region USA/San Jose Started Nov-09-01 10:27:45 PST mail this auction to a friend Ends Nov-14-01 10:27:45 PST watch this item Seller (Rating) luckyunme2aw (139) view comments in seller's Feedback Profile | view seller's other auctions | ask seller a question High bid see winning bidders list (include e-mails) Payment See item description for payment methods accepted Shipping Will ship to United States only. See item description for shipping charges. Seller assumes all responsibility for listing this item. You should contact the seller to resolve any questions before bidding. Auction currency is U.S. dollars ( $ ) unless otherwise noted. Description This auction is for 5 pieces of NEW 1" Quantum 18GB ultra160 Scsi Raid SCA 80 pin interface, 10,000RPM LVD/SE scsi hardrives Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "James Grove" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 9:46 AM Subject: RE: filmscanners: Best solution for HD and images > I have just ordered a 60 Gig Maxtor ATA 100 drive (ATA 133 is also > available) I have done this because it is far cheaper than buying > another 36 gig drive to go on my U160 SCSI channel. I can get the Maxtor > drives for around 60 UK pounds, which means I could buy 4 of these IDE > drives for the same price as a Quantum U160 36gig drive! > > One thing to remember about Ide if you decide to give the drive a > beasting is to cool it with a slim cooler. > > -- > James Grove > [EMAIL PROTECTED] > www.jamesgrove.co.uk > www.mountain-photos.co.uk > ICQ 99737573 > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]] On Behalf Of Ezio c/o TIN > Sent: 10 November 2001 21:18 > To: [EMAIL PROTECTED] > Subject: Re: filmscanners: Best solution for HD and images > > > I would recommend to buy a U-160 SCSI ... from e-bay ... I have just > done this to integrate the other 3 U-160 I have and I have bought for > 102US $ a 18GB IBM 1 rpm brand new under warranty. A 36GB 1rpm > also IBM U-160 is rated for 170 US $ ... > > Sincerely. > > Ezio > > www.lucenti.com e-photography site > > > - Original Message - > From: "Andrea de Polo" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Saturday, November 10, 2001 4:53 PM > Subject: filmscanners: Best solution for HD and images > > > > Hello, > > > > I have a CreoScitex scanner with attached a, Apple G4 Silver 733 with > > OS > 9.2.1 and 1GB of ram; I noticed that the internal HD is a slow 5400rpm > UltraAta HD; question: since I work only with Photoshop and my images > are about 60mb in size and I just have to open and save them during the > day (we process about 200 images/day), I was wondering what is the best > and effective way to speed up my work: buy a scsi external HD 10.000rpm > (total cost about 650 UK pounds), OR buy an internal UltraAta 7200 rpm > (total cost about 250 UK pounds) ??? > > > > Again, we just have to open, retouch and than save our 40mb images, > > but > currently I am noticing that is taking a bit to access the HD. > > > > Thanks to give me your best solution for time/money issue. Andrea > > -- > > > > Fratelli Alinari Photo Archives and Museum > > http://www.alinari.com > > The world's oldest picture library > > tel: +39-055-2395201 > > gsm: +39-347-4883223 > > fax: +39-055-2382857 > > > > > > >
Re: filmscanners: Best solution for HD and images
"Andrea de Polo" <[EMAIL PROTECTED]> wrote: > I have a CreoScitex scanner with attached a, Apple G4 Silver 733 with OS 9.2.1 and 1GB of ram; > I noticed that the internal HD is a slow 5400rpm UltraAta HD; question: since I work only with > Photoshop and my images are about 60mb in size and I just have to open and save them during > the day (we process about 200 images/day), I was wondering what is the best and effective way > to speed up my work: buy a scsi external HD 10.000rpm (total cost about 650 UK pounds), OR > buy an internal UltraAta 7200 rpm (total cost about 250 UK pounds) ??? I was going to suggest an IDE RAID card but then I noticed you were talking a Mac. Under those circumstances the SCSI drive is probably the best option. Rob
Re: filmscanners: Best solution for HD and images
IMO the best price/performance/data safety setup is IDE Raid 5. If you buy a Ide Raid 5 card (Adaptec makes a good one: 2400A, which sells for around 300 US) you can then connect, say four IDE 100GB drives and get an array which is very fast AND fairly fault tolerant. You "pay" the equivalent of one drive ie. - in this case - 100 GB for the security of your data, but you end up with a 300 GB drive array and the ability to swap/hotswap a drive and rebuild the array should one of the drives fail. Also, by using UDMA/100 5400 instead of 7200 drives you get a slightly slover performance, but you gain by having much lower temperatures and much lower noise levels. Such a Raid 5 system would cost around 1300 US (depending where you buy) for 300 GB, but your data is much more secure than the simpler and cheaper Raid 0. Lastly, these stand alone Raid cards - unlike raid solutions on motherbords - have their own processors on board which takes over all the hard work, freeing up your system processor. GreetingsPreben - Original Message - From: "James Grove" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Sunday, November 11, 2001 9:46 AM Subject: RE: filmscanners: Best solution for HD and images > I have just ordered a 60 Gig Maxtor ATA 100 drive (ATA 133 is also > available) I have done this because it is far cheaper than buying > another 36 gig drive to go on my U160 SCSI channel. I can get the Maxtor > drives for around 60 UK pounds, which means I could buy 4 of these IDE > drives for the same price as a Quantum U160 36gig drive! > > One thing to remember about Ide if you decide to give the drive a > beasting is to cool it with a slim cooler. > > -- > James Grove > [EMAIL PROTECTED] > www.jamesgrove.co.uk > www.mountain-photos.co.uk > ICQ 99737573 > > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]] On Behalf Of Ezio c/o TIN > Sent: 10 November 2001 21:18 > To: [EMAIL PROTECTED] > Subject: Re: filmscanners: Best solution for HD and images > > > I would recommend to buy a U-160 SCSI ... from e-bay ... I have just > done this to integrate the other 3 U-160 I have and I have bought for > 102US $ a 18GB IBM 1 rpm brand new under warranty. A 36GB 1rpm > also IBM U-160 is rated for 170 US $ ... > > Sincerely. > > Ezio > > www.lucenti.com e-photography site > > > - Original Message - > From: "Andrea de Polo" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Saturday, November 10, 2001 4:53 PM > Subject: filmscanners: Best solution for HD and images > > > > Hello, > > > > I have a CreoScitex scanner with attached a, Apple G4 Silver 733 with > > OS > 9.2.1 and 1GB of ram; I noticed that the internal HD is a slow 5400rpm > UltraAta HD; question: since I work only with Photoshop and my images > are about 60mb in size and I just have to open and save them during the > day (we process about 200 images/day), I was wondering what is the best > and effective way to speed up my work: buy a scsi external HD 10.000rpm > (total cost about 650 UK pounds), OR buy an internal UltraAta 7200 rpm > (total cost about 250 UK pounds) ??? > > > > Again, we just have to open, retouch and than save our 40mb images, > > but > currently I am noticing that is taking a bit to access the HD. > > > > Thanks to give me your best solution for time/money issue. Andrea > > -- > > > > Fratelli Alinari Photo Archives and Museum > > http://www.alinari.com > > The world's oldest picture library > > tel: +39-055-2395201 > > gsm: +39-347-4883223 > > fax: +39-055-2382857 > > > > > > >
RE: filmscanners: Best solution for HD and images
I have just ordered a 60 Gig Maxtor ATA 100 drive (ATA 133 is also available) I have done this because it is far cheaper than buying another 36 gig drive to go on my U160 SCSI channel. I can get the Maxtor drives for around 60 UK pounds, which means I could buy 4 of these IDE drives for the same price as a Quantum U160 36gig drive! One thing to remember about Ide if you decide to give the drive a beasting is to cool it with a slim cooler. -- James Grove [EMAIL PROTECTED] www.jamesgrove.co.uk www.mountain-photos.co.uk ICQ 99737573 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Ezio c/o TIN Sent: 10 November 2001 21:18 To: [EMAIL PROTECTED] Subject: Re: filmscanners: Best solution for HD and images I would recommend to buy a U-160 SCSI ... from e-bay ... I have just done this to integrate the other 3 U-160 I have and I have bought for 102US $ a 18GB IBM 1 rpm brand new under warranty. A 36GB 1rpm also IBM U-160 is rated for 170 US $ ... Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "Andrea de Polo" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, November 10, 2001 4:53 PM Subject: filmscanners: Best solution for HD and images > Hello, > > I have a CreoScitex scanner with attached a, Apple G4 Silver 733 with > OS 9.2.1 and 1GB of ram; I noticed that the internal HD is a slow 5400rpm UltraAta HD; question: since I work only with Photoshop and my images are about 60mb in size and I just have to open and save them during the day (we process about 200 images/day), I was wondering what is the best and effective way to speed up my work: buy a scsi external HD 10.000rpm (total cost about 650 UK pounds), OR buy an internal UltraAta 7200 rpm (total cost about 250 UK pounds) ??? > > Again, we just have to open, retouch and than save our 40mb images, > but currently I am noticing that is taking a bit to access the HD. > > Thanks to give me your best solution for time/money issue. Andrea > -- > > Fratelli Alinari Photo Archives and Museum > http://www.alinari.com > The world's oldest picture library > tel: +39-055-2395201 > gsm: +39-347-4883223 > fax: +39-055-2382857 > >
Re: filmscanners: Best solution for HD and images
I would recommend to buy a U-160 SCSI ... from e-bay ... I have just done this to integrate the other 3 U-160 I have and I have bought for 102US $ a 18GB IBM 1 rpm brand new under warranty. A 36GB 1rpm also IBM U-160 is rated for 170 US $ ... Sincerely. Ezio www.lucenti.com e-photography site - Original Message - From: "Andrea de Polo" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, November 10, 2001 4:53 PM Subject: filmscanners: Best solution for HD and images > Hello, > > I have a CreoScitex scanner with attached a, Apple G4 Silver 733 with OS 9.2.1 and 1GB of ram; I noticed that the internal HD is a slow 5400rpm UltraAta HD; question: since I work only with Photoshop and my images are about 60mb in size and I just have to open and save them during the day (we process about 200 images/day), I was wondering what is the best and effective way to speed up my work: buy a scsi external HD 10.000rpm (total cost about 650 UK pounds), OR buy an internal UltraAta 7200 rpm (total cost about 250 UK pounds) ??? > > Again, we just have to open, retouch and than save our 40mb images, but currently I am noticing that is taking a bit to access the HD. > > Thanks to give me your best solution for time/money issue. > Andrea > -- > > Fratelli Alinari Photo Archives and Museum > http://www.alinari.com > The world's oldest picture library > tel: +39-055-2395201 > gsm: +39-347-4883223 > fax: +39-055-2382857 > >
Re: filmscanners: Best solution for HD and images
Hi Andrea-- First allocate around 300MB to Photoshop and see if this significantly reduces the amount of disk accesses. The logic here is that Photoshop needs working space (for each image you have open?) of about 3 times the image size, plus it needs space for its code to run, plus any scanner plug-in will need memory for its working space too. I'm not up to date on the relative speeds of disk technologies, so I can't give you a reliable recommendation, but you might look into external RAID arrays. These can be placed in a mode were the data is split across multiple disk drives such that you read and write to them in parallel. This multiplies the transfer rate by roughly the number of hard disks: so for example a 4-disk array would give you roughly 4 times the speed. I'm under the impression that such RAID arrays are popular with digital video studios because they transfer massive amounts of data quickly. --Bill At 4:53 PM +0100 10-11-01, Andrea de Polo wrote: >Hello, > >I have a CreoScitex scanner with attached a, Apple G4 Silver 733 >with OS 9.2.1 and 1GB of ram; I noticed that the internal HD is a >slow 5400rpm UltraAta HD; question: since I work only with Photoshop >and my images are about 60mb in size and I just have to open and >save them during the day (we process about 200 images/day), I was >wondering what is the best and effective way to speed up my work: >buy a scsi external HD 10.000rpm (total cost about 650 UK pounds), >OR buy an internal UltraAta 7200 rpm (total cost about 250 UK >pounds) ??? > >Again, we just have to open, retouch and than save our 40mb images, >but currently I am noticing that is taking a bit to access the HD. -- == Bill Fernandez * User Interface Architect * Bill Fernandez Design (505) 346-3080 * [EMAIL PROTECTED] * http://billfernandez.com ==
