Re: HP 7970E - interest to split?

[Chuck Guzis via cctalk]

Hi Anders,

I found the reason for my SD card problems--a missing semicolon.   There
was supposed to be a stall until SDIO transfer complete; instead of a
stall, the next statement was being executed.

Argh.  It's those little things that really trip you up.

At any rate, I've even got read-reverse working, so I can read a block,
parity check it and retry automatically if there's an error.

Not too shabby for a $10 MCU board.

--Chuck

Re: HP 7970E - interest to split?

[Chuck Guzis via cctalk]

On 09/29/2017 03:01 PM, Al Kossow via cctalk wrote:
> 
> 
> On 9/29/17 11:35 AM, Chuck Guzis via cctalk wrote:
> 
>> Does the little Kennedy drive have a vacuum takeup reel?
> 
> No, they are tension arm, very similar design to the 7970
> 
> I wanted to compare the mechanical design of the 9000 to the 7970
> but don't know if I have the time/interest any more.

No, that's not what I meant.  Some drives put a slight vacuum on the
takeup reel hub, so that the tape "sticks" to the hub--no finger hole
needed.

I've got all the programming done for the drive, including auto retries
if there's a parity error.   Reading is pretty good for 50+ year old
tapes (the ones I'm reading appear to be from the 1976 Viking missions).
 They look like session transcripts--you can see the command and the
response.

Still a few too many read errors for my taste, so this weekend is going
to be a session with a 'scope and alignment tape.   I think I've got a
way to adjust skew--just hook a logic analyzer probe to each channel and
set the LA to trigger on state changes.   The HP box I'm using is good
to about 25 nsec.

--Chuck

Re: formatting MFM drives on a IBM PC

[js--- via cctalk]

On 9/29/2017 9:54 PM, Chuck Guzis via cctalk wrote:

On 09/29/2017 07:04 PM, Warner Losh via cctalk wrote:


I think there are two barriers to that. No sata is a cards. And BIOS of
that era still required you to tell it the chs for the drive...

So, let's change the acronym to SSATA - "Serial Sort-of AT Attachment"

--Chuck


SPATA - "Serial Post AT Attachment"

-- J.

Re: HP 7970E - interest to split?

[Jon Elson via cctalk]

On 09/29/2017 01:35 PM, Chuck Guzis via cctalk wrote:

On 09/29/2017 09:00 AM, Al Kossow via cctalk wrote:


On 9/29/17 8:48 AM, Jon Elson via cctalk wrote:


I did a few of these on a lathe years ago.  It was a couple minutes job per 
reel.

you are also going to have to cut holes near the hub so that you can get a tape 
started
on the takeup reel.

Does the little Kennedy drive have a vacuum takeup reel?   The 7970
certainly doesn't--no fans in that box at all.  I've wondered about
applying a low-tack glue dot to the hub of the takeup reel to speed loading.



Yes, some drives had some kind of elastomer ring in the 
takeup reel that would grab most tapes and wrap them quite 
nicely with no finger hole.


Jon

Re: formatting MFM drives on a IBM PC

[Chuck Guzis via cctalk]

On 09/29/2017 07:04 PM, Warner Losh via cctalk wrote:

> I think there are two barriers to that. No sata is a cards. And BIOS of
> that era still required you to tell it the chs for the drive...

So, let's change the acronym to SSATA - "Serial Sort-of AT Attachment"

--Chuck

Re: formatting MFM drives on a IBM PC

[Warner Losh via cctalk]

On Sep 29, 2017 6:49 AM, "Peter Corlett via cctalk" 
wrote:

On Thu, Sep 28, 2017 at 05:36:40PM -0700, Chuck Guzis via cctalk wrote:
[...]
> What I find perplexing is the acronym "SATA" for "Serial ATA". The name
would
> imply that a drive can be connected to a 5170, but I'm not aware of any
SATA
> adapters for the 5170 PC/AT.

SATA has a different electrical interface, but otherwise speaks the same
protocol as the older (P)ATA protocol. Converters are cheap and readily
available.

So yes, you could stick a SATA disk in your old 5170, assuming that the BIOS
doesn't immediately faint when presented with a very large disk.


I think there are two barriers to that. No sata is a cards. And BIOS of
that era still required you to tell it the chs for the drive...

Warned

Re: formatting MFM drives on a IBM PC

[Mike Stein via cctalk]

- Original Message - 
From: "Ali via cctalk" 
To: "'General Discussion: On-Topic and Off-Topic Posts'" 
Sent: Friday, September 29, 2017 5:31 PM
Subject: RE: formatting MFM drives on a IBM PC


> And, that won't work, either.  The BIOS in older machines will not work
> right at ALL with a high capacity drive.
> In some cases you will get a usable volume with vastly reduced
> capacity, but in most cases it will just not recognize the drive at
> all.  I'm not talking about original AT's here, but mid-90's 386 and
> 486 systems.
> I can only imagine a real AT would be even less likely to handle a
> drive over about 40 MB.


This is really not a big issue. All you need is a BIOS on the IDE controller 
card. It was very common back in the day that many add-in drive controllers had 
their own BIOS so you are not even breaking new ground here. In fact someone 
far more talented then I could probably design a 16bit controller card w/ its 
own BIOS that also has the PATA -> SATA adapter interface built in all on one 
card and your 5170 can be rocking an SSD drive! Heck the XT-IDE project 
practically does this already with a CF or SD card plugged into the card...
--
... And of course the drive manufacturers supplied drive overlay programs that 
bypassed the BIOS settings to accommodate larger or undefined drives.

m

Re: HP 7970E - interest to split?

[Al Kossow via cctalk]

On 9/29/17 11:35 AM, Chuck Guzis via cctalk wrote:

> Does the little Kennedy drive have a vacuum takeup reel?

No, they are tension arm, very similar design to the 7970

I wanted to compare the mechanical design of the 9000 to the 7970
but don't know if I have the time/interest any more.

RE: formatting MFM drives on a IBM PC

[Ali via cctalk]

> And, that won't work, either.  The BIOS in older machines will not work
> right at ALL with a high capacity drive.
> In some cases you will get a usable volume with vastly reduced
> capacity, but in most cases it will just not recognize the drive at
> all.  I'm not talking about original AT's here, but mid-90's 386 and
> 486 systems.
> I can only imagine a real AT would be even less likely to handle a
> drive over about 40 MB.


This is really not a big issue. All you need is a BIOS on the IDE controller 
card. It was very common back in the day that many add-in drive controllers had 
their own BIOS so you are not even breaking new ground here. In fact someone 
far more talented then I could probably design a 16bit controller card w/ its 
own BIOS that also has the PATA -> SATA adapter interface built in all on one 
card and your 5170 can be rocking an SSD drive! Heck the XT-IDE project 
practically does this already with a CF or SD card plugged into the card...

Re: HP 9845 complete system on auction in Sweden

[Ed via cctalk]

yes if   the tree sap stuff  if  can get fungus in  it.  had that happen to 
microscope lenses in the lab
Ed#
 
 
In a message dated 9/29/2017 2:11:26 P.M. US Mountain Standard Time,  
cctalk@classiccmp.org writes:

On Fri,  29 Sep 2017, Ed via cctalk wrote:
> what  was the orig. bonding  material between   face glass  and  tube? 
just
>  curious

fungus?

Re: HP 9845 complete system on auction in Sweden

[Fred Cisin via cctalk]

On Fri, 29 Sep 2017, Ed via cctalk wrote:

what  was the orig. bonding material between   face glass  and  tube? just
curious


fungus?

Re: formatting MFM drives on a IBM PC

[Fred Cisin via cctalk]

"Low level format" is pretty much a relic of the old non-servo MFM
drives.   I recall that early Maxtor IDE drives implemented a LLF


On Fri, 29 Sep 2017, Christian Corti via cctalk wrote:
Lowlevel formatting has to be done for *all* ST-506 interface drives (e.g. 
"MFM" and "RLL" drives). It is the disk controller that needs to write its 
sector and track layout to the drive (ID marks, data marks, GAPs, CRC, ECC 
and so on). This is also true for SMD drives, for example. So it didn't 
make much sense in selling preformatted drives until when disk drives
exposed only the disk blocks to the host. Whether a drives uses servo 
information or not is irrelevant. I don't consider writing servo 
information as lowlevel formatting.


You'd think so.
But, the exact same thing applied to floppy disks.
Formatting has to be done for *all* floppy disks.  It is the disk 
controller/FDC that needs to write its sector and track layout to the 
drive (ID marks, data marks, GAPs, CRC,  and so on.


Obviously, they would not be pre-formatted, since the format could be done 
in multiple ways.
But, SOME manufacturers did not provide the user with a way to do that 
format (DEC, etc.)


AND, once a SIGNIFICANT portion of the market had standardized on one 
particular format, the floppy manufacturers started to sell them 
pre-formatted.  If you need a different format, then you can manually 
reformat them yourself.   (You can erase a PC formatted disk and RE-format 
it for a few thousand other formats)


Similarly, when the majority of the market wanted IBM/WD1003 "AT" 
drives, preformatting became feasible.  "You can RE-format if it's not 
what you wnat."

Re: formatting MFM drives on a IBM PC

[Fred Cisin via cctalk]

On 09/29/2017 11:20 AM, Jon Elson via cctalk wrote:

I can only imagine a real AT would be even less likely to handle a drive
over about 40 MB.


40MB would not be much of a problem.
DOS, through 3.30 had a limit of 32MB per partition, but you could upgrade 
to newer DOS, or break it up into multiple partitions.  An ST250 (40MB) 
could be two 20MB, or a 32MB and an 8MB, depending on your type of need. 
An  ST4096 (80MB) could be 3 partitions.


On Fri, 29 Sep 2017, Jules Richardson via cctalk wrote:
I think the limit was normally 512MB in the old c/h/s addressing days, 
wasn't it? For a connected drive, the BIOS set aside 4 bits for the number 
of heads per cylinder, 6 bits for the sectors per track, and 10 bits for 
the number of cylinders - i.e. maximums of 16, 64 and 1024. At 512 bytes 
per sector, that came out as 512MB.


In addition, there used to be a 2GB limit imposed by DOS.  It should have 
been a 4GB limit, but they used a SIGNED long int, instead of unsigned, so 
the size of the drive could be from -2147483648 to 2147483647 bytes.


Similarly file size was from -2147483648 to 2147483647.  If you stepped 
on a directory entry, you could change a file size to be NEGATIVE!
OK, change a file on a floppy to have a file size of 8000 h.  DOS now 
reports it as -2147483648.  Or  h (-1).  Copy a negative sized 
file to the drive and that should increase the free space, right?

Didn't work.


Older BIOS firmware provided no means for the user to define the geometry 
of a connected drive - just a list of predefined types, and those often 
maxed out at far less than any 512MB limit. There were various software 
solutions to get around it, though.


Of course operating systems had various limits on the maximum size of a 
partition on top of that - e.g. I think it was 32MB in earlier versions of 
MS-DOS.


What are the current drive size limits?

Re: HP 9845 complete system on auction in Sweden

[Ed via cctalk]

Paul so the case it self is what held the class in place  then?
Ed#
 
 
In a message dated 9/29/2017 11:00:27 A.M. US Mountain Standard Time,  
cctalk@classiccmp.org writes:

On my  9835A it was Canadian Balsam a common optical bonding material.   
I  bonded the shield on my to the front of the case using epoxy.  I had  
tried tape but it slowly settled to the bottom of the case, I guess my  
tape was not thick enough.  In a very old TV I once had there was  just a 
sheet of plate  glass set into the front of the cabinet in  front of a 
tube that did not have any implosion  protection.

Paul.
>   

Re: HP 7970E - interest to split?

[Chuck Guzis via cctalk]

On 09/29/2017 09:00 AM, Al Kossow via cctalk wrote:
> 
> 
> On 9/29/17 8:48 AM, Jon Elson via cctalk wrote:
> 
>> I did a few of these on a lathe years ago.  It was a couple minutes job per 
>> reel.
> 
> you are also going to have to cut holes near the hub so that you can get a 
> tape started
> on the takeup reel.

Does the little Kennedy drive have a vacuum takeup reel?   The 7970
certainly doesn't--no fans in that box at all.  I've wondered about
applying a low-tack glue dot to the hub of the takeup reel to speed loading.


--Chuck

Re: formatting MFM drives on a IBM PC

[Chuck Guzis via cctalk]

For what it's worth, I found long ago that the IDE interface was far
closer to the PC-based ESDI controller command set than the WD MFM drive
one.  ESDI even responds to commands such as IDENTIFY, where that
command doesn't exist in the WD1003-type controller vocabulary.  ESDI
also supports larger (>512MB) drives without breaking a sweat.

--Chuck

Re: HP 9845 complete system on auction in Sweden

[Paul Berger via cctalk]

On 2017-09-29 2:02 PM, Ed via cctalk wrote:

Cory - good  suggestion about the double sided  tape.
  
what  was the orig. bonding material between   face glass  and  tube? just

curious
Ed#
On my 9835A it was Canadian Balsam a common optical bonding material.   
I bonded the shield on my to the front of the case using epoxy.  I had 
tried tape but it slowly settled to the bottom of the case, I guess my 
tape was not thick enough.  In a very old TV I once had there was just a 
sheet of plate  glass set into the front of the cabinet in front of a 
tube that did not have any implosion protection.


Paul.
  
  
In a message dated 9/26/2017 5:29:30 A.M. US Mountain Standard Time,

coryheisterk...@gmail.com writes:

  
  


It's the understood chemical decomposition of the  adhesive that holds the
screen shield to the CRT.  It's pretty much  inevitable, from what I
understand.  The solution is to separate the  shield from the CRT, clean the 
face
of the CRT and reattach the  shield.  Some people don't reattach it, and some
people think they are  risking serious injury - no opinion. Will the newer
adhesives hold up  better?  We hope so.  -- Ian

--

Ian S. King,  MSIS, MSCS, Ph.D. Candidate
The Information School








A common trick amongst TV collectors with the  large 23" round CRTs is to
carefully remove the tube and place it face down in  a kiddy pool of lukewarm
water. Let it sit an hour or two in the sun and the  faceplate will slide
right off.


To re-adhere the glass after cleaning, one technique is  to use double
sided foam tape on the face around the perimeter; similar  thickness to the
original PVA and holds well, especially if under slight  compression once the
tube is reinstalled.  -C

Re: formatting MFM drives on a IBM PC

[Guy Sotomayor Jr via cctalk]

> On Sep 29, 2017, at 10:35 AM, Jules Richardson via cctalk 
>  wrote:
> 
> On 09/29/2017 11:20 AM, Jon Elson via cctalk wrote:
>> I can only imagine a real AT would be even less likely to handle a drive
>> over about 40 MB.
> 
> I think the limit was normally 512MB in the old c/h/s addressing days, wasn't 
> it? For a connected drive, the BIOS set aside 4 bits for the number of heads 
> per cylinder, 6 bits for the sectors per track, and 10 bits for the number of 
> cylinders - i.e. maximums of 16, 64 and 1024. At 512 bytes per sector, that 
> came out as 512MB.

Yes, and I can say that I’m the one responsible for that restriction.  :-o  At 
the time we needed to support our LBA controllers and we figured that the 
restriction was OK because we’d have a BIOS replacement long before disk drives 
got that big.  We were wrong on both counts: drives got bigger a whole lot 
faster than we expected and that a BIOS replacement took a whole lot longer to 
make it into systems.  *sigh*

> 
> Older BIOS firmware provided no means for the user to define the geometry of 
> a connected drive - just a list of predefined types, and those often maxed 
> out at far less than any 512MB limit. There were various software solutions 
> to get around it, though.

The above (512MB max disk size) came about with the PS/2.  Prior to that BIOS 
just had predefined types.

TTFN - Guy

Re: formatting MFM drives on a IBM PC

[Jules Richardson via cctalk]

On 09/29/2017 11:20 AM, Jon Elson via cctalk wrote:

I can only imagine a real AT would be even less likely to handle a drive
over about 40 MB.


I think the limit was normally 512MB in the old c/h/s addressing days, 
wasn't it? For a connected drive, the BIOS set aside 4 bits for the number 
of heads per cylinder, 6 bits for the sectors per track, and 10 bits for 
the number of cylinders - i.e. maximums of 16, 64 and 1024. At 512 bytes 
per sector, that came out as 512MB.


Older BIOS firmware provided no means for the user to define the geometry 
of a connected drive - just a list of predefined types, and those often 
maxed out at far less than any 512MB limit. There were various software 
solutions to get around it, though.


Of course operating systems had various limits on the maximum size of a 
partition on top of that - e.g. I think it was 32MB in earlier versions of 
MS-DOS.


cheers

Jules

Re: HP 9845 complete system on auction in Sweden

[Ed via cctalk]

Cory - good  suggestion about the double sided  tape.
 
what  was the orig. bonding material between   face glass  and  tube? just 
curious
Ed#
 
 
In a message dated 9/26/2017 5:29:30 A.M. US Mountain Standard Time,  
coryheisterk...@gmail.com writes:

 
 

It's the understood chemical decomposition of the  adhesive that holds the 
screen shield to the CRT.  It's pretty much  inevitable, from what I 
understand.  The solution is to separate the  shield from the CRT, clean the 
face 
of the CRT and reattach the  shield.  Some people don't reattach it, and some 
people think they are  risking serious injury - no opinion. Will the newer 
adhesives hold up  better?  We hope so.  -- Ian 

--

Ian S. King,  MSIS, MSCS, Ph.D. Candidate
The Information School








A common trick amongst TV collectors with the  large 23" round CRTs is to 
carefully remove the tube and place it face down in  a kiddy pool of lukewarm 
water. Let it sit an hour or two in the sun and the  faceplate will slide 
right off. 


To re-adhere the glass after cleaning, one technique is  to use double 
sided foam tape on the face around the perimeter; similar  thickness to the 
original PVA and holds well, especially if under slight  compression once the 
tube is reinstalled.  -C

Re: HP 7970E - interest to split?

[Paul Koning via cctalk]

> On Sep 29, 2017, at 12:33 PM, Jon Elson via cctalk  
> wrote:
> 
> On 09/29/2017 10:56 AM, Henk Gooijen via cctalk wrote:
>> 
>> 
>> 
>> On a related note my plan is to make a USB-based, Pertec-compatible
>> controller for it. Not sure how SimH connects with peripherals so I'm
>> /very/ eager to talk with someone familiar with its workings. I'll also
>> release all the board files and firmware as open-source. Timeline as always
>> is completely unknown, though I do have a now-vested interest in making it
>> work.

It looks like it only handles tape container files (.TAP files) right now.  But 
the machinery basically has a tape emulation module (sim_tape.c) which has a 
number of functions roughly corresponding to what a tape drive does (read 
forward, write tape mark, rewind, etc.).  It doesn't look like a terribly hard 
task to support a real tape drive as another "container file format".  One 
question I can think of is how OS-dependent raw SCSI access is.

The approach would be somewhat similar to the disk support in SIMH, which does 
already have "RAW" as one of the formats, meaning direct access to a real disk.

> MANY, MANY years ago I got a surplus Pertec key to tape system that had a 7" 
> 9-track 800 BPI NRZI drive connected to hardwired logic. You could key in 
> data, verify data by re-keying it, and read back data to a panel of light 
> bulbs.  It had core memory for the data buffer.
> 
> I found the right place to slice the sections apart and have what was pretty 
> close to the unformatted Pertec interface.
> I then wrote a mostly software-driven interface to read and write tape blocks 
> on my CP/M Z-80 system.  I created tapes and took them in to work to map them 
> and got it to write ASCII text files in VAX ANSI-D format.  It really was not 
> that complicated.  This was a read/write drive with only a single data gap.  
> So, to write and check a record, you had to write it, back up and read it.  I 
> used it for making backups.
> 
> I think you could use a Beagle Bone and the PRU microcontrollers in it to do 
> a Pertec unformatted interface.

I wonder if a BBB is fast enough that you can just drive the Pertec interface 
directly from the GPIO pins.  At 1 GHz lots of things become possible in 
software...

I noticed there is a BB "Cape" (I/O board) with a medium size FPGA on it.  
Haven't found a use for that yet, but it looks pretty powerful for those case 
where software isn't quite fast enough.

paul

Re: HP 7970E - interest to split?

[Jon Elson via cctalk]

On 09/29/2017 10:56 AM, Henk Gooijen via cctalk wrote:




On a related note my plan is to make a USB-based, Pertec-compatible
controller for it. Not sure how SimH connects with peripherals so I'm
/very/ eager to talk with someone familiar with its workings. I'll also
release all the board files and firmware as open-source. Timeline as always
is completely unknown, though I do have a now-vested interest in making it
work.


MANY, MANY years ago I got a surplus Pertec key to tape 
system that had a 7" 9-track 800 BPI NRZI drive connected to 
hardwired logic. You could key in data, verify data by 
re-keying it, and read back data to a panel of light bulbs.  
It had core memory for the data buffer.


I found the right place to slice the sections apart and have 
what was pretty close to the unformatted Pertec interface.
I then wrote a mostly software-driven interface to read and 
write tape blocks on my CP/M Z-80 system.  I created tapes 
and took them in to work to map them and got it to write 
ASCII text files in VAX ANSI-D format.  It really was not 
that complicated.  This was a read/write drive with only a 
single data gap.  So, to write and check a record, you had 
to write it, back up and read it.  I used it for making backups.


I think you could use a Beagle Bone and the PRU 
microcontrollers in it to do a Pertec unformatted interface.
The only issue is that the PRUs have a fast local memory of 
very limited size.  There is a way to open a memory
map to the ARM system memory from the PRU, although the 
shared memory is 12 K bytes, which might be enough to handle 
many uses.


I did an FPGA-based adapter to Pertec formatted interface 
using the parallel port.  (Slow, but I already had all the 
FPGA and computer side infrastructure to make that work.)  I 
have some CDC Keystone (92185) drives.


Jon

Re: formatting MFM drives on a IBM PC

[Jon Elson via cctalk]

On 09/29/2017 10:46 AM, Mike Stein via cctalk wrote:

- Original Message -
From: "Chuck Guzis via cctalk" 
To: "Paul Koning" ; "General Discussion: On-Topic and Off-Topic 
Posts" 
Sent: Friday, September 29, 2017 11:29 AM
Subject: Re: formatting MFM drives on a IBM PC



On 09/29/2017 06:07 AM, Paul Koning wrote:


There are chips that convert between serial and parallel ATA; one of
those could perhaps be used.  I'm more used to applying them for
attaching a serial ATA controller to a parallel ATA drive, but
possibly they might work in the other direction as well.  Not clear
if they are still common products, given that parallel ATA is pretty
old, but they may still be available.

Oh, I've got a pile of such converters--workability is variable.

What I was saying is that I've never seen an ISA interface card to a
SATA drive.  Have you?

--Chuck

--
Well, I haven't seen an IDE interface card to a PATA drive either for quite a 
while since they started integrating everything into the motherboard but OK, I'll 
grant you that you'd probably need a PATA>SATA adapter if you wanted to Attach 
a SATA drive to a genooine IBM AT.


And, that won't work, either.  The BIOS in older machines 
will not work right at ALL with a high capacity drive.
In some cases you will get a usable volume with vastly 
reduced capacity, but in most cases it will just not
recognize the drive at all.  I'm not talking about original 
AT's here, but mid-90's 386 and 486 systems.
I can only imagine a real AT would be even less likely to 
handle a drive over about 40 MB.


Jon

Re: formatting MFM drives on a IBM PC

[Paul Koning via cctalk]

> On Sep 29, 2017, at 11:29 AM, Chuck Guzis  wrote:
> 
> On 09/29/2017 06:07 AM, Paul Koning wrote:
> 
>> There are chips that convert between serial and parallel ATA; one of
>> those could perhaps be used.  I'm more used to applying them for
>> attaching a serial ATA controller to a parallel ATA drive, but
>> possibly they might work in the other direction as well.  Not clear
>> if they are still common products, given that parallel ATA is pretty
>> old, but they may still be available.
> 
> Oh, I've got a pile of such converters--workability is variable.
> 
> What I was saying is that I've never seen an ISA interface card to a
> SATA drive.  Have you?

No, but my exposure is pretty limited.  I ran into these devices in the first 
generation of SAN product I worked on around 2002.  We adopted SATA because it 
allows connecting lots of drives (14, in our case) over a backplane, without 
running out of space.  But at the time, only "PATA" drives were available, so 
we used converters.  Also, those converters supplied dual channel operation 
(one from each of a pair of redundant controllers).

Storage protocols are asymmetric, so it isn't necessarily the case that a P-S 
ATA converter that works for SATA adapter to PATA drive will also work for the 
other case.  But it might well, you'd have to look at the specs (and then 
verify that they are true).  It's not a case I have had to worry about so I 
don't have any additional information.

paul

Re: HP 7970E - interest to split?

[Al Kossow via cctalk]

On 9/29/17 8:48 AM, Jon Elson via cctalk wrote:

> I did a few of these on a lathe years ago.  It was a couple minutes job per 
> reel.

you are also going to have to cut holes near the hub so that you can get a tape 
started
on the takeup reel.

RE: HP 7970E - interest to split?

[Henk Gooijen via cctalk]

Van: Anders Nelson via cctalk
Verzonden: vrijdag 29 september 2017 05:57
Aan: General Discussion: On-Topic and Off-Topic 
Posts
Onderwerp: Re: HP 7970E - interest to split?

Update: I bought the Kennedy 9800 as it pushed all my buttons at once.

Now I'm looking for 8" mag tapes/reels that will fit! Anyone know where I
can find these, maybe 3pcs? I could laser-cut some frosted acrylic or
machine some frosted polycarbonate I suppose but I'd rather just buy it,
plus that would include a dust cover.

On a related note my plan is to make a USB-based, Pertec-compatible
controller for it. Not sure how SimH connects with peripherals so I'm
/very/ eager to talk with someone familiar with its workings. I'll also
release all the board files and firmware as open-source. Timeline as always
is completely unknown, though I do have a now-vested interest in making it
work.

Be well!

Looking forward to see that controller “materialize”.

I could -give- you 3 8” mag tapes with (manual) sealing ring, but the
catch is, I am in the Netherlands.  Don’t know what shipping cost
would be, but my guess is between $25 - $35.
If you cannot get the 8” tapes over there, this might be an option.

I saw the 9800 auction briefly. Nice looking unit!  From memory, the
tape reel has the same size as fitting on the TS03?  I will measure the
reel dimensions tomorrow to make sure that they are 8”. I have open
reel tapes in 2 sizes, so probably it is 10.5” and 8”, although ISTR that
the size was 7”.

Henk

Re: Reviving ancient MFM drives (was Re: formatting MFM drives on a IBM PC)

[Geoffrey Oltmans via cctalk]

On Fri, Sep 29, 2017 at 3:05 AM, Christian Corti via cctalk <
cctalk@classiccmp.org> wrote:

> On Thu, 28 Sep 2017, Geoffrey Oltmans wrote:
>
>> Speaking of I've got a couple of old MFM drives (10 and 20 MB of a
>> variety whose name and model #'s escape me, I wanna say Tandon, but not
>> sure). They seem to work fine when I initially format and partition, but
>> as
>> they run for a while, they get more and more unreliable. It seems to be a
>> function of how long they've been running for rather than a predictable
>> pattern of bad tracks sectors? Are there any good sources of
>> troubleshooting info at the controller level for these old drives?
>>
>
> Well, that's normal. The usual procedure is to let the drive warm up for
> 10-20 minutes before formatting. And it is also normal for some models that
> they must be reformatted after, say, a couple of months or years, depending
> on make and manufacturer. The Rhodime 50MB drive in my IBM 8550 is such a
> beast. My procedure is to run Norton CALIBRAT to reformat the drive
> losslessly.
>
>
> Good idea. I'll give that a shot.

Re: HP 7970E - interest to split?

[Jon Elson via cctalk]

On 09/28/2017 11:44 PM, Anders Nelson via cctalk wrote:

Hi Chuck,

Yeah I could try that but unless I can separate the reel halves from the
hub I'd have to make a jig of sorts to absorb the laser beam on the bottom
side of the cut. Can the sides be separated? And is it possible to cut down
a dust cover?


I did a few of these on a lathe years ago.  It was a couple 
minutes job per reel.
Dust cover?  You mean the ring that goes around the reel?  
Yes, these can be cut down.
Generally, they have black plastic parts that snap into a 
hole on the end of the ring.
You take out one of the end pieces, cut the ring and then 
cut the hole in the ring that the
end piece fits into with an X-acto knife.  You may have to 
narrow the rims of the reel so the
ring fits right.  That's why the lathe is better than the 
laser cutter.  Generally, the flanges are
glued together to the hub, and you will not be able to 
disassemble them.


Jon

RE: HP 7970E - interest to split?

[Henk Gooijen via cctalk]

Van: Steve Malikoff via cctalk
Verzonden: vrijdag 29 september 2017 09:26
Aan: General Discussion: On-Topic and Off-Topic 
Posts
Onderwerp: Re: HP 7970E - interest to split?

On my Kennedy 9000s the rubber O-rings have expanded on all the spindles and a
reel has a lot of trouble being pushed on and removed. I plan to replace them 
with
neoprene O-rings of the original size. These are readily available and cheap 
from
bearing supplies stores, I'll get a range of close sizes and find the right one.

Steve.

I have read that putting the rubber rings in warm water
will make them shrink to their orginal sze, but keep their
Specifications. Worth a try …

Re: formatting MFM drives on a IBM PC

[Mike Stein via cctalk]

- Original Message - 
From: "Chuck Guzis via cctalk" 
To: "Paul Koning" ; "General Discussion: On-Topic and 
Off-Topic Posts" 
Sent: Friday, September 29, 2017 11:29 AM
Subject: Re: formatting MFM drives on a IBM PC


> On 09/29/2017 06:07 AM, Paul Koning wrote:
> 
>> There are chips that convert between serial and parallel ATA; one of
>> those could perhaps be used.  I'm more used to applying them for
>> attaching a serial ATA controller to a parallel ATA drive, but
>> possibly they might work in the other direction as well.  Not clear
>> if they are still common products, given that parallel ATA is pretty
>> old, but they may still be available.
> 
> Oh, I've got a pile of such converters--workability is variable.
> 
> What I was saying is that I've never seen an ISA interface card to a
> SATA drive.  Have you?
> 
> --Chuck
--
Well, I haven't seen an IDE interface card to a PATA drive either for quite a 
while since they started integrating everything into the motherboard but OK, 
I'll grant you that you'd probably need a PATA>SATA adapter if you wanted to 
Attach a SATA drive to a genooine IBM AT.

Sigh...
;-)

m

Re: formatting MFM drives on a IBM PC

[Chuck Guzis via cctalk]

On 09/29/2017 01:11 AM, Christian Corti via cctalk wrote:

> I don't consider writing servo information as lowlevel formatting.

I should have been more precise.  What I meant was "embedded servo".
Most, if not all,  modern drives use this technique rather than dedicate
a separate surface to servo.   There's no low-level format with this.
It's been around since at least the 1970s, but was slow to be adopted by
the PC drive manufacturers.  An interesting aside is that the Drivetec
floppy diskettes used embedded servo--which was why you had to purchase
them preformatted.

I recall visiting a friend at Tandon's "R" operation during the 80s.
The servo writer for the lab was an affair mounted on a granite block
and employed a laser for determining position.

At any rate, I hope this clears up what I meant.

--Chuck

Re: formatting MFM drives on a IBM PC

[Geoffrey Oltmans via cctalk]

On Thu, Sep 28, 2017 at 7:36 PM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

>
> What I find perplexing is the acronym "SATA" for "Serial ATA".  The name
> would imply that a drive can be connected to a 5170, but I'm not aware
> of any SATA adapters for the 5170 PC/AT.
>

I'm sure you're probably aware that a command set was part of the original
ATA and has persistently been enhanced over time. I think that it pays more
homage to the command set part of the specification rather than the
physical interface.

Re: formatting MFM drives on a IBM PC

[Chuck Guzis via cctalk]

On 09/29/2017 06:07 AM, Paul Koning wrote:

> There are chips that convert between serial and parallel ATA; one of
> those could perhaps be used.  I'm more used to applying them for
> attaching a serial ATA controller to a parallel ATA drive, but
> possibly they might work in the other direction as well.  Not clear
> if they are still common products, given that parallel ATA is pretty
> old, but they may still be available.

Oh, I've got a pile of such converters--workability is variable.

What I was saying is that I've never seen an ISA interface card to a
SATA drive.  Have you?

--Chuck

Re: cctalk Digest, Vol 39, Issue 2

[Adrian Graham via cctalk]

Hi Andrea,

I assume that's a message for me about my strange grounding issue?

I'd already replaced the caps in that startup circuit, it's one of the
first things you do when troubleshooting a non-booting Newbrain. In this
case it seemed to be some electrolytic spill from the original leaky caps
that I'd missed when cleaning the first time - the traces for this circuit
are on top of the board and I'd only cleaned the solder side.

Cheers :)

Adrian

On 29 September 2017 at 13:07, shad via cctalk 
wrote:

> Hello,
> explanation is easy.
> Old electrolytic will have a bigger current leakage, i.e. the unwanted
> amount of current which flows through it.
> With resistances having high value, the small current is completely eated
> by the leakage, thus never charging the capacitors.
> As you are connecting the probes, each having around 1M ohm impedance, you
> are lowering the effective resistance, thus charging a little.
>
> Solution: replace both capacitors with same value.
>
> Andrea
>



-- 
adrian/witchy
Owner of Binary Dinosaurs, the UK's biggest home computer collection?
www.binarydinosaurs.co.uk

Re: formatting MFM drives on a IBM PC

[Paul Koning via cctalk]

> On Sep 28, 2017, at 8:36 PM, Chuck Guzis via cctalk  
> wrote:
> 
> On 09/28/2017 05:12 PM, Jules Richardson via cctalk wrote:
>> On 09/27/2017 09:59 AM, Ethan via cctalk wrote:
>>> The idea of IDE, as my understanding, is the controller that existed
>>> as an
>>> ISA card was moved onto the actual drive, and then what became the
>>> controller was mostly just extending the ISA bus over to the drive.
>> 
>> I actually have an IDE "controller" somewhere which is just a tiny PCB
>> with an ISA connector on one side and a 40 pin IDE connector on the
>> other, along with a couple of ICs (presumably buffers/latches, but I
>> don't know without finding it).  It's somewhat unusual, given that IDE
>> ports were normally included as part of multi-I/O boards, or (a little
>> later) often incorporated into the motherboard.
> 
> IDE used to be called "ATA" - "AT Attachment"; i.e. something tailored
> to the PC AT (5170) 16-bit ISA bus.
> 
> What I find perplexing is the acronym "SATA" for "Serial ATA".  The name
> would imply that a drive can be connected to a 5170, but I'm not aware
> of any SATA adapters for the 5170 PC/AT.

There are chips that convert between serial and parallel ATA; one of those 
could perhaps be used.  I'm more used to applying them for attaching a serial 
ATA controller to a parallel ATA drive, but possibly they might work in the 
other direction as well.  Not clear if they are still common products, given 
that parallel ATA is pretty old, but they may still be available.

paul

Re: formatting MFM drives on a IBM PC

[Peter Corlett via cctalk]

On Thu, Sep 28, 2017 at 05:36:40PM -0700, Chuck Guzis via cctalk wrote:
[...]
> What I find perplexing is the acronym "SATA" for "Serial ATA". The name would
> imply that a drive can be connected to a 5170, but I'm not aware of any SATA
> adapters for the 5170 PC/AT.

SATA has a different electrical interface, but otherwise speaks the same
protocol as the older (P)ATA protocol. Converters are cheap and readily
available.

So yes, you could stick a SATA disk in your old 5170, assuming that the BIOS
doesn't immediately faint when presented with a very large disk.

Re: cctalk Digest, Vol 39, Issue 2

[shadoooo via cctalk]

Hello,
explanation is easy.
Old electrolytic will have a bigger current leakage, i.e. the unwanted
amount of current which flows through it.
With resistances having high value, the small current is completely eated
by the leakage, thus never charging the capacitors.
As you are connecting the probes, each having around 1M ohm impedance, you
are lowering the effective resistance, thus charging a little.

Solution: replace both capacitors with same value.

Andrea

Re: formatting MFM drives on a IBM PC

[Christian Corti via cctalk]

On Thu, 28 Sep 2017, Chuck Guzis wrote:

"Low level format" is pretty much a relic of the old non-servo MFM
drives.   I recall that early Maxtor IDE drives implemented a LLF


Lowlevel formatting has to be done for *all* ST-506 interface drives (e.g. 
"MFM" and "RLL" drives). It is the disk controller that needs to write its 
sector and track layout to the drive (ID marks, data marks, GAPs, CRC, ECC 
and so on). This is also true for SMD drives, for example. So it didn't 
make much sense in selling preformatted drives until when disk drives
exposed only the disk blocks to the host. Whether a drives uses servo 
information or not is irrelevant. I don't consider writing servo 
information as lowlevel formatting.


Christian

Re: Reviving ancient MFM drives (was Re: formatting MFM drives on a IBM PC)

[Christian Corti via cctalk]

On Thu, 28 Sep 2017, Geoffrey Oltmans wrote:

Speaking of I've got a couple of old MFM drives (10 and 20 MB of a
variety whose name and model #'s escape me, I wanna say Tandon, but not
sure). They seem to work fine when I initially format and partition, but as
they run for a while, they get more and more unreliable. It seems to be a
function of how long they've been running for rather than a predictable
pattern of bad tracks sectors? Are there any good sources of
troubleshooting info at the controller level for these old drives?


Well, that's normal. The usual procedure is to let the drive warm up for 
10-20 minutes before formatting. And it is also normal for some models 
that they must be reformatted after, say, a couple of months or years, 
depending on make and manufacturer. The Rhodime 50MB drive in my IBM 8550 
is such a beast. My procedure is to run Norton CALIBRAT to reformat the 
drive losslessly.


Christian

Re: HP 7970E - interest to split?

[Steve Malikoff via cctalk]

Chuck said:
> On 09/28/2017 08:57 PM, Anders Nelson via cctalk wrote:
>> Update: I bought the Kennedy 9800 as it pushed all my buttons at once.
>>
>> Now I'm looking for 8" mag tapes/reels that will fit! Anyone know where I
>> can find these, maybe 3pcs? I could laser-cut some frosted acrylic or
>> machine some frosted polycarbonate I suppose but I'd rather just buy it,
>> plus that would include a dust cover.
>
> Why not just laser-cut down a 10.5" reel?  The hub dimensions are the same.
>
> --Chuck

Or take the reels to a engineering shop and ask them to turn them down on a 
lathe,
it should be a very simple job for them. Besides, there are lots of 10.5" dia 
tapes
available on eBay, and I'm sure I've seen sellers with 8" tape reels.

On my Kennedy 9000s the rubber O-rings have expanded on all the spindles and a
reel has a lot of trouble being pushed on and removed. I plan to replace them 
with
neoprene O-rings of the original size. These are readily available and cheap 
from
bearing supplies stores, I'll get a range of close sizes and find the right one.

Steve.