Re: Does the White Russian 0.9 DynDNS client suck just as much?
On 6/14/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
Of course, logging into the DynDNS UI is an easy way to manage my
DynDNS entries. The whole point of installing OpenWRT/ez-ipupdate
(with which fact I opened my initial post on this subject) was to
avoid having to do this by automating the update process!
I've been using zonedit and a cronjob script to check if my router's IP
changed.
It's got some old cruft in it.
#!/bin/sh
# What's my host-ip?
dig @ns15.zoneedit.com $HOST. | grep ^$HOST | awk
'{print $NF}' /tmp/zonedit.dig
# What's my IP?
lynx -dump -accept_all_cookies http://www.whatismyip.com | egrep '[0-9]' |
egre
p -iv 'page.|Lines|http:|explained|Anywher|guard|WhatIsMyIP.com' | awk
'{print $
NF}' /tmp/zonedit.ip
#lynx -source http://www.dnsstuff.com/ | grep 'Your IP' | cut -d' ' -f3 | tr
-d
'[A-z/:]' /tmp/zonedit.ip
# compare them
diff /tmp/zonedit.dig /tmp/zonedit.ip /tmp/zonedit.mail
if [ $? -eq 0 ]
then
# no update needed
exit 0
fi
# mail status!
echo dig /tmp/zonedit.mail
cat /tmp/zonedit.dig /tmp/zonedit.mail
echo ip /tmp/zonedit.mail
cat /tmp/zonedit.ip /tmp/zonedit.mail
# need to update
#lynx -source -auth=$user:$password
http://dynamic.zoneedit.com/auth/dynamic.h
tml?host=$HOST /tmp/zoneedit
wget -O - --http-user=$user--http-passwd=$password
http://dynamic.zoneedit.co
m/auth/dynamic.html?host=$HOST
cat /tmp/zoneedit /tmp/zonedit.mail
mail -s 'dd-zonedit' [EMAIL PROTECTED] /tmp/zonedit.mail
rm /tmp/zonedit.mail
___
gnhlug-discuss mailing list
gnhlug-discuss@mail.gnhlug.org
http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
Sorry to dredge it all up, but there was a discussion some time back about an app that was supposed to be a drop in replacement for ES including all of the calendaring crap. Does anyone remember what that was? PostPath (http://www.postpath.com) advertises on their homepage: The only Exchange Server™ alternative to deliver drop-in Microsoft(r) interoperability across the email ecosystem. A free 12 user version can be downloaded from the site When I looked at this though, about 6-9 months ago, I found out that this still relies on an MS active directory infrastructure already in place. I did speak with a salesman from the company and he did tell me that a completely stand alone version was planned for release in 2007. Hope this helps. Mark ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
Another option is Open Xchange. It's actually a bit of a superset of Exchange in that it offers some features not available in Exchange. I've installed this for a client that has Linux servers and Windows desktops and it works well with Outlook! Their web site is at http://www.open-xchange.com/ Dan [EMAIL PROTECTED] wrote: The two that I know of off the top of my head are: Scalix http://www.scalix.com Zimbra http://www.zimbra.com Both have their caveates. HTH, Kenny -- Original message -- From: Steven W. Orr [EMAIL PROTECTED] Sorry to dredge it all up, but there was a discussion some time back about an app that was supposed to be a drop in replacement for ES including all of the calendaring crap. Does anyone remember what that was? TIA -- Time flies like the wind. Fruit flies like a banana. Stranger things have .0. happened but none stranger than this. Does your driver's license say Organ ..0 Donor?Black holes are where God divided by zero. Listen to me! We are all- 000 individuals! What if this weren't a hypothetical question? steveo at syslang.net ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Does the White Russian 0.9 DynDNS client suck just as much?
We do have a page specifically for clients that are compliant to our protocol. The UNIX specific client page is: http://www.dyndns.com/support/clients/unix.html I asked our client certification guy what he would recommend for OpenWRT and he suggested the inadyn client. -- Cole Tuininga [EMAIL PROTECTED] http://www.code-energy.com/ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
On 6/15/07, Mark Mcsweeney [EMAIL PROTECTED] wrote: PostPath (http://www.postpath.com) advertises on their homepage: On 6/15/07, Dan Coutu [EMAIL PROTECTED] wrote: Another option is Open Xchange. It's actually a bit of a superset of Exchange in that it offers some features not available in Exchange. Anyone know if the above either supply their own Extended MAPI provider software, or implement the Exchange MAPI wire protocol? If not, you're still stuck using PST files with Outlook. PST = BAD. Most of the Exchange replacements I've encountered suffer from this problem. They implement SMTP and IMAP, which would be enough for most client software. But Outlook started life as the Exchange Client software, and it still reflects that, in that it doesn't really work well unless it's talking to an Exchange server, or something else that acts like one (i.e., implements Extended MAPI). -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Does the White Russian 0.9 DynDNS client suck just as much?
Date: Fri, 15 Jun 2007 08:42:28 -0400
From: Tom Buskey [EMAIL PROTECTED]
I've been using zonedit and a cronjob script to check if my router's IP
changed.
It's got some old cruft in it.
Please, please, please, folks! Don't even THINK about doing stuff
like this. (Newbies, cover your eyes!)
# What's my IP?
lynx -dump -accept_all_cookies http://www.whatismyip.com | egrep '[0-9]' |
Most DHCP clients will store the current IP in some kind of
lease/cache file. DHCP lease files are usually pretty easy to parse.
But, if you really must get your IP address the hard way, you could
use something with fewer teeth than scraping www.whatismyip.com:
# ifconfig `route | grep default | awk '{print $8}'` | \
grep inet | awk '{print $2}' | cut -d : -f 2
Many DHCP clients can also be told to run a certain command whenever
the IP address changes. On White Russian 0.9, if the file
/etc/udhcpc.user exists, udhcpc will run it whenever it acquires a new
IP address. (In this script, the new IP address is passed as the
value of $ip.)
In this sense, DynDNS clients such as ez-ipupdate can be said to be
misimplemented. ez-ipupdate, for example, uses polling to check if
the specified interface's IP address has changed. The proper way to
perform this check would be to include a call to ez-ipupdate in the
script run by the DHCP client. That way, ez-ipupdate would receive
notice of IP changes as soon as they occured, and wouldn't have to
keep checking to see if the address has changed. (This makes me
wonder if I shouldn't be running ez-ipupdate in -d daemon mode.)
But, all aside, arcane hacks do make interesting reading for
nerd-infested mailing lists. :^)
___
gnhlug-discuss mailing list
gnhlug-discuss@mail.gnhlug.org
http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
On 6/15/07, Drew Van Zandt [EMAIL PROTECTED] wrote: PostPath says it's a wire-level reverse-engineer, so no PST files. O... shiny. /me moves Look at PostPath up a few notches on my to-do list (Unfortunately, that still means Possibly not within this decade. ~sigh~) -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
PostPath says it's a wire-level reverse-engineer, so no PST files. --DTVZ On 6/15/07, Ben Scott [EMAIL PROTECTED] wrote: On 6/15/07, Mark Mcsweeney [EMAIL PROTECTED] wrote: PostPath (http://www.postpath.com) advertises on their homepage: On 6/15/07, Dan Coutu [EMAIL PROTECTED] wrote: Another option is Open Xchange. It's actually a bit of a superset of Exchange in that it offers some features not available in Exchange. Anyone know if the above either supply their own Extended MAPI provider software, or implement the Exchange MAPI wire protocol? If not, you're still stuck using PST files with Outlook. PST = BAD. Most of the Exchange replacements I've encountered suffer from this problem. They implement SMTP and IMAP, which would be enough for most client software. But Outlook started life as the Exchange Client software, and it still reflects that, in that it doesn't really work well unless it's talking to an Exchange server, or something else that acts like one (i.e., implements Extended MAPI). -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Does the White Russian 0.9 DynDNS client suck just as much?
On Fri, 2007-06-15 at 11:03 -0400, Thomas Charron wrote: On 6/15/07, Stephen Ryan [EMAIL PROTECTED] wrote: Actually, that gives the IP address of this machine, not the IP address of the router, which, given that it's IP address might change, is quite likely doing address translation before hitting the public internet. In the case of my home network, running through some cheap consumer-grade Netgear job, the only way to find out the public IP address is to scrape some web page, and whatismyip.com is probably the easiest one to get at. It's certainly easier than getting the password-protected front page the router serves up! *Pt* White Russian runs on the router. :-) oh nevermind :-) ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Does the White Russian 0.9 DynDNS client suck just as much?
On 6/15/07, Thomas Charron [EMAIL PROTECTED] wrote: On 6/15/07, Stephen Ryan [EMAIL PROTECTED] wrote: Actually, that gives the IP address of this machine, not the IP address of the router, which, given that it's IP address might change, is quite likely doing address translation before hitting the public internet. In the case of my home network, running through some cheap consumer-grade Netgear job, the only way to find out the public IP address is to scrape some web page, and whatismyip.com is probably the easiest one to get at. It's certainly easier than getting the password-protected front page the router serves up! *Pt* White Russian runs on the router. :-) FiOS uses another brand (Acctron?). It's got an IP to coax connector for IPTV. Each TV set top box on coax has an IP address (192.168.1.100 and up) ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Does the White Russian 0.9 DynDNS client suck just as much?
On 6/15/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
Date: Fri, 15 Jun 2007 08:42:28 -0400
From: Tom Buskey [EMAIL PROTECTED]
I've been using zonedit and a cronjob script to check if my router's IP
changed.
It's got some old cruft in it.
Please, please, please, folks! Don't even THINK about doing stuff
like this. (Newbies, cover your eyes!)
There is a reason for doing this way. I'm open to suggestions. Read on.
# What's my IP?
lynx -dump -accept_all_cookies http://www.whatismyip.com | egrep
'[0-9]' |
Most DHCP clients will store the current IP in some kind of
lease/cache file. DHCP lease files are usually pretty easy to parse.
But, if you really must get your IP address the hard way, you could
use something with fewer teeth than scraping www.whatismyip.com:
# ifconfig `route | grep default | awk '{print $8}'` | \
grep inet | awk '{print $2}' | cut -d : -f 2
If I do that on my linux box it'll *always* say 192.168.1.35 because it's
behind my FiOS router that I can't login to. I don't have direct access to
the IP that FiOS gives the router via IP. So, I go to a web site that tells
me what IP is on the other side of the NAT. I'd love to have a better
solution that works.
The lease files can be parse, but the ISC DHCP server docs say they will not
stay the same so don't parse them. Of course you can say the same about the
Linux API which changes all the time. If it works, use it fix it when it
doesn't.
___
gnhlug-discuss mailing list
gnhlug-discuss@mail.gnhlug.org
http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Does the White Russian 0.9 DynDNS client suck just as much?
(sorry, meant to send this to the list)
On Fri, 2007-06-15 at 10:35 -0400, [EMAIL PROTECTED] wrote:
Date: Fri, 15 Jun 2007 08:42:28 -0400
From: Tom Buskey [EMAIL PROTECTED]
I've been using zonedit and a cronjob script to check if my router's IP
changed.
It's got some old cruft in it.
Please, please, please, folks! Don't even THINK about doing stuff
like this. (Newbies, cover your eyes!)
# What's my IP?
lynx -dump -accept_all_cookies http://www.whatismyip.com | egrep '[0-9]' |
Most DHCP clients will store the current IP in some kind of
lease/cache file. DHCP lease files are usually pretty easy to parse.
But, if you really must get your IP address the hard way, you could
use something with fewer teeth than scraping www.whatismyip.com:
# ifconfig `route | grep default | awk '{print $8}'` | \
grep inet | awk '{print $2}' | cut -d : -f 2
Actually, that gives the IP address of this machine, not the IP address
of the router, which, given that it's IP address might change, is quite
likely doing address translation before hitting the public internet. In
the case of my home network, running through some cheap consumer-grade
Netgear job, the only way to find out the public IP address is to scrape
some web page, and whatismyip.com is probably the easiest one to get at.
It's certainly easier than getting the password-protected front page the
router serves up!
___
gnhlug-discuss mailing list
gnhlug-discuss@mail.gnhlug.org
http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: OT: PC Gigabit Throughput Question
On 06/14/2007 08:30 PM, Ric Werme wrote: A 1500 byte Ethernet message is 12,000 bits, and hence only 12 usec of wire time. If you need full performance and can use Jumbo Frames of 9,000 bytes (72 usec) so much the better. The other advantage of jumbo frames is that there's less packet overhead so more data/time, and far less overhead for the CPU to assemble the frame, calculate checksums, etc. The speed in my testing wasn't necessarily faster, but you did save 10-20% CPU load when running at high data rates. Devices that have a lot of large-IO blocks (file servers) would have a boost in improvement when switching to jumbo frames. We'd be using it on our cluster, but some of the older nodes we have don't support jumbo frames on the Ethernet chipset. Once those get retired, we'll probably move to jumbo frames. -Mark ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Does the White Russian 0.9 DynDNS client suck just as much?
On Fri, June 15, 2007 11:03 am, Thomas Charron said: On 6/15/07, Stephen Ryan [EMAIL PROTECTED] wrote: Actually, that gives the IP address of this machine, not the IP address of the router, which, given that it's IP address might change, is quite likely doing address translation before hitting the public internet. In the case of my home network, running through some cheap consumer-grade Netgear job, the only way to find out the public IP address is to scrape some web page, and whatismyip.com is probably the easiest one to get at. It's certainly easier than getting the password-protected front page the router serves up! *Pt* White Russian runs on the router. :-) -- -- Thomas Actually, the router to the ISP is the cable or DHL modem, not the wrt54g. -- John Abreau / Executive Director, Boston Linux Unix IM: [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] / [EMAIL PROTECTED] Email [EMAIL PROTECTED] / WWW http://www.abreau.net / PGP-Key-ID 0xD5C7B5D9 PGP-Key-Fingerprint 72 FB 39 4F 3C 3B D6 5B E0 C8 5A 6E F1 2C BE 99 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
FiOS and MythTV? WAS: Re: Does the White Russian 0.9 DynDNS client suck just as much?
FiOS uses another brand (Acctron?). It's got an IP to coax connector for IPTV. Each TV set top box on coax has an IP address (192.168.1.100 and up) Hm. Do you think it'd be possible to use this as a signal source for a MythTV box? brain.gears[0].setMotion(new Motion.turning()); ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: FiOS and MythTV? WAS: Re: Does the White Russian 0.9 DynDNS client suck just as much?
On 6/15/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: FiOS uses another brand (Acctron?). It's got an IP to coax connector for IPTV. Each TV set top box on coax has an IP address (192.168.1.100 and up) Hm. Do you think it'd be possible to use this as a signal source for a MythTV box? brain.gears[0].setMotion(new Motion.turning()); I've thought about that too. There is a standard for what FiOS is doing (I think it's IPTV) and the coax IP connection in the router is touted in sales materials. However, beyond a ping, I haven't been able to get a response from the set top boxes. I'd probably have to sniff the coax to see anything. Frankly, I don't want expend effort that might void my contract :-) ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
Ben Scott [EMAIL PROTECTED] writes: On 6/15/07, Drew Van Zandt [EMAIL PROTECTED] wrote: PostPath says it's a wire-level reverse-engineer, so no PST files. O... shiny. /me moves Look at PostPath up a few notches on my to-do list (Unfortunately, that still means Possibly not within this decade. ~sigh~) If even a portion of following is true, I'd be an extremely happy sysadmin: The server's high performance (compared with Exchange) and ease-of-backup enables the use of low-cost storage, server consolidation, and significantly larger user data-stores so that PST-file use can be reduced or eliminated. Also, the server's flexible translation between Microsoft (ESTMP) and standard (SMTP) email transports, together with a highly configurable PostFix mail transport agent (MTA), enables the use of standards-based virus-filters and archiving systems, eliminating the need for Outlook journaling or proprietary APIs. Somethings to note: - High performance as compared to Exchange is not difficult to achieve :) - Ease of backup is a major win compared to Exchange - Reducing or eliminating PST file use is huge - Eliminating the need for Outlook journaling and the use of MS APIs is huger - The acknowledgement of the use of Postfix (or any mainstream open source MTA) is a great endorsement - The actual use of a mainstream MTA means we can probably tweak this thing to our heart's content! - There is no mention of IMAP capability, nor of calendaring, yet they claim Drop-in, plug-compatible replacement. (There is a POP3 server though) - They do discuss the ability to work with both an existing AD server, and Blackberry server. - The admin manual has details on backing up via tar, dump, xfsdump, legato7, fs, and Symantec BackupExec, which means that Bacula and AMANDA should work just fine. After looking over their FAQ (which is available only as a PDF http://static.postpath.com/gems/apptranMain/PostPathFAQv04.pdf and their Admin Guide http://static.postpath.com/gems/apptranMain/PostPathAdminGuide.pdf I'm left with some conflicting thoughts. I think it's great they've got this product, and I think not having to deal with Exchange is great. However, there is no Exchange-PostPath Feature comparison. Calendaring is HUGE in the MS world. MS users can not live without it. Yet, there is no mention of this one killer feature of Exchange that I found. Next, all the documentation seems to be geared those used to managing Exchange, and therefore assumes little to no Linux, UNIX, or FOSS familiarity. Yet there is no mention of which e-mail clients PostPath is compatible with other than Outlook, and there is no mention of how a non-Windows desktop (Mac, Linux) could or should connect to the PostPath server. Their FAQ is hardly useful[1], their Admin Guide seems not bad. But there are still a lot of unanswered questions, like, what if I'm in a non-windows environment and want to provide an Exchange-like service ? Can I do that? If so, what client-side software is compatible? Can I use a combination of IMAP client and Web-browser to deal with e-mail and calendaring? Will Evolution work? Does it need the Exchange Connector software, or is that unnecessary? So, at this point, I think what they have is something that probably works really well as an e-mail server for Outlook-based clients, is far easier to back up. And in some ways that alone is a major win. However, I'm left with the feeling that this product is more for people who don't know and understand e-mail beyond the level a point-n-click than those of us who have pulled our hair out tweaking sendmail.cf and making postfix jump through hoops over the years. -- Seeya, Paul [1] A FAQ from a commercial entity which is mostly useless is not a surprise. Commercial entities seem to treat the concept of a FAQ as Questions we'd prefer to answer for you, but you're not likely to actually ask because you really don't care about *these* questions. But we need to provide something to make you feel like we've been honest and upfront so you don't notice we're lying through our teeth. ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
Oooh, interesting. Open Xchange does NOT speak MAPI. You need to use either POP or IMAP for email connectivity. It uses WebDAV for the calendar, shared folders, and other features. Dan Drew Van Zandt wrote: PostPath says it's a wire-level reverse-engineer, so no PST files. --DTVZ On 6/15/07, Ben Scott [EMAIL PROTECTED] wrote: On 6/15/07, Mark Mcsweeney [EMAIL PROTECTED] wrote: PostPath (http://www.postpath.com) advertises on their homepage: On 6/15/07, Dan Coutu [EMAIL PROTECTED] wrote: Another option is Open Xchange. It's actually a bit of a superset of Exchange in that it offers some features not available in Exchange. Anyone know if the above either supply their own Extended MAPI provider software, or implement the Exchange MAPI wire protocol? If not, you're still stuck using PST files with Outlook. PST = BAD. Most of the Exchange replacements I've encountered suffer from this problem. They implement SMTP and IMAP, which would be enough for most client software. But Outlook started life as the Exchange Client software, and it still reflects that, in that it doesn't really work well unless it's talking to an Exchange server, or something else that acts like one (i.e., implements Extended MAPI). -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Recommended PCI gigabit ethernet card? OT: PC Gigabit Through put Question
On 6/15/07, Mark Komarinski [EMAIL PROTECTED] wrote: I haven't checked to see what PCI-X/PCI-E does, but I've hit pretty high speeds with it (see below). I looked it up last night. According to the always reliable Wikipedia, PCI-X brings the bus clock to 133 MHz. Still 64-bit. So 8512 megabit/sec before overhead. PCIe (PCI Express) comes in more flavors than ice cream, but the x1 slots are given as 250 megabyte/sec. (Note bytes vs bits in the above. Not knowing the implementations details, I'm presenting the figures as given.) -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
MonadLUG meeting notes 14 June 2007
The June meeting of CentraLUG, the Peterborough chapter of the Greater New Hampshire Users Groups, was held last night, Thursday, 14 June 2007, Charlie Farinella presiding. Our presenter was Ed Haynes, with Wind River in Nashua. Wind River is one of the organizations which (as I remember them) a few years ago was confronted with a business-model choice by the rise of Linux. More on that later. The meeting was all about Linux, realtime, and Linux in realtime. Realtime: when a computer has to deliver a result in a predictable amount of time. In some cases the amount of time may be short, so realtime may mean fast response. In many important cases, however, the amount of time may need to be *guaranteed* -- even to the point of being less than fastest response. The keyword is deterministic. Fastest response 99.99% of the time may not cut it if just one response is late, or if just one interrupt gets lost. Some applications (hmmm... a rocket engine?) might fail totally if that one late response or lost interrupt happens at the wrong time -- even if the application has run for hundreds or thousands of hours with no apparent problems. Ed explained that Linux isn't (by design) a realtime operating system. And demonstrated it! He had a RHEL host system running on a laptop, a target box named fred, a Via 7 x86 embedded system running Linux in several flavors (it picks up its kernel via PXE boot, much like a thin client does in an LTSP environment), and even a projector connected to the laptop -- which worked. (Amazing. :) Ed showed us fred running a 2.6.14 kernel, pushed by the host laptop to measure interrupt response time, first running undisturbed and then running while being subjected to a PING flood. Undisturbed, the response times were pretty respectable, with a distribution, a jitter (if my notes are right) of something like plus or minus 14 microseconds. But when subjected to the PING flood the responses went all over the place: the jitter increased to as much as 512 microseconds. What optimizes throughput in a general- purpose operating system can make realtime performance completely unacceptable. Poor fred. Ed then loaded fred with a Linux kernel which incorporates Andrew Morton's PREEMPT-RT patches, as updated (and contributed back to the community) by Wind River. Unloaded response time was essentially unchanged, as was jitter at about 14 us. But now the PING flood caused the jitter to increase only to 35 us or so. Watching these effects on a real system was an eye-opening education. (Note that PREEMPT-RT improves jitter, but that Linux still cannot be characterized as deterministic. Good enough for many tasks, no doubt, but I still wouldn't want Linux running my autopilot.) There's another approach, which Ed described but did not demonstrate: running Linux on top of a small, deterministic realtime kernel. In Wind River's hands this is partly GPL, partly proprietary. There were a number of small discussions after the presentation (and a QUIZ! :). We complimented Ed on giving a commercial- free presentation on an important Linux topic, and I especially enjoyed hearing about Wind River's success with embracing Linux and the free software/make money by support business model. Not every firm confronted by customer demand for support of free software has figured out how to make good business with it. A delightful evening. Thank you, Ed! And congratulations to Charlie: a dynamite program. Respectfully submitted, -Bill ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Linux Exchange server replacement.
On 6/15/07, Paul Lussier [EMAIL PROTECTED] wrote: Calendaring is HUGE in the MS world. MS users can not live without it. Yet, there is no mention of this one killer feature of Exchange that I found. It might be worth noting that Outlook implements calendaring as just another class of the same IPM object that regular messages are. Meeting invitations are just special hidden messages. Free/Busy Information is just IPM objects written to a hidden Public Folder. The Exchange server itself has very little awareness of the calendaring. So if they've got the Exchange wire protocol working, they might not need to worry about it; it's mostly done in Outlook. (Of course, there are probably details that matter, but I figured I'd toss this out there). But there are still a lot of unanswered questions, like, what if I'm in a non-windows environment and want to provide an Exchange-like service ? Given the reported Active Directory requirement, I'd say you're in trouble. ;-) -- Ben ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: MonadLUG meeting notes 14 June 2007
Bill Sconce writes: There's another approach, which Ed described but did not demonstrate: running Linux on top of a small, deterministic realtime kernel. In Wind River's hands this is partly GPL, partly proprietary. If you want a hard-realtime system with access to Linux, I highly recommend RTAI. --kevin -- GnuPG ID: B280F24E God, I loved that Pontiac. alumni.unh.edu!kdc -- Tom Waits ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Recommended PCI gigabit ethernet card? OT: PC Gigabit Through put Question
On Thu, 2007-06-14 at 22:16 -0400, Paul Lussier wrote: Tom Buskey [EMAIL PROTECTED] writes: On top of that, if hdparm says timed disk writes are around 40MB, what could you see for sustained download speeds? Maybe a static cached webpage could saturate a gig connection, sustained 5 gig http download couldn't right? Anyone have real world answers for that stuff? What if you're downloading to RAM disk? What if you're building a router? The traffic never hits the disk, so drive performance is irrellevent here. For each individual node, the speed of the bus and how fast the packet can be transferred to the disk is important, but for the total bandwidth of the wire, it is nice to have it as fast as possible while still preserving things like reliability, reasonable physical length of the wire for that speed, etc. If I remember correctly, after a packet comes across, the controller is supposed to wait some period of time before grabbing the wire again. This allows some other controller time to grab the wire. So even a 10Gbit wire is not really going to transfer data at a full 10Gbits continuously. I remember a case where Sun was beating Digital's (and other vendors) pants off on ETHERNET transfers. Then we did a study of a Sun system on the wire, and found out that they were not waiting this entire period between packet transfers, so would grab the wire a disproportionate amount of the time. When they corrected this problem, their ETHERNET capability dropped back to normal. Digital used to talk about balance of a system. Balancing CPU power, with size of memory, size of cache, speed of disks and bus. Putting a super-fast CPU on a bus that could not deliver the data meant that you were wasting a lot of power. Likewise a super-fast ETHERNET controller. AFAIK it was accepted and anticipated that an ETHERNET controller was never going to effectively move wire speed at any given time onto or off of the disk. That is one of the reasons why there are so many copy to moves inside of the kernel, but it did mean that if you sent the bits over the wire at wire speed the controller would have half a chance of receiving them correctly and making sure they went where they were supposed to go, then free up the wire for someone else to use. Maybe engineering expectations have changed since the days of 10Mbit ETHERNET, but I do remember having those discussions with the engineering staff. And I agree that if you want to have the fastest path to your disk, having a bus that can support it is a place to start, no matter what ETHERNET controller you have. md ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Recommended PCI gigabit ethernet card? OT: PC Gigabit Throughput Question
A lot of what Maddog wrote pertains more to coax or hub based Ethernet (CSMA/CD, Carrier Sense, Multiple Access with Collision Deterction) which is true Ethernet. Twisted pair media used with switches and routers I believe is all Single Access and has no collisions. If I remember correctly, after a packet comes across, the controller is supposed to wait some period of time before grabbing the wire again. I've never learned much about Twisted Pair. This is true for coax, and probably true for Twisted pair. I've even forgotten the name of that delay, something like interframe gap. I think one thing it does is allows transceivers with slightly different clocks to keep the packets distinct. On CSMA it helps give other stations a chance to get a word in edgewise. You said that. On 10Base-2, the classic 10 Mbps Ethernet, the gap is 10 usec, 100 bits. It may be the same on 100BaseT, I think 1000BaseT it had to be reduced. AFAIK it was accepted and anticipated that an ETHERNET controller was never going to effectively move wire speed at any given time onto or off of the disk. I think it was worse than that - for a long time an accepted rule of thumb was that an Ethernet should average over no more than 10% of full bandwidth with peaks of 50% or so to keep the collision rate low. There's more to getting access to the wire than just that interframe gap. People were rather surprised to find it worked pretty well at much higher rates, it turns out that a high collision rate doesn't impact throughput much, each costs only 51 usec. One odd effect that is a spinoff of the collision avoidance mechanism is the capture effect. If a station wants to get the wire and collides with another station, each backs off a random amount up to 2 raised to the number of collisions times 51 usec or so. When one station does get the wire, its backoff counter resets to zero and it has a better chance of getting the wire at the next collision. This can lead to one system getting a disproportionate amount of time on the wire. DEC even identified some cases where groups of systems, each incapable of saturating the wire could together and would form ephemeral gangs that captured the wire. With the advent of switches that buffer frames, most Ethernet installations are no longer true ethernet, and most of the issues of capture effects and collision issues have gone away, but have been replaced by problems with the buffering being woefully inadequate. A Linux-based router will have plenty of buffering, but routing 100 byte frames on multiple GbE wires would be interesting (100 bytes == 800 bits == 800 nsec.) It took my all-time favorite computer 13,500 nsec to divide a pair of 36 bit numbers (the first PDP-10). At least it had a divide instruction. On a lot of modern architectures your lucky to have an approximation of the reciprocal of the divisor to start with. Maybe engineering expectations have changed since the days of 10Mbit ETHERNET, but I do remember having those discussions with the engineering staff. Lots has changed - going from 10 Mbps to 10 Gbps is that three orders of magnitude change the paradigm event. That 51 usec collision time determines the maximum size of an CSMA/CD network. You want to have a colliding packet be on the wire long enough so that both stations see the collision. Scaling that down as speeds go up would mean a 10 Gbps network would be 1/1000th the physical size of ye olde 10 Mbps network. Keeping the collision time the same would mean giving up 1000 times more bandwidth, which is enough to be a problem on busy nets. And on top of all that, CSMA/CD is shared, and people are more concerned about security these days. And since the cost of routers and switches has come down lots, they now rule the office. Ethernet is dead - long live Ethernet And I agree that if you want to have the fastest path to your disk, having a bus that can support it is a place to start, no matter what ETHERNET controller you have. Big battery backed caches are important too, at least if you want to trust the data on your server. A UPS that provides power for the server to write all cached data is adequate too. -Ric Werme ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Non Linux but network tech question
On Thu, 14 Jun 2007, sean wrote: Here is the problem. The local ISP they use, Comcast, gives them a free connection, but the address is dynamic. When on that time the address renews and is not the same, they link to the online catalog cannot be reached. Looking it over the link is specified by an IP address. I also use Comcast and my IP rarely changes. I think I may be on the same IP now for maybe a year and a half to two years. The trick is... keep your equipment running. Generally I've found that the Comcast DHCP server pretty much respects the lease renewals as long as you're there. Throw your router and cable modem on a UPS and just leave it be. A cheap UPS will keep those two devices running for a long time. -Kenta ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
Re: Recommended PCI gigabit ethernet card? OT: PC Gigabit Throughput Question
There are still collisions (of a sort) even on full-duplex switched networks. Two 10 Mbit devices can't talk full speed to the same 10 Mbit conversation partner, obviously. Store-and-forward switches and routers help with short-term congestion, but even without 2-to-1 bottlenecks, most switches can't maintain wirespeed on all ports simultaneously. Wirespeed routing with a Linux box isn't practical with real high-speed stuff, even dedicated hardware has trouble keeping up. (Even a big box would have trouble with more than 5 or 6 GbE cards, let alone 10 GbE.) 10 GbE actually has something along the lines of padding bits here and there in the middle of packets, not just between frames, so that they can be dropped (or added to, I think?) if the clocks on the two ends of the link aren't quite close enough - it's been a while since I worked on that hardware, so I don't remember very well. In any case, tuning your Ethernet is a valuable exercise for latency reasons, not just bandwidth reasons...both matter. I miss network hardware. :-) --DTVZ ___ gnhlug-discuss mailing list gnhlug-discuss@mail.gnhlug.org http://mail.gnhlug.org/mailman/listinfo/gnhlug-discuss/
