May 2007 - WLUG - wlug.mailman3.com

Re: [Wlug] Multiple RS232 Com Ports...

by Mike Frysinger

On 5/20/07, Stephen C. Daukas <scd(a)daukas.com> wrote: > I'm wondering if anyone knows how many RS232 devices a "vanilla" Linux > kernel can manage simultaneously. there shouldnt be any real limit ... at work, we have ~24 USB<->RS232 devices hooked up and we use them all simultaneously to interact with some hardware > I'd like to be able to have up to 32 > going at once, with data taken from each device written to its own file via > the standard I/O subsystem. As far as I know, wouldn't Linux simply fork > the appropriate number of driver threads to read as many RS232 ports as are > attached with each device's stream written to a "/dev" file? i'd be more worried about *what* the devices are and *how* you connect your 32 devices to the machine ... making sure linux has proper device driver support for it -mike

May 20, 2007

Multiple RS232 Com Ports...

by Stephen C. Daukas

Hi all! I'm wondering if anyone knows how many RS232 devices a "vanilla" Linux kernel can manage simultaneously. I'd like to be able to have up to 32 going at once, with data taken from each device written to its own file via the standard I/O subsystem. As far as I know, wouldn't Linux simply fork the appropriate number of driver threads to read as many RS232 ports as are attached with each device's stream written to a "/dev" file? Why do I want to do this? Glad you asked... I'm investigating an issue at work that involves our instrumentation lab having to upload/download/calibrate multiple sondes and have them ready for field deployment the next day. Currently, we can do three at a time and this takes about 8-9 hours providing everything goes well. The manufacturer's software application claims to supports the simultaneous upload/config of up to 32 sondes. The application will scan "installed" COM ports looking for recognizable sondes, and present those found to the user. Yes - this is a windows solution, so I first began looking for products that would play with Windows... I began looking for hardware solutions (PCI boards, break-out boxes, etc.) on the net and I found a few that will provide 16 DB-9 RS232 ports with full pin-out support as well as so-called "true" interrupt and FIFO support on the host (via their own custom Windows driver, no doubt). And then I started wondering about how to get all of this to work in a Windows environment where "IT" is the only group allowed to install software and otherwise configure a PC for most users whose biggest concern is email... All this got me thinking about avoiding the whole Windows issue and instead thinking about using Linux to take care of the RS232 part, with the newly created files moved to a Windows box (sneakernet to start with), with the normal post-processing of the data taking place as usual in the Windows environment the staff is used to... I'm hoping an "out of the box" distro will be able to handle say 16 RS232 ports and that Linux-based terminal emulation software is available to simultaneously handle those ports as well so I can capture the data using the appropriate protocols... Anyone know of a similar application using RS232 and Linux, or have some thoughts on this? Thanks! Steve

May 20, 2007

Fwd: Urgent Need for Software QA Instructor in Boston, MA

by albutler33＠netscape.net

Hello all, Here's an opportunity I thought I'd pass along. Al Butler member of WLUG (haven't attended for quite a while) -----Original Message----- From: april01(a)o-s-tech.com To: albutler33(a)netscape.net Sent: Thu, 17 May 2007 8:59 PM Subject: Urgent Need for Software QA Instructor in Boston, MA Dear Aljerin, Open Systems Technology Services has an urgent need for an experienced Software Quality Assurance Instructor. Topics Software development life cycle-the product view Software configuration management (SCM) Software quality assurance Testing, validating and evaluating Special topics Planning, organizing, implementing and managing for SQA ------------------- Location: Boston, MA Date: June 11-13 Rate: $300 day/ 1099 Please let me know ASAP if you are available or know of someone who have experience teaching Linux. Classes will begin at 8am each day. Introduction to Linux, 3 days March 19th - 21st Linux Admin I, 5 days March 26th - 30th Linux Admin II, 5 days April 9th - 13t Rate: $500.00/day Job Description: . If you are available, email your resume (in word format) and availability with a contact number by 5:00pm, Monday, May 21, 2007. Thank you, April Washington Open Systems Technology Services, Inc. Email: April01(a)o-s-tech.com ________________________________________________________________________ Check Out the new free AIM(R) Mail -- 2 GB of storage and industry-leading spam and email virus protection.

May 20, 2007

ALSA hanging (Gentoo AMD64)

by Eric Stein

Hi all, I have a very strange problem. Last night I updated all my packages and rebooted. On boot, alsasound started (boot runlevel), but while trying to restore mixer levels, it hung. I had to boot to a livecd and remove alsasound from boot to even start my system. I tried removing the old state file (in case the format changed and it was breaking because of that), but it wouldn't start without it. glamdring ~ # /etc/init.d/alsasound start * One of the files in /etc/{conf.d,init.d} or /etc/rc.conf * has a modification time in the future! * Loading ALSA modules ... [ ok ] * Restoring Mixer Levels ... * No mixer config in /var/lib/alsa/asound.state, you have to unmute your card! [ ok ] glamdring ~ # cd /var/lib/alsa/ glamdring alsa # l total 9 drwxr-xr-x 3 root root 152 May 17 16:26 ./ drwxr-xr-x 23 root root 568 May 17 03:17 ../ -rw-r--r-- 1 root root 0 May 17 16:26 .keep_media-sound_alsa-utils-0.9 -rw-r--r-- 1 root root 8073 May 17 12:50 asound.state.old drwxr-xr-x 2 root root 144 May 17 12:50 oss/ glamdring alsa # mv asound.state.old asound.state glamdring alsa # cd glamdring ~ # /etc/init.d/alsasound zap * Manually resetting alsasound to stopped state. glamdring ~ # /etc/init.d/alsasound start * Loading ALSA modules ... [ ok ] * Restoring Mixer Levels ... Which is where it hangs. Other alsa programs like alsaconf and alsamixer hang on startup, along with programs that attempt to use ALSA to output sound. I've tried reinstalling ALSA, I've tried revdep-rebuild, I've done modules-rebuild, and I'm at my wit's end. None of it seems to make sense, and Gnome isn't very happy about not having a sound output, so half of my GUI is missing. If anyone has some idea why this could be happening to me, please let me know. Eric

May 18, 2007

OT: HP9k E-class

by Desdinova

A bit OT, if you can reply off-list, that's fine. I just figure there's probably guys who know about crappy old minis here. I've got an E25 and I'm planning to replace the internal scsi drive, it shouldn't be any big deal, but this *is* HP. Are there any gotchas on drive geometry or size that I should watch for? Take care, des

May 17, 2007

Re: [Wlug] Follow-Up to Key Signing Party

by Jamie Guinan

On Thu, 17 May 2007, Eric Martin wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Thanks to everyone who showed up to tonight's key signing party. Now > that we verified everybody had the correct key info and identification, > we actually have to sign each other's keys. We are using the keyserver > pgp.mit.edu. If that isn't your default, you can set it either in > ~/.gnupg/gpg.conf or at the command line for each command by using the > argument > - --keyserver pgp.mit.edu Is the "hkp://" prefix needed in gpg.conf? keyserver hkp://pgp.mit.edu > Below is an excerpt from the gpg Key Signing Party HowTo that explains > things in detail.(http://www.rubin.ch/pgp/kspa/gpg-party.en.html#ss3.8): > > 3.8 How to sign others' keys > > Step 1: Get a copy of the key > > Normally, you'll be working from a keyserver. However if you are signing > the key that is not available on a keyserver, you can use simply import > the key with gpg --import. If you are working with a keyserver, the > following command will download the key from the keyserver into your > public keyring. > > bash$ gpg --keyserver <keyserver> --recv-keys <Key_ID> > > If you get a read error, it means the keyserver is overloaded. Please, > try again in a few seconds. That worked Ok. > > Step 2: Fingerprint and Verify the key > > bash$ gpg --fingerprint <Key_ID> That too. > GPG will print out the fingerprint of the Key with <Key_ID > (the key > you just downloaded). Check the fingerprint against the checklist that > you where given at the party. Note: Don't check the fingerprint on your > checklist against the fingerprint on the web page as the server may not > send you the same key it displays on the web page. > > Step 3: Sign the key > > bash$ gpg --sign-key <Key_ID> Ok. > > If you have multiple private keys, you can specify which of your private > keys to sign the other persons public key with like this: > > bash$ gpg --default-key <Key_to_use> --sign-key <Key_ID> > > Step 4: Return or Upload the signed key > > If you are working with an entity which does not want their key on a > public keyserver, you should at this point you should return their > signed key back to them by their method of choice - normally encrypted > email. You should not send a public key to a keyserver with out the > permission of the key's owner. Publicizing a public key slightly reduces > the security of a key pair, therefor it is considered rude to make a key > more public than its owner desires. > > Most likely you are working with a keyserver. If that is the case, you > can send the signed key back to the keyserver like this: > > bash$ gpg --keyserver <keyserver> --send-key <Key_ID> > > You should see a success message like this: > > gpg: success sending to `<keyserver>' (status=200) > Congratulations, the signature of the other entity's key is now complete > and your signature has been incorporated into their public key. A trust > path has been established. This looked different for me, $ gpg --send-key A9413B9F gpg: sending key A9413B9F to hkp server pgp.mit.edu $ No affirmative response, it just returned to the prompt. But the exit code was 0. $ echo $? 0 -Jamie [ not yet using gpg for mail ]

May 17, 2007

Follow-Up to Key Signing Party

by Eric Martin

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Thanks to everyone who showed up to tonight's key signing party. Now that we verified everybody had the correct key info and identification, we actually have to sign each other's keys. We are using the keyserver pgp.mit.edu. If that isn't your default, you can set it either in ~/.gnupg/gpg.conf or at the command line for each command by using the argument - --keyserver pgp.mit.edu Below is an excerpt from the gpg Key Signing Party HowTo that explains things in detail.(http://www.rubin.ch/pgp/kspa/gpg-party.en.html#ss3.8): 3.8 How to sign others' keys Step 1: Get a copy of the key Normally, you'll be working from a keyserver. However if you are signing the key that is not available on a keyserver, you can use simply import the key with gpg --import. If you are working with a keyserver, the following command will download the key from the keyserver into your public keyring. bash$ gpg --keyserver <keyserver> --recv-keys <Key_ID> If you get a read error, it means the keyserver is overloaded. Please, try again in a few seconds. Step 2: Fingerprint and Verify the key bash$ gpg --fingerprint <Key_ID> GPG will print out the fingerprint of the Key with <Key_ID > (the key you just downloaded). Check the fingerprint against the checklist that you where given at the party. Note: Don't check the fingerprint on your checklist against the fingerprint on the web page as the server may not send you the same key it displays on the web page. Step 3: Sign the key bash$ gpg --sign-key <Key_ID> If you have multiple private keys, you can specify which of your private keys to sign the other persons public key with like this: bash$ gpg --default-key <Key_to_use> --sign-key <Key_ID> Step 4: Return or Upload the signed key If you are working with an entity which does not want their key on a public keyserver, you should at this point you should return their signed key back to them by their method of choice - normally encrypted email. You should not send a public key to a keyserver with out the permission of the key's owner. Publicizing a public key slightly reduces the security of a key pair, therefor it is considered rude to make a key more public than its owner desires. Most likely you are working with a keyserver. If that is the case, you can send the signed key back to the keyserver like this: bash$ gpg --keyserver <keyserver> --send-key <Key_ID> You should see a success message like this: gpg: success sending to `<keyserver>' (status=200) Congratulations, the signature of the other entity's key is now complete and your signature has been incorporated into their public key. A trust path has been established. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGS+VsaiVxdKlBO58RAs3xAJ0W7SyjfbQtwHwDaHeWG5EgeWWXzgCfQ8pT W40gnhPVnkQ3u7E1jbXALvU= =GM/c -----END PGP SIGNATURE-----

May 17, 2007

Re: [Wlug] PGP Key Signing Party

by Gregory Avedissian

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Here's my fingerprint: pub 1024D/5DC682A4 2004-04-17 [expires: 2009-04-16] Key fingerprint = 4DF6 E8E1 5521 6ECC 7A3E E7F0 BF02 ADEA 5DC6 82A4 Greg Avedissian -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGS8i0vwKt6l3GgqQRAui5AJ4my59DCPMhLXnwIsZSLvvL3Qh62ACeMLt1 hJHV/oml3PBTo5117s9YXOA= =NO0Y -----END PGP SIGNATURE-----

May 17, 2007

Last-Minute Emergency, Unable to Attend

by Terry S

Hello, I had a phone call at 6:07 that required me to go out for a while, and did not have time to email. (I'm the one with the camera.) Hopefully, someone else just "happened" to have one, but I can take pictures at our next meeting if needed. How did the key-signing go? Terry

May 17, 2007

Re: [Wlug] large file performance on linux

by Jeff Moyer

==> On Wed, 16 May 2007 22:19:14 +0000, brad noyes <maitre(a)ccs.neu.edu> said: brad> All, brad> here's a summary of what i have tried so far. I have tried using the O_DIRECT brad> and O_SYNC flags with open(2) and i have been using a non-journalling brad> filesystem, ext2. None of these options have yielded any better performance at brad> the rates i'm looking for. brad> I have not tried AIO. AIO will allow you to drive your disk subsystem better than synchronous writes; I really think this would solve your problem. For an example of an AIO app, you can google for aio-stress.c. Or, send me some code and I'll help get you started. -Jeff

May 16, 2007