Re: [lopsa-tech] C coding
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/8/10 11:07 , Andrew Hume wrote: bill said (elided to preserve what sanity might be left in readers) My headache just got a *lot* worse - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkyv5SIACgkQIn7hlCsL25VATQCgpUqdLcJqokdBoicasP3o1II/ KB8An2LT3WepS3nOl+ifMdrccR7K7htz =+X/3 -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] C coding
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/8/10 13:48 , Michael Tiernan wrote: - Tom Limoncelli t...@whatexit.org wrote: I see this in code now and then: 116-1 Being just a system geek and not a professional programmer, I don't understand why one would use that notation instead of the more obvious variations of 0x8000? I understand that the compiler, at compile time (not run time) will figure out that the programmer meant 0x8000 from that piece of code so the end result is the same but it seems that for documentation purposes it'd be more obvious to do it the other way. Am I missing something? I see it as a matter of self-documentation; 0x8000 suggests a magic number of some kind, which is probably related to bits or to hardware control, whereas 1(mumble) explicitly says this is a bit. (The former might be a bit *mask*, or not linked to particular bits at all, for example a value written to a control register where the register isn't documented at the bit level but only the acceptable values.) Also, the 1n syntax helps when you are coding to a specification which describes things in terms of bit numbers (e.g. bit 0 controls the transmit register). - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkyv52wACgkQIn7hlCsL25WN4wCghwyD0hLGLaV8P4UDUXtOj1S8 KCsAoK4S6h/DBs4G7pp/WDRKkds844wn =/va/ -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Build Your Own Skype
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 9/29/10 00:04 , Brad Knowles wrote: My experience with Skype for audio chat is that it's actually not that good For what it's worth, I listen to a lot of podcasts where one or more parties are Skyped in... and they're constantly having problems with audio quality, dropouts, dropped connections (and occasional inability to reconnect), etc. Doesn't inspire much in the way of confidence. - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkyjf7QACgkQIn7hlCsL25Xe8wCcCCpBaBPKoohn8VGBlePbBkRn eZ8AnjemeFH/67aK3gTdMy1mTCNLaDmk =9fBU -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Disingenuous side-swipes
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 9/26/10 22:58 , Edward Ned Harvey wrote: From: Brad Knowles [mailto:b...@shub-internet.org] I didn't claim that FaceTime was there yet. But if you want to criticize a product or a service, you should actually take the time to learn one iota or two about it, before you start bashing it. Geez, between this and the wave comment, I don't know where this is coming from. I'm not bashing anything. Wave and facetime are both cool in their Where this is coming from is the way you made your comments; both came across as confrontational, i.e. as attacks. If that's not what you intended, you may want to reconsider how you make your points. - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkygCxUACgkQIn7hlCsL25XJxQCglhyWnZbXykTm1iCpshwvGFmE x28An1f7Dbt0dltoJadMXhGEUrfDoa4a =xFtA -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] whole disk encryption
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 8/24/10 20:34 , Paul Graydon wrote: On 08/24/2010 02:25 PM, Doug Hughes wrote: You're right. I confused secure erasing (which no longer requires many passes, even though it remains part of the common cargo-cult lore), with That one whizzed past my head with an audible whooshing sound. Since when does secure erasing no longer require multiple passes? I think that's actually slightly backwards: with current drive densities, multiple passes don't change significantly more magnetic domains than single passes (if they did then they would wipe out neighboring bits). - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkx1RBQACgkQIn7hlCsL25VbsQCeL7wZjj17aY9A4eVvsvjxhmAt IDEAoNZjbZm1lEPeBnOPicLU180CxnZ7 =egNP -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Http Health Checks
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 8/2/10 21:25 , Derek J. Balling wrote: Yes it means twice as much SNMP traffic for a bunch of metrics that are in the join-set of trend and monitor/alert, but it's well worth it, in my opinion. Caching proxy? - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkxXeNIACgkQIn7hlCsL25XWbwCeK9LbfOdAvudBJppOsYr5HC4u s2MAn0X2wHsM1g+Po/8XZDYAo6zxlyli =10z9 -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] storing fsfs-formatted svn repos atop nfs: good bad or ugly?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 7/2/10 09:06 , Nick Silkey wrote: It appears fsfs-formatted svn repos are indeed NFS safe, but I wanted to ask the audience. Anyone with experience doing this (good, bad, otherwise), let me know. I welcome responses like 'yeah, it can be done. i did it, but the performance stunk!' ... not just the simple 'yes' or 'no'. I haven't tried it with NFS, but it works fine in AFS read/write volumes. (fsfs was specifically designed to work in AFS/NFS; early performance was weak but it's improved with every release.) - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkwuCswACgkQIn7hlCsL25XpXgCgpuPVEzfaW8TddjU50QICa+gn wC8AnjtHH7Ys3lHp4jYnvi46xkHUQieJ =1B/F -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] CentOS 5.4 binaries different though package version identical.
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 6/30/10 21:07 , Aleksey Tsalolikhin wrote: Same thing: same file size, same datestamp, same package version; but the binary is actually different; yet rpm -V does not complain. Why? Because prelinking changes the file in different ways on different systems. And, as I read this, your verify failure *and* the slowness are tied to that message you got from rpm -V: it's not rpm saying that, but the prelink command it runs to un-prelink for verification, telling you that the prelink data for the one that isn't acting right *is wrong*. The slowness would then be because at every symbol lookup it's hitting the prelink failure and then looking up the symbol the hard way, one at a time. (That is, working prelink is an optimization, but *failed* prelink is a pessimization, compared to non-prelinking. System V R2/3 and Mac OS X prelinking have the same optimization/pessimization issues, BTW.) The likely fix here is to read up on the prelink command and see how to fix or remove the broken prelink information from /sbin/mkfs.ext3. - -- brandon s. allbery [linux,solaris,freebsd,perl] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon university KF8NH -BEGIN PGP SIGNATURE- Version: GnuPG v2.0.10 (Darwin) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkwsPgUACgkQIn7hlCsL25XvVgCgw4eFwR08T+pko8/tATmQyLgB 7dAAoL6BK6qQO/NYITD1sC0xYVk0d9yD =YZfL -END PGP SIGNATURE- ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] nix - build system
On Mar 17, 2010, at 16:41 , Doug Hughes wrote: Does anybody here use Nix just for the dependency analysis and build system that it has? That parts seems extractable in a way similar to the way that modules is used, but I wonder if anybody is doing that? Not yet; it's on my list of things to look into, though. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Force session initialization for SSH
On Feb 25, 2010, at 10:51 , Mark McCullough wrote: Since the user environment is not utilized, but TIM relies on that environment, the product is failing to operate correctly. User .profiles are ignored, /etc/profile is ignored, etc. We've considered the sshd_config PermitUserEnvironment setting, but that would open up too nasty a security hole since I can't lock it to a single user. Does anyone have any suggestions on how to address this problem? Use ForceCommand to specify a script which sets the environment up? (btw, you should be able to PermitUserEnvironment in a Match User block, same way you'd use ForceCommand,but ForceCommand would give you more control) -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Email naming convention
On Oct 23, 2009, at 23:29 , Joseph S D Yao wrote: Or get a separate calendar. I mean, who first thought to put a calendar into a MAIL program, of all things? Anyone who schedules meetings via email. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] SSD's - really any better performance?
On Sep 16, 2009, at 09:11 , Yves Dorfsman wrote: Tracy Reed wrote: Also consider that when a SATA drive dies your data is gone. When an SSD drive dies as a result of too many writes it just goes read-only. Vastly different failure modes which you may want to consider if weighing MTBF. I know which one I prefer. Would you trust a drive that fails on write ? If it reports an error and falls back to read-only, sure; it is, as noted, far more recoverable. Beyond that, well, that's what RAID is for. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] shared network disks - vs gfs - vs distributed filesystem - vs ...
On Jul 2, 2009, at 11:53 , Atom Powers wrote: I didn't see AFS mentioned yet. My, admittedly incomplete, understanding of afs is that it provides a single namespace (directory tree) to all clients but the files themselves may be stored on a local or remote server; a bit like Microsoft DFS. Standard AFS doesn't quite work like that; even if you're running on the fileserver (a bad idea) you're still going through the protocol (AFS filesystems are not directly accessible via *nix APIs) and the local disk cache, and you want anything like local speeds you need a cache large enough to hold the entire working set. There *is* an experimental hostafs that enables individual workstations to share out their normal disk space in the way you're talking about, but I gather the code doesn't work with current versions of AFS. You could post a query to openafs-i...@openafs.org if you're desperate. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] patch management for MacOSX
On Jun 23, 2009, at 17:16 , unix_fan wrote: Two generic scenarios come to my MacOSX rookie mind: 1. Write ssh queries that look for OS versions and patch status, or 2. Utilize a CM tool like puppet/bcfg2/lfcg/fill in your fave. Apple's blessed solution seems to be radmind. sw_vers gives you the OS revision and kernel build level, but no patch information. softwareupdate lets you see what updates are available. Anything else I think ends up with you poking around under /Library/ Receipts/boms. The good news is that security updates are easy to track there: mress:4819 Z$ ls /Library/Receipts/boms/*update* /Library/Receipts/boms/com.apple.pkg.update.os.10.5.3.bom /Library/Receipts/boms/com.apple.pkg.update.os.10.5.4.bom /Library/Receipts/boms/com.apple.pkg.update.os.10.5.5.bom /Library/Receipts/boms/com.apple.pkg.update.os.10.5.6.combo.bom /Library/Receipts/boms/com.apple.pkg.update.os.10.5.7.bom /Library/Receipts/boms/com.apple.pkg.update.security.2008.002.bom /Library/Receipts/boms/com.apple.pkg.update.security.2008.005.bom /Library/Receipts/boms/com.apple.pkg.update.security.2008.007.bom /Library/Receipts/boms/com.apple.pkg.update.security.2009.001.bom (The bad news, as shown above, is that you have to intuit that 2008.005 also includes 2008.003 and 2008.004.) What do people who manage groups of MacOSX desktop machines actually use? To bound the exercise, let's just call patch management the following task. At present we're doing them all manually. I'd love to change this, but a not-insignificant number of them are laptops that might or might not be on our network at any given time. (Windows laptops have always given us problems as well.) -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Tapes, not backup...
On 2009 Feb 12, at 14:22, Doug Hughes wrote: Tim Kirby wrote: Thanks for the comments so far. As I noted (or tried to) this is a second hand request and is specifically *not* backup - it's tape library management apps for a linux box with an attached library for simple tape archival use. We're talking about people who want to put a bunch of data on a tape that may or may not be needed in 5 years time. Perhaps 10. The archival bit is relevant; it's not a backup. ... Have you considered 2 tapes? Dropping a tape and having it damaged (or If you'd quoted a bit farther you would have found: There isn't a remote operator to phone up and ask to diddle with the tape library - Joe wants to do something that results in the data he points at being written to a tape (actually probably two), -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Best Unix Backup Rotation strategies?
On 2009 Feb 5, at 13:40, Elizabeth Schwartz wrote: Part of what set this off, BTW, is that I lost one of my big RAID's, and did a 600GB restore. That took about a day and a half. Then, the next five days in a row we got socked with 600GB of data backup charges, as that 600GB got backed onto level 5,4,3,2,1 tapes in that order... The more I think about that, the more I suspect the backup scheme is designed to maximize revenue rather than pursue any theory about data retention. If so, you may not be able to get changes made at all. (Although I suppose it could be a we do it this way by default, if they catch on, let them spec their preferred sequence maximizing income from the naïve.) -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [openafs,heimdal,too many hats] allb...@ece.cmu.edu electrical and computer engineering, carnegie mellon universityKF8NH PGP.sig Description: This is a digitally signed message part ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
Re: [lopsa-tech] Personal use of company IT equipment
On 2008 Nov 10, at 18:36, [EMAIL PROTECTED] wrote: legitmate reasons to care are (in my opinion): 1. no space to install stuff that they need 2. you are backing up more stuff and it's costing you. 3. you are worried that they have illegal things on there and that you will get in trouble over it. 4. The IRS is making noises over personal use of company-owned resources (we got dinged over cellphones by this; we no longer get cellphones as a result). You need legal and HR involved in this case. -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] [EMAIL PROTECTED] system administrator [openafs,heimdal,too many hats] [EMAIL PROTECTED] electrical and computer engineering, carnegie mellon universityKF8NH ___ Tech mailing list Tech@lopsa.org http://lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
