Re: Tweaking cron for use on laptops
In article [EMAIL PROTECTED], Bruce Perens [EMAIL PROTECTED] wrote: There are a few things that could be modified to facilitate spinning down the disk. Syslogd is compulsive about writing information to the disk right away just in case the system crashes. It could be given an option to buffer. I think it would be best if this option is implemented as a priority level at which syslogd would sync, for example `crit'. Messages logged at lower levels would be unlikely to be followed by a crash. -- Shields, CrossLink. -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Tweaking cron for use on laptops
Martin == Martin Gallant [EMAIL PROTECTED] writes: Martin I have been running Debian on my laptop for a few months Martin now. Good job guys. Unless I intentionally remove the Martin cron package form this machine, the hard drive will not Martin spin down. What would be nice is if I could configure Martin cron to only run say once per hour. That way I could take Martin advantage of the log cycling features of the system. Martin Reading through the vixie cron documentation and source, Martin there does not appear to be a straightforward way to do Martin this. Anyone thought about this? I've thought about that too. A friend of mine has a Thinkpad that can do a context dump to a disk partition, and start up right where you leave off. He told me that there's a desktop system available that can go to sleep like that also. I want one! I'd like to leave my machine on all the time. I've set my drives to spin down, using 'hdparm', but 'update' keeps them from stopping. There's a patch out, called 'atime' patch, if I recall, that is supposed to help alleviate this. It says it comes with a script that puts /dev/* in a ramdisk. I haven't explored it yet. But what about 'cron'? It ought to set an alarm that would wake up the computer just before a job is scheduled, run the job, and then go back to sleep. I suppose that a re-implementation of 'cron' and 'atrun' would be required to make this happen. Q: Does the real time clock have what would be required? (or a start on that?) How difficult would that be? Do those computer support something like this? They must, it seems such an obvious thing. Another thing I thought of is to install that screensaver hooks patch, and have the screensaver send a signal to a modified 'update' daemon. It could SIGUSER1 it, which would cause it to 'sync' and then toggle to OFF. When the screensaver deactivates, it would SIGUSER1 'update' again, and that would toggle update back on again. (Perhaps rather than ON/OFF, it would toggle between two update periods given on the commandline toupdate. A longer timeoutfor while screenblanker is active.) I tried to hack in a call to sync(); where the screen gets blanked in the kernel, naively. (Aiieeh!) Can't schedule during an interrupt. After I finish the bigred book, Beginning Linux Programming, I think I will get that Kernel Internals book and start on it. :-) There's a lot to learn. I'm not capable of coding any of that yet; I'm just a beginner. But I've thought about it some... :-) -- Participate in history! __ _Karl M. Hegbloom [EMAIL PROTECTED] / /(_)_ __ _ ___ __ http://www.inetarena.com/~karlheg / / | | '_ \| | | \ \/ / Portland, OR, USA / /__| | | | | |_| | Proudly running Linux 2.0.25 transname \/_|_| |_|\__,_/_/\_\ and Debian GNU public software! -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Re: Tweaking cron for use on laptops
Martin Unless I intentionally remove the Martin cron package form this machine, the hard drive will not Martin spin down. There are a few things that could be modified to facilitate spinning down the disk. Syslogd is compulsive about writing information to the disk right away just in case the system crashes. It could be given an option to buffer. Cron, as you say, is another candidate. Also, (on a much longer timeline) there are things that can be done in the filesystems. For example, the last-accessed time of a file doesn't have to be written immediately, especially if reading a block from the ram cache. Also, when a disk is spun down it should be put in the unmounted state - that is with all modifications committed to disk before it's spun down, and the mounted bit cleared in the superblock. The first write should set the mounted bit when it is spun back up. Martin Anyone thought about this? I doubt it would be much trouble to hack cron. Go for it. From: Karl M. Hegbloom [EMAIL PROTECTED] I've thought about that too. A friend of mine has a Thinkpad that can do a context dump to a disk partition, and start up right where you leave off. Linux can do that on the Thinkpad, and many other laptops, via APM. It's really a BIOS feature. My desktop will suspend, but the BIOS doesn't save RAM to disk so the power stays on. I've set my drives to spin down, using 'hdparm', but 'update' keeps them from stopping. There's a patch out, called 'atime' patch, if I recall, that is supposed to help alleviate this. It says it comes with a script that puts /dev/* in a ramdisk. I haven't explored it yet. That's the last-accessed time. I'd rather defer writing that information until I know the disk is spinning than put the devices in a RAM disk. But what about 'cron'? It ought to set an alarm that would wake up the computer just before a job is scheduled, run the job, and then go back to sleep. Take that 60-second alarm and make it 60 minutes. See what breaks. Fix it. Another thing I thought of is to install that screensaver hooks patch, and have the screensaver send a signal to a modified 'update' daemon. Most of what you need is already in the APM driver. I tried to hack in a call to sync(); where the screen gets blanked in the kernel, naively. (Aiieeh!) Can't schedule during an interrupt. But you can ask kerneld to perform a service for you, and then return from the interrupt. It will get there in a second or two. Bruce -- Bruce Perens K6BP [EMAIL PROTECTED] Finger [EMAIL PROTECTED] for PGP public key. PGP fingerprint = 88 6A 15 D0 65 D4 A3 A6 1F 89 6A 76 95 24 87 B3 -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
Tweaking cron for use on laptops
I have been running Debian on my laptop for a few months now. Good job guys. Unless I intentionally remove the cron package form this machine, the hard drive will not spin down. What would be nice is if I could configure cron to only run say once per hour. That way I could take advantage of the log cycling features of the system. Reading through the vixie cron documentation and source, there does not appear to be a straightforward way to do this. Anyone thought about this? -- Marty -- TO UNSUBSCRIBE FROM THIS MAILING LIST: e-mail the word unsubscribe to [EMAIL PROTECTED] . Trouble? e-mail to [EMAIL PROTECTED]
