On 27/10/2007, elroy <elroy(a)ihug.co.nz> wrote:
c) Can anyone explain in nice laymans terms the correct use of the 'Alt + SysReq' and 'Alt + S' and 'Alt + U' and 'Alt + B' key sequence (I used this to (I think) tell the machine to safely shut down).
Alt-SysReq gets you a minimal interaction with the kernel when the userspace of the machine has gone bye-bye for whatever reason (fork-bomb, swapping madly, etc). The three commands you mention above are: S - Sync disk, flushes all disk buffers so all pending writes hit the disk surface. U - remounts all file systems read-only to prevent further modifications B - Reboot It's basically a safer way of forcefully rebooting the machine than just hitting the reset button as you're at least giving the disks a reasonable chance to get it sync and cleanly unmounted before you restart. You can also use 'e' and 'i' before the s-u-b sequence to send SIGTERM and SIGKILL to all processes to give them a chance to clean-up nicely first too. -- Matt Brown matt(a)mattb.net.nz Mob +353 86 608 7117 www.mattb.net.nz