What you can do to help:
If you can't connect to your favourite computer:
Until recently, shutting down Linux computers was not encouraged, for two reasons. First, a remote user might be using the PC or running a job on it when it was shut down, and second, they might wish to log in while the computer was off and find themselves unable to do so. However, there are now solutions to these problems - the ``safeshutdown'' command will check whether a Statslab machine is idle before powering it down, and the ``wake'' command can be run on one Statslab machine to activate another one.
Therefore I have configured the Linux computers to shut themselves down at 22:00 every night if they are idle. At present machines in offices will turn themselves on automatically at 08:00 every morning unless the user has requested otherwise, but this may change. If you would like the automatic morning wakeup disabled for your machine then please tell me. (Of course this means that if something goes wrong with your machine I'll have no way of knowing.)
Those of you who use Linux machines outside the Statslab may find it useful to know more about the checks which are automatically run by safeshutdown and safereboot. To see whether a computer is in use, type ``w'' into a terminal window. The output will look like this:
10:30:57 up 14 days, 45 min, 3 users, load average: 0.02, 0.10, 0.08 USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT eva :0 - 08:59 ?xdm? 48:42 0.16s -/bin/tcsh -c / eva pts/2 :0.0 08:59 0.00s 0.07s 0.01s w eva pts/1 :0.0 08:59 21:47 0.54s 0.02s ssh ermyers@chi
The ``load average'' mentioned in the first line is a measure of how heavily loaded the computer is. (The three numbers are the load averages for the last 1, 5, and 15 minutes.) If any of these numbers is over 0.5, someone is probably running a long job on your computer, and it should be left on.
The remaining lines indicate who is logged onto the computer, where they are logged on from, when they logged on, and what they are doing. They contain a lot of information in a very small space, but for the purpose of determining whether the computer is in use, you need only look at the first column. If you see any login name other than your own, that person is using the computer, and it must be left on.
In the example above, the computer is unloaded and no-one but me is using it, so I could safely shut it down to save power. The easiest way to do this is to select ``Shut Down'' from the System menu. You can also type ``poweroff''.
If you have a recurring problem with ``your'' computer being down when you want to use it, there are several options. You can leave yourself logged in at all times so that it never shuts down automatically. You can ask me to turn on the 8:00 am wakeup, which may have been disabled at the request of the previous user of your office. Technically savvy users can run their own cron jobs on sirtommy to wake up their computer at a time which suits them.
If you want to wake up some computers in order to run a number-crunching job, then this list of Statslab computers and their ages may be of interest to you.