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| -rw-r--r-- | doc/info/chap/overview.texinfo | 47 |
1 files changed, 46 insertions, 1 deletions
diff --git a/doc/info/chap/overview.texinfo b/doc/info/chap/overview.texinfo index 6bfb153..d2d8252 100644 --- a/doc/info/chap/overview.texinfo +++ b/doc/info/chap/overview.texinfo @@ -1,5 +1,50 @@ @node Overview @chapter Overview -TODO TODO TODO TODO TODO TODO TODO TODO +@command{sat} is a simple alternative to @command{at}. +It implements the basic features of at @command{at} +in a sane less harmful way. It is hence by itself +incompatible with @command{at}. + +@command{sat} is used to queue jobs for later execution. +It is daemon-based, the deamon being @command{satd}, and +using @command{satq}, @command{satrm}, and @command{satr} +you can list queued jobs, remove queued jobs, and run +queued jobs early, respectively. @command{satd} is launched +automatically and exits automatically when it has nothing +more to do. + +If you are using @command{autohaltd}, you should set up +hooks for @command{sat} that pauses @command{autohaltd} +using @code{SIGSTOP} (and resume with @code{SIGCONT}) +when there are queued jobs. This would prevent +@command{autohaltd} from shutting down the machine +while there are queued jobs but no logins. @command{sat} +cannot stop @command{autohaltd} by adding login entries, +because @command{autohaltd} will only recognise them if +they are in fact true logins. + +@command{sat} was written because @command{at} is far +too complex and has a lot of issues. @command{at} +sanitises the environment, @command{sat} does not do +this because you can do this with @command{env}, and +you will not lose environment variable that you my +want to keep, which sometimes happens with @command{at}. +@command{at} also do mailing, @command{sat} instead +lets you implement this with hooks, so that it is +less complex and less restrictive. @command{at} does +system load analysis, which @command{sat} does not, +instead you can use an external program for this. +@command{sat} also only has one queue, because you +do not need more than one queue, queues can easily +be emulated. Finally, the authors of @command{at} had +the brave idea to do natural language parsing, +@footnote{Good luck getting that to work properly +for even just English!} @command{sat} does however +do trivial parsing. + +Some think that @command{at} shall be merge into +@command{cron}. The authors of @command{sat} does +not think so because it is two wilding different +kind of job scheduling. |