Thus spake World Scientific Publishing US Office:
> 
> At 9:15 PM 7/16/96, Dan.McMahill@sciatl.com wrote:
> >
> >I have been simply using "halt".  This syncs disks and turns
> >my IIci off.  Am I doing something even worse?  (Sorry for the
> >simple question, but it seems that there are others as confused
> >as I).
> >
>         What does "syncs disks" mean?
>         BTW I was asking if there is any difference between
>         "shutdown -h now" and "halt", and I have heard nothing
>         back yet.

First, sync'ing disks refers to synchronizing in-core filesystem status with
actual states on the filesystem.  What that means, simplified, is that a un*x
system keeps an internal cache (bad choice of phrasing, I know) of the state
of certain files.  When you save a file, it may not actually be written to the
filesystem until a convenient time, though things will always function
transparently.  I fyou simply powerdown, this descripency between physical and
in-core status can cause strange and very unfortunate filesystem damage.

The shutdown script actually sends first SIGHUPs and then SIGKILs (consulting
memory here) to running processes which gives them a chance to quit in their
specified ways gracefully.  halt has a bad habit of just ridding the system
oof everyting running with no regard to manners.  Hence, "shutdown -h now"
tends to be my answer to powerdown needs.

Gene


_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/
/_/  Gene E. Skonicki    _/_/ Phone: (847) 266-8770                      _/_/
_/   gene@imsa.edu      _/_/ Of course I'm sane, the voices tell me so. _/_/
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