Re: /var/tmp vs. /tmp

[Gerhard Niklasch <nikl@mathematik.tu-muenchen.de>]

In response to:
> Message-ID: <20010525100924.A16071@lactaire.ens.fr>
> Date: Fri, 25 May 2001 10:09:24 +0200
> From: Louis Granboulan <Louis.Granboulan@ens.fr>
> To: PARI lovers <pari-dev@list.cr.yp.to>
> References: <200105240125.DAA12431@sunscheurle3.mathematik.tu-muenchen.de>
> 
> Gerhard Niklasch answered on pari-users mailing list :
> > > When UNIX PARI does MPQS, it uses several temporary files in /var/tmp.
> > 
> > Or wherever you point GPTMPDIR in the environment.
> 
> I am wondering why /var/tmp is preferred to /tmp

Dark history... the default goes back to the days when I had /tmp
on my Linux 1.2.8 box in the tiny root filesystem, and oodles of
space in /var where /var/tmp was living, and both were equally
performant.

> Usually, /tmp is better for such temporary files.
> /var/tmp is needed for files to be preserved after
> reboots, and that constraint is useless for MPQS.

At present (until one day we have a way of recovering from a
checkpoint state)...

> On some OS (Solaris) /tmp is much faster than /var/tmp,
> even when written to disk.

Absolutely.  By all means, if you have a large and fast /tmp,
override the default.  Perhaps the default should be changed
nowadays.  (but certainly not in 2.1.x!  changing user interface
behaviour is usually a Bad Idea(tm)...).

Cheers, Gerhard