*BSD News Article 80946


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From: Frederic.Marand@osinet.fr (Frederic MARAND)
Newsgroups: comp.os.linux.development.system,comp.unix.bsd.freebsd.misc
Subject: Re: Linux vs FreeBSD disk io performance
Date: Thu, 17 Oct 1996 06:50:59 GMT
Organization: Groupe SEDI / Agorus SA / OSI SARL
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Ivar Hosteng <ivarh@romulus.ihosteng.priv.no> wrote:
>Can someone explain this different behaviour?

There's one silly thing I noticed years ago on HP-UX : the code for
the /dev/null driver is less efficient than the one for disk I/O. 

Unbelievable as it seemed to us at the time, we got much better
throughput for disk accesses on copies to disk than we got on the same
copies to /dev/null. Not having access to the null driver code, we
could not see why this happened, but it was really surprising since
this does not seem to be a driver with much code in it...

Granted, that was years ago, and on HP-UX, not Linux or FreeBSD. But
maybe the difference here is also on the /dev/null side, not the disk
side.

Frederic G. MARAND
Agorus SA / OSI SARL
Frederic.Marand@osinet.fr