Re: fadvise syscall?

From: Anton Altaparmakov (aia21@cam.ac.uk)
Date: Sun Mar 17 2002 - 12:14:20 EST


At 15:13 17/03/02, Ken Hirsch wrote:
>There is a posix_fadvise() syscall in the POSIX Advanced Realtime
>specification
>http://www.opengroup.org/onlinepubs/007904975/functions/posix_fadvise.html

Posix or not I still don't see why one would want that. You know what you
are going to be using a file for at open time and you are not going to be
changing your mind later. If you can show me a single _real_world_ example
where one would genuinely want to change from one access pattern to another
without closing/reopening a particular file I would agree that fadvise is a
good idea but otherwise I think open(2) is the superior approach.

In addition, open(2) allows you to do cool things like O_TEMP which could
create a file that would never get written to disk at all and on close
would just disappear again (just an idea, I can see good uses for such
things, although in a way we already have simillar semantics when one
creates such files on a tmpfs mount).

Best regards,
Anton

>I don't know if this has been mentioned on linux-kernel before, but in
>January, the Open Group, in cooperation with IEEE, added the POSIX
>functionality to their specification and made it available online for free.
>It's at
>http://www.opengroup.org/onlinepubs/007904975/toc.htm
>
>There are some useful tables at
>http://www.unix-systems.org/version3/online.html and they ask that you
>register there so that they know how many people are using the
>specification.
>
>They don't have a downloadable version of this specification, but they do
>for the previous versions:
>http://www.opengroup.org/onlinepubs/007908799/download/
>
>Ken Hirsch
>
>
>
>-
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-- 
   "I've not lost my mind. It's backed up on tape somewhere." - Unknown
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Linux NTFS Maintainer / WWW: http://linux-ntfs.sf.net/
ICQ: 8561279 / WWW: http://www-stu.christs.cam.ac.uk/~aia21/

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