Re: How do disk writes work these days?
Re: How do disk writes work these days?
- Subject: Re: How do disk writes work these days?
- From: Pelle Johansson <email@hidden>
- Date: Tue, 30 Jul 2002 23:51:03 +0200
torsdagen den 25 juli 2002 kl 03.15 skrev Wade Tregaskis:
Is this still an efficient way of operating, in an increasingly linear
[e.
g. single-user] OS? I'm just thinking, if you could return from writes
faster, the calling process can keep doing other things. My thought is
that you could do this without breaking existing apps by performing any
error checking [i.e. quickly verifying there is free space, among other
things] immediately, returning fail if appropriate, or otherwise
returning no error. You could then worry about physically getting the
data to disk,
seeing as this is the most time intensive part...
Side note:
I was taught that if you know how large a file you want to write you
should use ftruncate() to set the file size before writing. That way the
OS can optimize the location of the file on the hard drive. I've noticed
Unix application are quite bad at doing this, so perhaps it doesn't
apply in some OSes.
--
Pelle Johansson
<email@hidden>
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