Subject: Re: msdosfs performance problem
To: Jaromir Dolecek <jdolecek@NetBSD.org>
From: David Laight <email@example.com>
Date: 11/27/2005 12:39:33
On Sun, Nov 27, 2005 at 01:16:58PM +0100, Jaromir Dolecek wrote:
> File blocks are chained by a pointer from the previous file
> block, so if you need to extend the file, you need to walk
> the whole file chain (i.e. read all intermediate file blocks)
> in order to find last block.
> However, this doesn't quite explain the number of reads. While
> the file blocks must be read the first time a file is extended,
> no more reads should be necessary when the file is extended
> again (the data should be in buffer cache).
You only need to read the FAT for that, not the file.
David Laight: firstname.lastname@example.org