Re: Lock up's on USB transfer

[Rhialto <rhialto%falu.nl@localhost>]

On Thu 11 Sep 2008 at 09:53:33 -0600, Swift Griggs wrote:
> Not to be negative, but I've also had the same experience. USB+msdos/vfat 
> == crashes & fs-lockouts. ie.. Either the storage locks up or the machine 
> does. I've also noticed that USB+msdos_fs is orders of magnitude slower 
> than ffs/lfs/ext2 on the same unit. I know it's an ineffecient FS, but not 
> 200%+ slower.

Well, there was a big efficiency problem that I fixed but it returned in
4.0.

When appending to a file. the FAT would be re-read every time the file
was extended by a cluster. I fixed it by doing some extra caching of
data from the FAT, but access patterns apparently changed enough in 4.0
so that that doesn't work anymore.  See
http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=38095 and
http://www.netbsd.org/cgi-bin/query-pr-single.pl?number=34583

> Swift Griggs -- <swift.griggs%coloradovnet.com@localhost>
-Olaf.
-- 
___ Olaf 'Rhialto' Seibert      -- You author it, and I'll reader it.
\X/ rhialto/at/xs4all.nl        -- Cetero censeo "authored" delendum esse.