Subject: Re: Supporting sector size != DEV_BSIZE -- patches
To: Manuel Bouyer , <>
From: Aaro J Koskinen <>
List: tech-kern
Date: 06/04/2002 00:53:57
On Mon, 3 Jun 2002, Manuel Bouyer wrote:

> On Mon, Jun 03, 2002 at 12:49:34PM -0700, Bill Studenmund wrote:
> > The main locus of the question is what have people been doing so far when
> > they use non-512-byte sectors? Yes, we have hacks for CDs. But what have
> > the MO folks been doing? Any MO users who can speak up?
> Well, all the MO I have have 512-byte blocks. I'm not sure there is
> that much MO drives with larger block size.

Check the data sheets of any MO drive! The sector size is media
specific. E.g. Sony's drives can be used with 512, 1024, 2048 and 4096
bytes/sector discs. Bigger capacity discs usually have non-512-byte
sectors. There may be also performance penalty with 512-byte sectors (I
think 512 bytes/sector is only supported for backwards compatibility
with legacy systems that do not support other sector sizes, and there's
some kind of emulation in drives).

Couple years ago I implemented MO support for a proprietary
NetBSD-based OS and took the approach described in PR #3791, probably
because I thought it was the quickest to do... Anyway, the used file
system was FAT32 and the discs were surprisingly compatible when taken
to a Windows system :-).


Aaro Koskinen
E-mail:            "I'm the ocean, I'm the giant undertow."