Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 03 Oct 1997 14:23:11 -0700
From:      Julian Elischer <julian@whistle.com>
To:        "Justin T. Gibbs" <gibbs@plutotech.com>
Cc:        Andrew Reilly <reilly@zeta.org.au>, freebsd-scsi@FreeBSD.ORG
Subject:   Re: New SCSI Framework Patches Available
Message-ID:  <3435623F.500F9F30@whistle.com>
References:  <199710031835.MAA04392@pluto.plutotech.com>

next in thread | previous in thread | raw e-mail | index | archive | help
Justin T. Gibbs wrote:
> 
> >On  2 Oct, Justin T. Gibbs wrote:
> >> Supported peripherals:
> >>
> >> Direct Access driver (da):
> >>      512 byte sectored disk drivers.  Support for other sector sizes is
> >>      planned, but further investigation on the "right" approach for this
> >>      is needed.  It probably belongs in the disk-slice code.
> >
> >Pardon for the unhelpful intrusion, but could someone please explain
> >the issue here?
> 
> The issue is that most of the system deals with devices in "DEV_BSIZE"
> chunks (512bytes).  In the past, each device driver has had to perform some
> amount of conversion if the device block size doesn't match that value.
> Performing the conversion to block sizes that are a power of 2 isn't hard,
> but in some cases, the block size is an "odd" value (Try writing audio
> tracks to a WORM for instance).  I'd like to deal with this issue cleanly
> and not require each and every device driver to handle this case on it's
> own.

Justin, I have new disk handling code that does this all cleanly.
I'll send you a copy as soon as I get the last killer bugs out of it.
in th emean-while don't spend too much time on this roblem as I'm
working on it.. It will fit into your stuff just fine I think.



> 
> So, the question is how to best handle the problem?  NetBSD has a few PRs
> in their gnats database that offer possible solutions.  I just haven't had
> time to really consider the problem in detail and come up with a clean
> approach.
> 
> >--
> >Andrew
> >
> >"The steady state of disks is full."
> >                               -- Ken Thompson
> 
> --
> Justin T. Gibbs
> ===========================================
>   FreeBSD: Turning PCs into workstations
> ===========================================



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3435623F.500F9F30>