I noticed someone a little while back on the freebsd list posted 
	a whole lot of patches for using sector sizes other than 512
	(I think)...

	My ignorance as to the situation with NetBSD is breathtaking :)

		David/abs

 D.K.Brownlee@city.ac.uk (MIME) +44 171 477 8186  {post,host}master  (abs)
Network Analyst, UCS, City University, Northampton Square, London EC1V 0HB.
        <<< Monochrome - Largest UK Internet BBS - telnet mono.org >>>
>=- Microsoft: Abort and Retry Cancel -or- NetBSD: http://www.netbsd.org -=<

On Wed, 20 Sep 1995, Erik E. Fair wrote:

> At 22:04 9/19/95, matthew green wrote:
> 
> >besides format, and libkvm programs, what else is there that doesn't
> >work ?  who needs format, anyway ?  disklabel(8) works for us now.
> 
> My memory tells me that one of the wins in 4.1 BSD UNIX over its
> predecessors was that they didn't just double the block size from 512 to
> 1024 - they actually formatted the disks in 1024 bytes/sector so that you
> could get those big blocks in just one go-round with the disks and driver.
> This lead later to FFS.
> 
> Somewhat later on, I was writing my first device driver suite for a
> commercial company: an ST-506/412 5.25" disk driver (UNIX), plus standalone
> driver for our boot PROMs, plus a standalone formatter. This stuff was
> written for 7th Edition, and then later converted (trivally) to System III,
> and System V. I invented my own disk label and badsector forwarding because
> there weren't any standards for that kind of stuff, and you needed to do it
> on a per-controller basis anyway (our systems eventually knew how to speak
> SA4000, ST-506/412, SMD, and XSMD (Fujitsu Eagle)). As an additional
> historical note, ST-506/412 grew up and became ESDI, more or less, driven
> principally by Maxtor's insatiable desire to build bigger and bigger disks.
> 
> Among the other features of ST-506/412 was that you could format the drives
> at anything from 128 bytes/sector to (I think) 4096 bytes/sector (with
> correspondingly fewer sectors per track). Interestingly, according to some
> trivial calculations you can make given the documentation, you got the
> highest capacity out of an ST-506/412 drive if you formatted at 1024
> bytes/sector - that's what made more efficient use of the actual number of
> bytes per track on the typical drives of the day (mostly MFM, though RLL
> was just beginning to show up, too). Unfortunately, we were always stuck
> with UNIX's assumption (mostly in the bio.c code) about 512 bytes/sector (I
> bet it's DEC's fault), and so we never tried anything different than that.
> 
> SCSI came after I did all this work (it was called SASI in those days, and
> there never was a controller for SASI that we thought we could use on the
> bus our system was based on (would you believe, S-100? (IEEE-696)), so I'm
> not sure if the same things are true of SCSI. Would someone with more
> experience than I care to comment about formatting SCSI at other than 512
> bytes/sector?
> 
> Erik Fair
> 
>