From owner-freebsd-scsi Fri May 2 13:20:51 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id NAA20635 for freebsd-scsi-outgoing; Fri, 2 May 1997 13:20:51 -0700 (PDT) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by hub.freebsd.org (8.8.5/8.8.5) with SMTP id NAA20628 for ; Fri, 2 May 1997 13:20:48 -0700 (PDT) Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id WAA25488 for freeBSD-scsi@FreeBSD.ORG; Fri, 2 May 1997 22:20:40 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.8.5/8.8.5) id WAA00534; Fri, 2 May 1997 22:10:44 +0200 (MET DST) Message-ID: <19970502221044.EH53977@uriah.heep.sax.de> Date: Fri, 2 May 1997 22:10:44 +0200 From: j@uriah.heep.sax.de (J Wunsch) To: freeBSD-scsi@FreeBSD.ORG Subject: Re: cvs commit: src/sys/scsi sd.c References: <199705012023.GAA24197@godzilla.zeta.org.au> <199705012119.PAA20788@pluto.plutotech.com> X-Mailer: Mutt 0.60_p2-3,5,8-9 Mime-Version: 1.0 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: <199705012119.PAA20788@pluto.plutotech.com>; from Justin T. Gibbs on May 1, 1997 16:17:24 -0600 Sender: owner-freebsd-scsi@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk As Justin T. Gibbs wrote: > 3) What features do we want to support? Do we want to support the ability > to 'dd' an image from a 512byte sectored device to a 1k sectored device > and have it work? No. Raw device access is restricted to the physical block size. This is already enforced in the floppy driver, which is capable of handling 1 KB physical sectors. This is, for example, enforced in the worm(4) driver when writing audio frames: the blocksize must be a multiple of 2352 bytes. This will be enforced in a CD-DA reading mode of the cd(4) driver, if i ever get around to implement it. :) > 4) If we want to have partitions with the only constraint being that they > begin and end on a sector boundary, what else in the system needs to change > to allow this? How does this affect 2 and 3? IIRC, the biggest problem was the UFS filesystem code assuming everything can be aligned to DEV_BSIZE. -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)