Date: Tue, 17 Nov 1998 12:22:53 +0100 From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-scsi@FreeBSD.ORG Subject: Re: 520byte sector size Message-ID: <19981117122253.18551@uriah.heep.sax.de> In-Reply-To: <199811162152.NAA14263@math.berkeley.edu>; from Dan Strick on Mon, Nov 16, 1998 at 01:52:48PM -0800 References: <199811162152.NAA14263@math.berkeley.edu>
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As Dan Strick wrote: > I believe the correct method is to change the "data bytes per phys sector" > parameter (bytes 12 and 13, big endian) on the "format parameter page" > (page code 3) immediately before reformatting. That's not completely true. The SCSI standard isn't very specific in this, and a number of comments and notes that are located in the description of block descriptors imply that you can use them to alter the (logical) block size possibly requiring a future FORMAT UNIT command to get into effect. Physical sectors aren't necessarily the same as logical blocks, and you're only actually interested in logical blocks (this is what the READ and WRITE commands handle). So the outcome is, both ways (block size in the block descriptor, and physical sector size in the medium format page) cannot clearly be dismissed as ``not supported by the standard'' and are apparently allowed. > I have a program that lets you manually edit individual fields of > mode pages symbolically. The command sequence would go something > like this: Hmm, something like scsi -e -m <something> (old SCSI system), or camcontrol -e -m <something> (CAM system)? FreeBSD used to have it for years... -- 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. ;-) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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