Date: Thu, 30 Jan 1997 22:56:20 +0100 From: j@uriah.heep.sax.de (J Wunsch) To: freebsd-scsi@freebsd.org Subject: Re: XXXminpys question Message-ID: <Mutt.19970130225620.j@uriah.heep.sax.de> In-Reply-To: <199701301110.GAA10436@hda.hda.com>; from Peter Dufault on Jan 30, 1997 06:10:02 -0500 References: <Mutt.19970130102014.j@uriah.heep.sax.de> <199701301110.GAA10436@hda.hda.com>
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As Peter Dufault wrote: > > The adapters _are_ the reason for a minphys, so there should only be > > one at all. We should probably add it to the cdevsw entries. It can > > default to minphys (64 KB). > > You still want an overall system minphys to prevent a rogue driver / rogue > dd from crashing the system. It is the maximum amount you're willing to > guarantee to lock down for a raw transfer. I remember that David Greenman once said that the main reason for the existing minphys was the limitation of the SCSI adapters. Maybe there should be another minphys, but more something like 1 MB or larger then. The existing 64 KB limitation is something seriously small. Think of SGI's (stupid) habit of writing 256 KB blocked tapes, or of something like a WRITE BUFFER command to download firmware where the device will only accept the entire buffer at once (supposedly since it tries to compute a checksum on the fly). I think my Tandberg tape belongs to this group. It's annoying to boot a DOS floppy just for a SCSI firmware upgrade only. -- 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. ;-)
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