Date: Sat, 4 May 1996 10:25:08 +0200 (MET DST) From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-hackers@freebsd.org (FreeBSD hackers) Subject: Re: using DLT drive on FreeBSD Message-ID: <199605040825.KAA21347@uriah.heep.sax.de> In-Reply-To: <199605031838.UAA01522@yedi.iaf.nl> from Wilko Bulte at "May 3, 96 08:38:54 pm"
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As Wilko Bulte wrote: > > 64 KB, this is enforced by physio(9) [man page not yet written :)]. > > Many SCSI adapters do only allow for 16 scatter/gather segments, and > > in the worst case, you need one of them for each physical page. > > This would imply that non-SG adapters are unusable. Correct me if I'm > wrong but something like a Seagate ST-02 (junk, I know, but sea(4) > is available) does not do SG. ...nor does it do busmaster DMA. :) Busmaster DMA controllers are required to support scatter/gather, that's why some early revision AHA-154X-A's are unusable with FreeBSD (but this was a firmware revision problem, mine is working fine in the scratchbox). -- 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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