From owner-freebsd-scsi Sat Jun 29 07:15:18 1996 Return-Path: owner-freebsd-scsi Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id HAA04366 for freebsd-scsi-outgoing; Sat, 29 Jun 1996 07:15:18 -0700 (PDT) Received: from hda.com (ip23-max1-fitch.zipnet.net [199.232.245.23]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id HAA04356 for ; Sat, 29 Jun 1996 07:15:15 -0700 (PDT) Received: (from dufault@localhost) by hda.com (8.6.11/8.6.9) id KAA04079; Sat, 29 Jun 1996 10:11:30 -0400 From: Peter Dufault Message-Id: <199606291411.KAA04079@hda.com> Subject: Re: help writing a new SCSI device driver To: peter@taronga.com (Peter da Silva) Date: Sat, 29 Jun 1996 10:11:29 -0400 (EDT) Cc: scsi@FreeBSD.ORG In-Reply-To: <199606291232.HAA08596@bonkers.taronga.com> from "Peter da Silva" at Jun 29, 96 07:32:07 am Reply-to: hdalog@zipnet.net X-Mailer: ELM [version 2.4 PL24] Content-Type: text Sender: owner-freebsd-scsi@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk > > >All drivers should support disconnection/reselection to permit > >adequate bus utilization. The gains are great - you will tie up > >the bus during disk seeks, etc. if you don't support it. > > The biggest problems would be with tapes, I would imagine, during > rewinds and things like that. Some tape operations can take an > extraordinarily long time... Most of those have special commands that detach and finish up specifically to support brain dead hardware. That isn't to say we always use those commands, though. -- Peter Dufault Real-Time Machine Control and Simulation HD Associates, Inc. Voice: 508 433 6936 dufault@hda.com Fax: 508 433 5267