From owner-freebsd-current Sat Oct 3 20:05:39 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id UAA22058 for freebsd-current-outgoing; Sat, 3 Oct 1998 20:05:39 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from smtp01.primenet.com (smtp01.primenet.com [206.165.6.131]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id UAA22050 for ; Sat, 3 Oct 1998 20:05:29 -0700 (PDT) (envelope-from tlambert@usr06.primenet.com) Received: (from daemon@localhost) by smtp01.primenet.com (8.8.8/8.8.8) id UAA17720; Sat, 3 Oct 1998 20:05:09 -0700 (MST) Received: from usr06.primenet.com(206.165.6.206) via SMTP by smtp01.primenet.com, id smtpd017696; Sat Oct 3 20:05:01 1998 Received: (from tlambert@localhost) by usr06.primenet.com (8.8.5/8.8.5) id UAA21515; Sat, 3 Oct 1998 20:04:58 -0700 (MST) From: Terry Lambert Message-Id: <199810040304.UAA21515@usr06.primenet.com> Subject: Re: Long SCSI probes (was Re: Long IDE probes?) To: arg@arg1.demon.co.uk (Andrew Gordon) Date: Sun, 4 Oct 1998 03:04:58 +0000 (GMT) Cc: karl@Denninger.Net, current@FreeBSD.ORG In-Reply-To: from "Andrew Gordon" at Sep 30, 98 11:20:33 pm X-Mailer: ELM [version 2.4 PL25] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > Note that the SCSI bus is reset before probing; SCSI devices vary wildly > in their reaction to this. I have a tape drive that, if there is a tape > in the slot, engages in considerable tape movement (presumably to detect > the tape format/capacity) - this device requires (pre-CAM) SCSI_DELAY=23 > to survive rebooting with a tape loaded. Even disc drives vary from > near-instantaneous to several seconds response time. Next stupid question: I assume that part of the adapter POSTing is a bus reset. Why does FreeBSD issue a SCSI bus reset at all? I understand that you would need to wait this long if you issued a reset, and I understand a reset is necessary to detect newly plugged "hot plug" devices. However, it seems to me that the use of a reset following a power on is specious and unnecessary, even if there might be reason for root to be able to issue such a command (and thus lock up the box for up to 31 secons). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message