Date: Sun, 4 Oct 1998 03:04:58 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: arg@arg1.demon.co.uk (Andrew Gordon) Cc: karl@Denninger.Net, current@FreeBSD.ORG Subject: Re: Long SCSI probes (was Re: Long IDE probes?) Message-ID: <199810040304.UAA21515@usr06.primenet.com> In-Reply-To: <Pine.BSF.3.96.980930231258.20359B-100000@server.arg.sj.co.uk> from "Andrew Gordon" at Sep 30, 98 11:20:33 pm
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> 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
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