From owner-freebsd-current Mon Sep 14 10:39:50 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id KAA10920 for freebsd-current-outgoing; Mon, 14 Sep 1998 10:39:50 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from mail.camalott.com (mail.camalott.com [208.203.140.2]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id KAA10807; Mon, 14 Sep 1998 10:39:25 -0700 (PDT) (envelope-from joelh@gnu.org) Received: from detlev.UUCP (tex-30.camalott.com [208.229.74.30]) by mail.camalott.com (8.8.7/8.8.5) with ESMTP id MAA29633; Mon, 14 Sep 1998 12:41:04 -0500 Received: (from joelh@localhost) by detlev.UUCP (8.9.1/8.9.1) id MAA08622; Mon, 14 Sep 1998 12:38:54 -0500 (CDT) (envelope-from joelh) Date: Mon, 14 Sep 1998 12:38:54 -0500 (CDT) Message-Id: <199809141738.MAA08622@detlev.UUCP> To: Terry Lambert CC: tom@uniserve.com (Tom), gpalmer@FreeBSD.ORG, irc@cooltime.simplenet.com, freebsd-current@FreeBSD.ORG In-reply-to: <199809132343.QAA23937@usr04.primenet.com> Subject: Re: Download of FreeBSD 3.0-SNAP From: Joel Ray Holveck Reply-to: joelh@gnu.org References: <199809132343.QAA23937@usr04.primenet.com> Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > While this is fine for disks that can support multiple outstanding > commands pending simultaneously (giving them something to sort), > it is less of a good idea for stupid disks that must be sent > commands serially. Like, oh, say, E/IDE disks. > The FreeBSD E/IDE driver supports queued tagged commands, but > few E/IDE drives have this capability (in fact, I am not aware > of *any* that support this portion of the spec.). > It should be noted that some SCSI devices don't support tagged > command queuing, either (but we don't buy those, since they are > in the minority). I'm no disk expert, so please tell me: what is tagged command queueing? Is it the ability to have multiple outstanding requests, with the device reordering the requests for optimal efficiency, and relying on a cookie in the header to differentiate between requests? Best, joelh -- Joel Ray Holveck - joelh@gnu.org - http://www.wp.com/piquan Fourth law of programming: Anything that can go wrong wi sendmail: segmentation violation - core dumped To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message