From owner-freebsd-hardware Wed Feb 24 18:36:16 1999 Delivered-To: freebsd-hardware@freebsd.org Received: from alcanet.com.au (border.alcanet.com.au [203.62.196.10]) by hub.freebsd.org (Postfix) with ESMTP id 15ED414BF3 for ; Wed, 24 Feb 1999 18:36:11 -0800 (PST) (envelope-from peter.jeremy@auss2.alcatel.com.au) Received: by border.alcanet.com.au id <40323>; Thu, 25 Feb 1999 13:24:52 +1100 Date: Thu, 25 Feb 1999 13:35:45 +1100 From: Peter Jeremy Subject: Re: Tagged queueing and write cache on WDE SCSI drives To: ken@plutotech.com Cc: hardware@FreeBSD.ORG, ru@ucb.crimea.ua Message-Id: <99Feb25.132452est.40323@border.alcanet.com.au> Sender: owner-freebsd-hardware@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org "Kenneth D. Merry" wrote: >It may be single threaded, but since it goes through the filesystem, there >can be multiple outstanding I/O requests. That makes sense - the filesystem is doing write-behind so there can be lots of outstanding I/O requests. That said, since it is a sequential write, there isn't much scope for command re-ordering (the inode and bitmaps will be being updated, but fairly infrequently) - which is the whole point of tagged queueing. Peter To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message