Date: 28 Sep 2000 09:56:19 +0200 From: Dag-Erling Smorgrav <des@ofug.org> To: John Galt <galt@inconnu.isu.edu> Cc: Dan Langille <dan@langille.org>, chat@FreeBSD.ORG Subject: Re: CD writers - recommendations Message-ID: <xzpk8bxq7a4.fsf@flood.ping.uio.no> In-Reply-To: John Galt's message of "Wed, 27 Sep 2000 12:00:35 -0600 (MDT)" References: <Pine.LNX.4.21.0009271146100.28764-100000@inconnu.isu.edu>
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John Galt <galt@inconnu.isu.edu> writes: > Adaptec 1542 has a Z-80 onboard to share in the disk processing tasks, I'm > betting that the better cards have beefier processors. I have never seen > a GP processor on an IDE card. [more blathering elided] IDE used to be processor-intensive back when most disks only supported PIO, but it's not any more. The reason you can't see a processor on an IDE adapter, by the way, is that IDE, as its name suggests, places most of the logic on the disk itself. That's also the reason why IDE channels have masters and slaves: the controller is actually located on the master, not on your motherboard or IDE adapter board. The reason why ATAPI CD-ROM burners are so sensitive to CPU load is that they don't support disconnection or tagged queueing, so commands must be sent sequentially and the CPU must wait for them to complete. DES -- Dag-Erling Smorgrav - des@ofug.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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