From owner-freebsd-hackers  Fri Aug 18 14: 5:50 2000
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To: Robert Sexton <robert@kudra.com>
Cc: Jonathan Laventhol <jonathan.laventhol@imagination.co.uk>,
	freebsd-hackers@FreeBSD.ORG
Subject: Re: Cheap 1000Gbyte machine 
In-Reply-To: Message from Robert Sexton <robert@kudra.com> 
   of "Fri, 18 Aug 2000 15:57:48 EDT." <20000818155748.A42398@tabby.kudra.com> 
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Date: Fri, 18 Aug 2000 14:04:57 -0700
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From: Parag Patel <parag@cgt.com>
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On Fri, 18 Aug 2000 15:57:48 EDT, Robert Sexton wrote:
>
>Can IDE drives release the bus during seeks?  Historically thats been
>the big advantage of SCSI: Two IDE drives are no faster than one IDE
>drive, while SCSI scales in performance.

How about a single IDE (master) drive per controller, that is, no slave
drives at all?  This would halve the number of available drives per card
(or require twice the number of cards) but essentially would use the PCI
bus as a multiplex bus between drives instead of SCSI.

You're still pretty much stuck waiting for one command to finish before
another can be sent to a drive though, unlike SCSI drives.  Still a lot
cheaper tho'.

I suppose another trick would be to arrange your vinum partitions and
drive layout so that master and slave drives are never accessed
simultaneously so one won't block access to the other.


	-- Parag Patel


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