SATA or SCSI drives - Multiple Read/write speeds.

Robert G. Brown rgb at phy.duke.edu
Mon Dec 8 20:24:44 EST 2003


On Mon, 8 Dec 2003, Mark Hahn wrote:

> | read the reviews and the hype about SATA being better than IDE/ATA and 
> | almost as good as SCSI, even better in a couple of areas.
> 
> <sigh>
> 
> 
> | I have talked to our computer people but they don't have enough 
> | experience with SATA drives to give me a straight answer.
> 
> there's not THAT much to know.

But what there is is a pleasure to read, as always, when you write it.
One tiny question:

> | My concern is regarding multiple disk read/writes.  With IDE, you can 
> | wait for what seems like hours while data is being read off of the HD. 
> 
> nah.  it's basically just a design mistake to put two active PATA disks 
> on the same channel.  it's fine if one is usually idle (say, cdrom or 
> perhaps a disk containing old archives).  most people just avoid putting 
> two disks on a channel at all, since channels are almost free, and you 
> get to ignore jumpers.

So, admitting my near total ignorance about SATA and whether or not I
should lust after it, does SATA perpetuate this problem, or is it more
like a SCSI daisy chain, where each drive gets its own ID and there is a
better handling of parallel access?

The "almost free" part has several annoying aspects, after all.  An
extra controller (or two).  One cable per disk if you use one disk per
channel.  The length thing.  The fact that ribbon cables, when they turn
sideways, do a gangbusters job of occluding fans and airflow, and with
four or five of them in a case routing them around can be a major pain.

There is also a small price premium for SATA, although admittedly it
isn't much.  So, in your fairly expert opinion, is it worth it?

   rgb

-- 
Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu



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