[mythtv-users] OT: 160 gig WD - $40

Brad Templeton brad+myth at templetons.com
Mon Mar 21 20:37:08 UTC 2005

On Mon, Mar 21, 2005 at 07:18:07AM -0500, Jeff wrote:
> With IDE you only want one drive on a cable (controller
> port) as only one drive can transfer data at a time. You can
> get a 2nd IDE controller card (better to get a S/ATA card perhaps
> at this point) and run 3 HD's using the 4th channel for your CD/DVD
> drive. Best to get the largest disks you can (but look for 3yr
> warranties which tend to be more expensive).

What do benchmarks say about this?  Current systems and drives come with
100 megabyte/second or 133 megabyte/second ATA bus speeds.   The 7200
rpm drives, on the other hand, tend not to be able to sustain data
rates more than about 60 megabytes/second, and of course rarely are they
actually doing this, they spend most of their time seeking or idle.

So, is it really true that you only want one drive on the cable?  Are
there some benchmarks out there showing the throughput for the 2 on
one cable vs. 2 on 2 cables?   I am sure there is some loss here, but
how much is it?

As you probably know, MythTV tends to rarely need more than 2 megabytes/second
of disk bandwidth to play or record even an HD stream.  This is so far below
the capacity of these channels that it seems odd to me if there would
be much gained by buying additional disk controllers to squeeze out
a little more bandwidth, but I am curious as to the numbers you may have.

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