[mythtv-users] OT? Hardware Differences

R. G. Newbury newbury at mandamus.org
Thu Apr 13 14:25:11 UTC 2006


This is a little offthread but it does affect my use of myth. And this 
list has shown that it is a source of deep knownledge about linux.

I have 2 exactly similar 40G hard drives: model IC35L040AVVN07-0. Bought 
the same day, same order.

Playing with hdparm I can set the master /dev/hda to use udma=5 (using 
the -X69 parameter.
The slave /dev/hdb will only do udma=2.

As a result, although the cached read speeds are similar at about 
730MB/s, the buffered read on hdb is 19.6MB.s versus 45 MB/s on hda

The only difference I can see is that hdb reports:

AdvancedPM=yes: unknown setting while hda reports AdvancedPM=yes: 
disabled (255), and attempting to set APM on hdb gives the following 
error:  HDIO_DRIVE_CMD failed: Input/output error

It appears that neither APM nor acoustic management features actually 
get changed/set when I use hdparm... Weird!

I can get/set the other commands/switches on the drive so this is more 
than a little weird.

I want to move this drive to my mythbox and do the OS install onto it, 
and use the entirety of the present 120G for recording...But the 
throughput problem puts this plan in doubt. Any thoughts anyone.

Geoff


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