[mythtv-users] Where the bottleneck?

Calvin Dodge caldodge at gmail.com
Sat Jan 26 07:13:04 UTC 2008

On Jan 25, 2008 10:56 PM, Mitch Gore <mitchell.gore at gmail.com> wrote:
> Yes i have,  it doesnt appear that i can set DMA on. My new system drive is
> IDE but the recording drivers are SATA.

Run hdparm -Tt on the SATA drives. If you get I/O greater than, say, 8
megabytes a second, then I'm pretty sure DMA is enabled (my experience
with older IDE drives was that they maxed out at about 4 megs per
second (at the most) if DMA was disabled, regardless of drive or CPU
speed). For example - on one system here "hdparm /dev/sdb" shows no
way to control DMA, but when using "-Tt" shows a raw read rate of
about 74 megs/second (cached from controller is 220/megs/second), so
I'm pretty certain DMA IS enabled.


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