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PostPosted: Thu Aug 26, 2004 7:45 pm 

Joined: Tue Apr 27, 2004 9:52 am
Posts: 73
hi there
Me and Mick FUzz from have spent the day messing about with linux video, threres a few teething issues and was wondering if anyone might be able to help via irc tommorrow? we will be online from the mid morning and would really appreciate it :-)

the project is to create a box with tools on it to capture and create mpeg1 and other internet friendly files. and to have an archive of our undercurrents and indymedia video files in a searchable format.

one specific problem we are having is enabling dma on the harddrives to speed them up for video capturing. we get an operation not permitted error.

nice one


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PostPosted: Thu Aug 26, 2004 8:25 pm 
Site Admin

Joined: Sun Mar 14, 2004 3:17 pm
Posts: 4492
Location: Loveland, Colorado, USA
To turn on DMA on a drive run a command like:

hdparm -d1 /dev/hda

I know you tried that and it didn't work. Perhaps there's something you can set in your BIOS as well (?). Or it may be that the drive/controller can't do it. What kind of gear do you have?

To find out about your hardware you can run:


Then you could google that gear and the word "hdparm" or "dma" and see if anything comes up.


 Post subject:
PostPosted: Fri Aug 27, 2004 2:19 pm 

Joined: Sun Mar 14, 2004 11:08 pm
Posts: 83
Location: LOWMEM
just an idea, but check you have 80-pin cables, and not 40-pin on the hard drives. Not sure if this puts a limitation on how the drive params work?

There is also some other tweaks you can do from disk i/o. (the brackets are my comments)

hdparm /dev/hda (read current settings)

hdparm -c3 (32 bit transfer) -d1 (dma) -X69 (udma5) -m16 (transfer 16 sector not 8) -u1 (mask interrupt) -a16 (largefileoptimised) -W1 (write caching) -K1 (retain this setting if software resert or error)

I would test each element individually though [AND BENCHMARK]. We found that a combination gave up to a 40 percent in increase in performance. But DANGER overdoing it can damage the drive I think. (The one time things went fine UNTIL the acpi tried to spin down the drive, and then it all went crazy starting and stopping and clucking and clicking and it hanged up, that drive is still going, but very flaky -)

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