Enabling DMA for CD and HD

Forum: HD Install
Topic: Enabling DMA for CD and HD
started by: ale_ryu

Posted by ale_ryu on Jan. 04 2005,22:38

I recently installed DSL on a P180(overclocked P166) with 32mb RAM, a 52x LG CD Device and a 4gb Seagate HD.
I was wondering if any of you could tell me how to enable DMA for the HD and the CD Device without having to reinstall the whole system again and without having to insert the DSL CD everytime I boot my PC.
Thnx in advance.
Ale :laugh:

Posted by green on Jan. 05 2005,00:13

First, read the forums regarding DMA and hdparm (search those terms)

< http://damnsmalllinux.org/cgi-bin....=hdparm >

First, make a backup of any file you feel like editing. Trust me.

Next, type this line in a console or terminal at the command prompt:
(this will do read speed tests of buffer-cache and buffered disk reads)

hdparm -tT /dev/hda

Do that four or five times so you will get an idea of the average speeds.

Remember: /hda represents the drive you want to test the read speeds on.

The type:

hdparm -d1 /dev/hda

Then type:

hdparm -tT /dev/hda

again to see if the speeds have increased.
If the speeds are to your liking, then you can add the hdparm line to bootlocal.sh

which is located in /opt

Open terminal with root access or open a regular terminal then type:

sudo su

then type:

beaver (or scite or whatever editor you want to use, beaver works for version 0.9.1, scite works for 0.8.2 up to 0.8.4 and maybe more, but those are the only ones I've tried it on)

when the editor opens, go to file:

/opt/bootlocal.sh

add the hdparm line at the end:

hdparm -d1 /dev/hda

This is what I've done. I'm a noob, so no promises. Do at your own risk.
Also, search the web for hdparm and you find several things written on all the various hdparm actions, their explanations and uses.

Good luck.

Posted by cbagger01 on Jan. 05 2005,04:58

I like green's approach better, because it lets you choose the drives to enable dma.

However, if your hd and CDROM drive both can tolerate dma without problems, you can boot with:

dsl dma

and dma access should be enabled for all devices.

Some cdrom drives do not like this and you will get cloop errors. If so, reboot and use green's method instead.