Problems with HDB after Knoppix install - DMA problem ?

[fowlertrainer]

Hi !

I have 2 HDDs.
When I use Suse Linux, I get this problem too...

When I installed Knoppix on my machine, it is alway say "creating /etc/fstab" on boot.
The problem is that the second hdd is very old. The Windows is slowed to 60-90% CPU perf. when I copy to this hdd.

The Suse Linux is slowed down only on boot, it is waiting for 5 mins...
The Knoppix in /fstab creation is slowing down too, and the dmesg is show this:

hdb: dma_timer_expiry: dma status == 0x61
hdb: error waiting for DMA
hdb: dma timeout retry: status=0x58 { DriveReady SeekComplete DataRequest }

hdb: dma_timer_expiry: dma status == 0x61
hdb: error waiting for DMA
hdb: dma timeout retry: status=0x58 { DriveReady SeekComplete DataRequest }

hdb: dma_timer_expiry: dma status == 0x61
hdb: error waiting for DMA
hdb: dma timeout retry: status=0x58 { DriveReady SeekComplete DataRequest }

hdb: dma_timer_expiry: dma status == 0x61
hdb: error waiting for DMA
hdb: dma timeout retry: status=0x58 { DriveReady SeekComplete DataRequest }

1.)
Is an DMA problem ?
How to I set the DMA off for the second hdd (hdb) ?

2.)
How to I prevent this hdd auto detection, and fstab auto write in knoppix ?

Thanx for helps !
ft

[shah]

It's dma problem.
1) I don't know if this will work. You could try create a script something like this:

#!/bin/sh
/sbin/hdparm -d0 /dev/hdb

Save this file in /etc/rcS.d and name it something like S20hdb.sh. Then reboot.
If this doesn't work, you have to disable dma on all ide by ...append nodma in your lilo.

2) I don't know how to prevent hdd from autodetection. But for prevent knoppix from autowrite your fstab...append nofstab in lilo.

ex:
image=/boot/vmlinuz-2.6.5
label="Linux(2.6)-2"
initrd=/boot/initrd.img-2.6.5
append="ramdisk_size=100000 lang=us apm=power-off nomce nofstab nodma "
read-only[/b]

[fowlertrainer]

What doing the option "nodma" ?

1.
disable dma on boot for accessed disks

or

2.
disable dma for all disk, so Linux is don't use that when it is started

?

I think that 1. is the better, but I want to know it.

Thanx:
ft

[shah]

The purpose of DMA is to accelerate your harddisk access. But on some old harddisk, DMa is not supported, by enabling it will cause that harddisk fail to read and write properly.

By disabling DMA, doesn't meant you can't access your harddisk. Knoppix will acces it, but slower.

What I try to do in
1) is to disable DMA on that particular harddisk. Meaning, only unsupported harddisk will run slow (DMA disable), and the other harddisk can take advantage over DMA.

2) By appending nodma in your lilo, all harddisk will not be able to use DMA. Meaning, all harddisk including supported DMA also will run slower.
See the example how to add nodma in your lilo, and don't forget to run command: lilo in root konsole after you edited your lilo and saved it.