Added IDE drive to SATA-based system, and found it was sloooow
 

This was an existing system with 2.6.10-6-686-smp kernel. It had already two SATA drives, and since there were no more SATA positions available, I added an IDE drive. Strapped it as Master (I think; honestly there was no documentation available; anyway it worked together with the CDROM drive).
It works well, no problem, but it is rather slow: buffered disk reads at 1.69 MB/s.
On investigation, I found that DMA is OFF, but, unfortunately, hdparm -d1 refused to turn it ON (Operation not permitted).

How do I get this disk up to speed? Do I need a different driver? lsmod shows that ide_disk is present (I assume that that is the IDE driver).
And, if I need another one, is there a good way to cross-compile it? (it is a production machine, so I'd rather not interrupt work if I can avoid it).

assuming your cdrom was in already that should have been the master and you can only have one master and one slave.....if you agree....you must go to Mandriva now oh slave....heh heh only joking

reset the jumper for the cdrom after writing down its current position

normally there are 3 positions master slave and cable select

unfortunately on a wide ribbon....hdparm will imho only do the speed for the slowest device so you may find it better for the moment to remove the lead out of the cdrom and retest speeds for the ide

2) a live cd such as knoppix can detect the jumpers etc

ide should AFTER suggestions be hda and if cd still in....its hdb
so 2 hda....no go and well you get the general drift.

3) if you remove the ide drive and write down some of its details ...google should tell you the specs and then you can find a manual etc