BRUCE STANLEY wrote:
How did you go about disabling dma?
Typically it's: # hdparm -d 0 /dev/hdX
Manuel BERTRAND manuel.bertrand@lif.univ-mrs.fr wrote:
Change your IDE cable, be happy. (old IDE have fewer wire)
Well, it all depends.
Normally during POST, if the BIOS detects an UltraDMA Mode 3** (50MBps**) or higher** signaling, and the cable is not augmented with 40 ground wires (the 80-conductor type), it is supposed to reduce the signaling to UltraDMA Mode 2 (33MBps). But the OS and/or drive might optimize its signaling to a higher rate once the kernel loads, or at boot-time optimization.
[ **NOTE: UltraDMA mode 3 (50MBps) and 4 (66MBps) are commonly referred to as Ultra66 ]
But it could be a variety of problems: - Cable used (40-pin v. 40-pin+40-ground aka "Ultra66 cable") - Multiple ATA devices on a channel conflicting - Hdparm optimizing the ATA channel and IDE disk incorrectly - Many, many others
But in every case I had, when the drive _had_ worked prior without issue, it was a kernel upgrade and that ATA driver. As I mentioned before, there have been many documented cases of this, as well as the politics of the ATA code in the kernel (around 2.4.18-19 IIRC).