Hard Drive Tweaking problems

[z00s]

I started messing around with hdparm and noticed that the I/O Support was set to 0, multcount was set to 0, and using_dma was set to 0. I decided to set I/O to 1, DMA to 1 and multcount to 16. My hard drive is capable of a multcount of 16 because when running -i it came back with 16 max_mult_count. For some reason, when I do a -c 1 -d 1 and then run -t, it gives me no improvement on the benchmark. I also noticed that after running the benchmark it automatically switches c to 0 and d to 0. I tried doing -c 1 -d 1 -k 1, I ran the benchmark, and it came back with HDIO read/write error. This time, however, the settings stayed the same. Anyone have any ideas?

[z00s]

I tried removing -d 1 from the line and it worked. I am getting immensely improved hard drive performance. Apparently my system doesn't particularly care for having a forced -d 1, because it just fatal errored and hosed itself. Taking a look at my CMOS read out, my hard drive is currently running in UDMA4. In Linux, why would setting the UDMA on cause a crash like this, if my hard drive supports UDMA4?

[mdwatts]

Hard to tell. You would probably need to read all the documentation, FAQ's etc. on hdparm to see if there's an answer.