Just finished catching up on the last 360 or so messages to this list (been busy with exams lately, not reading email). Forgive me if I'm a couple of days late jumping into this thread, but I just have to ask....
On Thursday 26 June 2003 17:16, Matthew Gregan wrote: > On Thu, Jun 26, 2003 at 05:00:42PM +1200, Carl Cerecke wrote: > > Is hdparm -t an accurate measure of hard drive speed? > > No. Not even close. Out of curiousity, can you justify this? Only, I sometimes use it to make comparisons between different drives, and it seems quite useful. Sure it's not a good indicator of filesystem performance, or anything like that that really matters, but for comparing raw transfer speed of two different pieces of hardware (ie. "hard drive speed", as per the origional question), how is this not a good measure? Secondly, while on the topic of hdparm... I notice I get significantly better performance with DMA mode enabled on my hard drive (not surprisingly!), which I can set with: hdparm -d1 /dev/hda (I had this in a script that runs at boot) I recently upgraded my kernel from 2.4.10 to 2.4.21, compiled from source with basically the same .config as 2.4.10 had. It all works fine, except now when I try the above hdparm line (as root) I get: HDIO_SET_DMA failed: Operation not permitted If I boot the old kernel it all works fine. If anyone has any clue why this might be, I would love to know. Cheers, Gareth
