Hi, Yes, you need to pass a parameter to the kernel at boot time - I use Lilo, and have a line :
append = "resume=/dev/hda5 splash=silent acpi=off"
this contains the kernel parameters, so just add a further parameter with the elevator=noop (or whatever). Then, in the case of Lilo, rerun the Lilo program before rebooting. I think (but I'm not sure) that incorrect parameters are ignored, so you'll have to check your boot logs to be sure that it's taken effect.
I'm also no sure what are the appropriate parameters, 'deadline', 'noop' and 'as' I'd guess.
You can also (OK I can with a 2.6.10 kernel - I assume you can with a 2.6.4 kernel) - change the scheduler on the fly.
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