hdparm question

[Jude DaShiell <jdashiel@shellworld.net>]

I have postgresql running on an ide type system with a 300GB hard drive. 
For some reason the command hdparm -W 0 /dev/hda fails with error0x04 so 
drive cacheing can't be turned off by hdparm on this type of drive so far 
as I now know.  There is all of that lvm stuff on the system running so 
it's possible hdparm and lvm might not like each other all that much and 
in my case generate this error.  That or there's something else I need to 
do.