On 12/23/2009 08:15 PM, Les Mikesell wrote: > Timo Schoeler wrote: >> On 12/23/2009 07:29 PM, John R Pierce wrote: >>> Ross Walker wrote: >>>> I think you might be confusing CAV with CLV of optical drives. >>>> http://en.m.wikipedia.org/wiki/Constant_Angular_Velocity >>>> >>> no, I'm not. most HD's ('green drives' complicate this some) spin at >>> a constant RPM, so the rotational latency is the same on the inner and >>> outer tracks, an average of 1/2 turn, about 4mS for a 7200 rpm drive, >>> and 2mS for a 15000rpm enterprise drive . However, the data rate >>> changes. so the outer tracks have more data on them, which is read at a >>> higher speed in megabytes/second >> >> That's why in ancient times one was setting up partitions so that the >> swap area was the the beginning (mostly the outer tracks of the HD -- >> never hit a drive that did it the other way round) of the drive. >> >> Try it yourself, get a spare HD and create three partitions on it, two >> smaller ones at beginning/end of the drive, the third one filling the >> gap between them; install bonnie++ and compare the transfer rates. > > But these days, nothing should ever be reading from swap, although you > might write a bit there. If it does, buy some more RAM instead of > worrying about disk performance. Sure, absolutely no question; *but* in the (ancient) times it was important, it was 'nice' to have it as fast as possible, i.e. on the fastest section(s) of the used HDs. So... Timo