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. -- Les Mikesell lesmikesell at gmail.com