[Sussex] Hard drive question

[linux at oneandoneis2.org]

Quoting Richie Jarvis <richie at helkit.com>:

> I would have thought that it would depend on the manufacturer of the
> drive and controller software as to how it works.  My impression has
> always been that to provide greater access speeds, bit 1 goes on the
> top of platter 1, bit 2 goes on the bottom, bit 3 goes on the top of
> platter 2, etc, etc....
>
> I can't see any reason why the heads would only be able to be used one
> at a time, unless the controller is restricting it?
>
> Richie

Undoubtedly a hard drive that could read & write too all platters  
simultaneously would perform much faster. But websites all over the  
place state that there are no such drives:
http://www.dansdata.com/io012.htm (Near the bottom)
http://www.webopedia.com/DidYouKnow/Hardware_Software/2002/InsideHardDrive.asp
http://www.pcguide.com/ref/hdd/op/heads/opNumber-c.html

And so on, while others claim that they in fact do:
http://www.tgpd.fsnet.co.uk/tutorials/hardware/hard-drive/hard-disk_and_controllers.html

Hence my confusion. . .