[Sussex] Hard drive question

[Richie Jarvis]

linux at oneandoneis2.org wrote:
> Hi all,
>
> Google is giving me conflicting answers to this question, so I thought 
> I'd try asking real people instead :o)
>
> Hard drives with multiple platters & therefore multiple heads: When 
> writing to the disk, is only one head active at a time, writing the 
> whole file to one platter; or do all the heads write at once, with 
> head one writing the first bit of the file, head two writing the 
> second bit, and so on?
>
> I was under the impression that only one head could write at any one 
> time, and most sites seem to bear this out, but others swear blind 
> that all platters are written to at once, and you can see how that 
> would make for a speed increase. . .
>
> Anybody know for sure?
>
> Thanks
>
> Dominic
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