[plug] HDD performance

[John Summerfield]

> Mike Holland wrote:
> > 
> > On Thu, 18 Nov 1999, John Summerfield wrote:
> > 
> > > [root at possum summer]# /sbin/hdparm -ti /dev/hda
> > 
> > >  RawCHS=17662/16/63,
> > 
> > > closely related to the rotation speed and the real track capacity (not
> > > what the BIOS  thinks or what the drive says).
> > 
> > So is the RawCHS quoted above correct? Do drives really have 16 heads?
> > 
> > Mike Holland <mike at golden.wattle.id.au>            Perth, Australia.
> >                           --==--
> Id suggest maybe 4 heads and a lot more sectors.
> Just find out how many platters it has and x 2 for maximum head
> numbers. I have never seen more than 3 platters in a 'domestic' 
> type of drive. thus maximum 6 heads.
> 
> The raw readings are still translated by the drive to get around the
> archaic ide address field limitations.
> 
> For a bit more information, go to http://www.quantum.com
> and read the spec sheets on the new fireballs. Pretty Eye opening.

Seagate have good specs pages too. I think some Seagate drives have four 
platters.

Any resemblance between what geometry the drive claims and what is really 
there is coincidental; they tell lies to fool obsolete BIOSes into doing 
something reasonable.

Possibly a program could be written to detect the real geometry (and it 
may vary across the surfaces!!), but it would have to counter the effects 
of on-drive cache and read-ahead.

-- 
Cheers
John Summerfield
http://os2.ami.com.au/os2/ for OS/2 support.
Configuration, networking, combined IBM ftpsites index.