[plug] HDD performance

[Mike Holland]

On Thu, 18 Nov 1999, John Summerfield wrote:

> [root at possum summer]# /sbin/hdparm -ti /dev/hda

>  RawCHS=17662/16/63, 

So thats 0.5MB/cyl at 7200rpm = 60MB/sec theoretical max at the heads,
right? Can the drive read all heads simultaneously?

>  Timing buffered disk reads:  32 MB in  1.91 seconds =16.75 MB/sec

Yowser! I get < 4 MB/sec with my ordinary drive. Are these figures
very meaningful?

> This is a 7200 rpm drive in a PII-233, LX chipset, UDMA/33. 
> Note the cache size;-)

What difference does 2MB vs 0.5MB make on a  32MB transfer?
I'd expect it to be proportionally faster than a 5400rpm at best. Anything
else different?

> 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.
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