[Ti] 60gb TravelStar - quick question

[Kynan Shook]

Sherman Gregory <sherman at qualcomm.com> writes:
> Seek time is of course critically important to the real usable speed 
> also.

Seek time is important, but is not a function of rotational speed; what 
IS a function of rotational speed is rotational latency:  Seek time 
positions the heads over the proper track (aka cylinder-a concentric 
circle a certain distance from the center of the platters).  But if the 
first bit you want to read passed by the heads just before they arrived 
at that cylinder, you have to wait for the entire time it takes for the 
drive to make a full rotation before you can begin reading.  This 
generally comes to slightly more than 1/100 second, an ETERNITY as far 
as a computer processor is concerned (your processor would run 10 
*million* instructions in that time).

In reality though, I'd rather have the lower power consumption and 
lower noise level of a 4200 RPM drive than the lower latency and 
possible extra speed of a 5400 RPM drive.

BTW, drives are generally 4200, 5400, 7200, 10,000, or 15,000 RPMs.  I 
don't think any 4800 RPM drives exist.


Kynan Shook
kshook at mac.com
http://homepage.mac.com/kshook/index.html