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From: tissot@nicmad.UUCP (Kevin Tissot)
Newsgroups: comp.sys.ibm.pc
Subject: Re: ST251 28ms drive
Summary: Seagate uses stepper motors
Message-ID: <3115@nicmad.UUCP>
Date: 31 Aug 88 03:42:33 GMT
References: <1741@spdcc.COM>
Organization: Nicolet Audiodiagnostics
Lines: 22

In article <1741@spdcc.COM>, eli@spdcc.COM (Steve Elias) writes:
> there are two versions of the st251 -- one has 40ms access time,
> the other has 28ms access time.
> 
> how does seagate do this?  the 28ms version (mlc-1 marked on drive)
> does indeed show an access time of 28ms when run through various
> disk test programs.  but!  its track to track seek time seems to 
> be much slower than other 28ms drives.  

 Most drives in the 28ms and below range rely on voice coil actuators
for positioning the heads. Seagate is the only vendor (that I know of)
which gets this kind of speed from stepper motor drives. Seems they
do some tricky stuff to do this, which in my experience makes the 
drives much more sensitive to temperature variations and mounting
configuration. Result: probably the least expensive drive in this
performance category, but you take your chances with data reliability.
The choice is up to you...

-- 
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Kevin Tissot                     {ucbvax,harvard,rutgers}!uwvax!nicmad!tissot 
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