ST-251 Drives as RLL?

neal at mnopltd.UUCP neal at mnopltd.UUCP
Wed Dec 20 02:01:40 AEST 1989


@ >->out there has taken an Seagate ST-251 42MB 40ms MFM drive, and formatted
@ >
@ >Yes. This will work.  For 5 months and 27 days.   It will roll over and die
@ >with skillions of bad blocks at 6 months.   Anyone who tells you otherwise

@ We have several 251's here that have survived in excess of a year running
@ RLL.  In fact, not >one< has ever failed to hold a format once it got past
@ the first 24 hours.

@ EVERY other drive we've ever tried (251) has formatted and played RLL --
@ some for more than 2 years.  No trouble at all, and only one or two grown
@ bad blocks over that time (which happens with about the same frequency on
@ those which we have MFM).

@ It will, however, void your warranty with Seagate :-)

@ --
@ Karl Denninger (karl at ddsw1.MCS.COM, <well-connected>!ddsw1!karl)
@ Public Access Data Line: [+1 708 566-8911], Voice: [+1 708 566-8910]
@ Macro Computer Solutions, Inc.		"Quality Solutions at a Fair Price"
@ 

Ok, Karl; I knew we were going to get different opinions on this.  I have worked
with three people who put in 251/RLL configs; all of them died at 6 months.  All
later got an MFM controller and the SAME drive worked fine and is working now.

SO assuming we are both right in our experiences, and assuming that SEVERAL 
means 3 then we have:
	3 drives OK
	3 drives Dead

And one can expect a 50% chance of a dead drive in 6 months.  Now also to 
consider:
	Aren't there two variants of the ST-251?  One with plated media and
	one without?  (plated media being required for acceptable RLL usage?)

In the spirit of the season, let's not engage in an extended ankle biting 
display on this...

Neal Rhodes
Lilburn (atlanta) GA 30247
uunet!emory!jdyx!mnopltd!neal Or uunet!gatech!stiatl!mnopltd!neal



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