Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!ncar!boulder!sunybcs!bingvaxu!leah!itsgw!batcomputer!cornell!uw-beaver!mit-eddie!bbn!uwmcsd1!ig!agate!ucbvax!ucsd!ucsdhub!hp-sdd!hplabs!hpl-opus!hpccc!samc
From: samc@hpccc.HP.COM (Samuel Chau)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Re: Perstor claims (was Re: RLL on standard disks)
Message-ID: <5060023@hpccc.HP.COM>
Date: 17 May 88 22:06:36 GMT
References: <220@octopus.UUCP>
Organization: HP Corporate Computing Center
Lines: 36

I have been testing the Perstor PS180 ERLL card with various drives for
several months now.  Whether this card will work with a particular drive
depends heavily on the timing margins available, especially at the
innermost cylinders.  Of the three Seagate ST-251-1 drives I had played with,
only two worked smoothly.  The third one had significantly lower margin
figures listed in the accompanying tech sheet.  The last 200 cylinders
of that drive were unable to hold valid data.  Over half of the clustors
in that region were spared by the high-level format program.  And I chose
not to trust any data to any of the surviving clustors.

To be safe, when purchasing a drive for use with the Perstor PS180, one would
almost need to ask for several drives of the same make and model to be
displayed at once.  Then the one with the highest margin figures listed
(on the tech sheet) would be the best choice.  The number of hard errors is
only of secondary concern, since the drive that I now use with the PS180
has 9 hard errors, whereas the one that failed has 0 hard errors.

Older drives can be expected to fail rather miserably with the PS180.  I
have tried two Fujitsu M2243AS 72MB mechanisms made two years apart without
a bit of luck with either drive.  I would think RLL qualified drives should
have the best chance of working with a demanding controller like the PS180,
but they may not provide the most cost effective means of getting more disk 
space.

I, too, would like to hear from others who have had experience with the
Perstor PS180 card.

*****************************************************************
*                           DISCLAIMER                          *
*  The opinions expressed above are strictly my own, not those  *
*  of Hewlett Packard Company.                                  *
*****************************************************************

Sam Chau
HP Cupertino
...hplabs!hpccc!samc
(408) 447-0238