Xref: utzoo comp.periphs:942 comp.sys.ibm.pc:15538
Path: utzoo!attcan!uunet!husc6!uwvax!gumby!g-thaler
From: g-thaler@gumby.cs.wisc.edu (Maurice Thaler)
Newsgroups: comp.periphs,comp.sys.ibm.pc
Subject: Re: RLL on standard disks
Message-ID: <1596@gumby.cs.wisc.edu>
Date: 14 May 88 05:56:15 GMT
References: <10831@steinmetz.ge.com>
Reply-To: g-thaler@gumby.cs.wisc.edu (Maurice Thaler)
Distribution: na
Organization: U of Wisconsin CS Dept
Lines: 46
Summary:Perstor might work

I have recently ordered and am waiting for an ARLL card from Perstor 
out of Scottsdale AZ. This is a new 16bit controller for AT's and 386's
which is supposed to run w/ any hard disk which you could normally use
with your machine. It also has support for the >1024 cylindar disks. They
have two versions of this unit one of which has RAM on the card to perform
caching to improve the data transfer rate.  According to the stats from
CORETEST2.7 my hard disk (ST 4096 80Megabyte) gets about 250k/sec with a
standard WD control card.  The tech at Perstor said that in my 386, I can
expect to get a transfer rate close to 2000k/sec with this new card and
the size will be 1.9x or aprox 150 meg. 
I know that many BBS's around the country have been using this company's 
earlier efforts (they have an 8bit card which works in XT's and AT's)
for extended periods of time without many complaints. I am using one
of these older cards on a BBS I  run and so far it has been trouble free.
I am using this older card w/ an ST251-1 40meg (now 76Meg). This is NOT
an RLL approved drive but has been one of the most popular drives to use
with the earlier Perstor card. They give a drive table in the install manual
that lists quite a few different head/cylinder counts and the will apprently 
burn custom rom's for unusual drives. I think that the new 16bit card would be
much more universal since it is not dependent on its rom, you can use the CMOS configuration that comes w/ your AT.
I asked the tech about all the concerns about abusing drives will RLL cards. 
He said that many RLL  cards apply data at a higher frequency (I might be 
misquoting him a little) on both the pre-comp and the actual data tracks, but
Perstor used a different technique which does not use the higher frequency on
the data tracks and is generally as gentle to your drive as a WD control card.
I have seen very little press about this board but I know that many BBS
people are enthusiastic about this product. The 8 bit card takes up an
extra slot on your machine and can control two hard disks (they can be different
types). The sixteen bit cards REPLACE your WD control card and handle 2 floppies
as well as two hard disks (and I have heard that it might be possible to run
two of these cards so you could have 4 hard disks and 4 floppies!)
I am awaiting this new card which has been delayed in shipping since it is a
first run edition. When I called last, the cards were back from Taiwon or where-
ever they were being printed, and they were being popualated here and will ship
around June 1. I will run it through its paces in my Dell SYSTEM 310 and try to report to the net how it works.   

I am not into advertising for Perstor, but I do like the idea of inovation and
this product seemed interesting to me. I do a lot of desktop publishing and
need all the space I can get (I have almost 30 Meg of soft fonts!) as do most
other heavy computer users I know. This will not give the performance of an
ESDI drive since the access time is not increased, but a high data transfer
rate is very useful if you are reading many contiguous files (such as soft fonts
, image files etc which DTP people use). The price of a 4096 w/ this card gives
150Meg at about half the price of the ESDI equivalent. You can't fight the 28ms
access time, but the high data transfer rate is appealing.  
The data is place in 31 sectors instead of the standard 17 sectors used by MFM.