Xref: utzoo comp.sys.ibm.pc:16509 comp.periphs:1024
Path: utzoo!attcan!uunet!husc6!mailrus!ames!oliveb!pyramid!octopus!pete
From: pete@octopus.UUCP (Pete Holzmann)
Newsgroups: comp.sys.ibm.pc,comp.periphs
Subject: Re: TECHNICAL DETAILS: Perstor RLL controllers
Summary: More stuff...
Message-ID: <254@octopus.UUCP>
Date: 18 Jun 88 14:28:06 GMT
References: <243@octopus.UUCP> <288@bby-bc.UUCP>
Reply-To: pete@octopus.UUCP (Pete Holzmann)
Organization: Octopus Enterprises, Cupertino CA
Lines: 48

In article <288@bby-bc.UUCP> john@bby-bc.UUCP (john) writes:
>In article <243@octopus.UUCP>, pete@octopus.UUCP (Pete Holzmann) writes:
>There seem to be two classes of Perstor controller according to your
>article; is one obselete now?

There *are* two classes. The first one is hardly obsolete; I can't even
find one to buy yet! In fact, only the hard-disk-only versions of the
first controller (1.9X) are available now. Hard+floppy and the new 2.0X
version are supposed to be available later this summer. I'm sorry if I
am spending too much time talking about vaporware.

I doubt that the higher density type will replace the lower density one in
the market. The lower density type works with most existing MFM and RLL
drives. The higher density one will only work with the best of existing
drives.

>In their ads the controller seems to be a pc/xt type - do they have
>a 16 bit at controller?

They have both 8 and 16 bit bus versions.

>What does the controller look like to the operating system - does it
>pretend to have twice as many tracks (or heads) or does software have
>to know there are up to 34 sectors/track?  I realize they probably
>provide software for dos but it would be real nice to be able to
>drop it into an AT unix box and have work (I know - probably too much
>to hope for).

As far as I can tell, they do what most
high-density-drive/controller folks do. They design for DOS. Under DOS,
the first sector (?) on the drive contains a parameter block listing things
like heads, sector size, sectors per track, etc. Their low-level format
routine would set things up to look this way.

I know little about Unix/Xenix on AT's. If *nix looks at the disk parameter
block to figure everything out, you ought to be in good shape. 

>Thanks for another good article.

You're welcome!

Pete

-- 
  OOO   __| ___      Peter Holzmann, Octopus Enterprises
 OOOOOOO___/ _______ USPS: 19611 La Mar Court, Cupertino, CA 95014
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