RE: CBM 8280

From: COPLIN, Nicholas. (
Date: 1999-08-27 02:27:50

along similar lines to this thought, it could be an issue similar to that
with 1581 disks, but more correctly: the issue is magnetic flux density,
etc. or even more correctly "oersted of magnetic coercivity".

lower density disks have lower values, and higher density disks higher
values.  I don't specifically know anything about the 8280, but the ability
to write is heirachial: if it is SD (single density) then only SD disk will
do. if it is DD, then SD or DD disks will work, but the SD disks may not be
readable in another SD only drive, etc for HD....  You can tell if its SS or
DS by checking the heads, but at worst case you'll only have a half formated
disk.... (did the 8inch disk you have say "SSSD of DSDD, ... if they are
pre-formatted and of higher density than the drive you may not generate the
"oerstads" to overwrite

By the way: 1581 are spec'ed as DD, some will read/write HD, but these are
probably drives on the fringe of production tolerances....
- Nick

> -----Original Message-----
> From:	Howard Herman []
> Sent:	Friday, 27 August 1999 2:48
> To:
> Subject:	Re: CBM 8280
> Bo Zimmerman wrote:
> >
> > I opened the pack of
> > 3M SS DD 8" disks I got off eBay and tried to format one.  
>         ^^
> Taking a guess, and this is only a guess, its the DD that's the prob.
> I suspect that DD didn't appear until much later.  In other words, the
> drive probably wants SD disks.
> If my guess is correct, this would not be unlike the prob with the 1581
> drive, and trying to use HD disks, instead of DD.
> -- 
>                     ___  ___  ___      ___  ___
>                    / //_/ // / //     / //_/ //
> Howard Herman     / ___  // / //___  / ___  //
>    /_// /_// /_____// /_// /_//
> -
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