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From: cabr07@vaxa.strath.ac.uk
Newsgroups: comp.sys.acorn
Subject: Re: BBC disc drives..
Message-ID: <1991Mar15.102426.10477@vaxa.strath.ac.uk>
Date: 15 Mar 91 10:24:25 GMT
References: <1991Mar12.024637.12084@monu6.cc.monash.edu.au>
Followup-To: comp.sys.acorn
Lines: 42

In article <1991Mar12.024637.12084@monu6.cc.monash.edu.au>, vac122g@monu6.cc.monash.edu.au (Daniel Bowen) writes:

> The disc drive on my prehistoric BBC B has bitten the dust.. so, I
> need a new one. But it has to, of course, be the same format as the
> old one so I can read my zillions of discs!
> 
>    - Acorn Disc Filing System 1.2, Single density, 80 tracks based on
>           a very ancient 8271 disc controller.
>    - 80 track drive, double sided, running on single density.
> 
> Now, the clincher is this. Can I use a standard IBM-PC 1.2Mb drive? (Which
> will be a great deal cheaper than having to order a special drive from
> the UK, as Beeb distributors here are as rare as hen's teeth)
> 
> My logic says yes. A 1.2Mb drive is a double-sided, 80 track
> drive running under quadruple density; am I right?

Yes but an 8271 can handle only single density drives.
 
> Where as I want a double-sided 80 track drive running under single
> density; okay? But, the density is dependent on the disc controller,
> is it not? That way on a PC a 1.2 can impersonate a 360... (which
> would be a 40 track double sided, double density). But as I still
> want 80 tracks, I should have none of those problems about disc
> head width or whatever.

An 8271 will handle a 720k IBM type drive with the right connector BUT you 
need a newer type of controller if you want to attach a quad density (1.2M)
drive.

> Daniel Bowen


Gordon.
-- 
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