Date   : Sat, 16 Jul 2005 15:41:58 +0100
From   : "BeebMaster" <beebmaster@...>
Subject: Re: floppy discs

Yes, you definitely have an 8271 interface in your Beeb.  If it was a
1770, you would have "Acorn 1770 DFS" in the start-up message and
*HELP would report a version of DFS greater than 2.00.  You would also
probably have "SRAM" showing up in the help message as well.

By the way, if you're interested, the "P" before 8271 on the chip means
it is a Plastic one.  Some of the early ones (usually (C) 1977) are ceramic
and are D8271.


Best wishes,


Ian

----- Original Message -----
From: Colin
To:  <bbc-micro@...>
Sent: Sat, 16 Jul 2005 15:12:43 +0100
Subject: Re: [BBC-Micro] floppy discs

BeebMaster wrote:

> By the way, it doesn't work in 1770 DFS (I think it is a different format
> control code for the 1770 series).

Then Andrew Benham wrote

>The 8271 floppy disk controller has a "format track" >command, so the
>software to format the disk has to call this command 40 or >80 times.

I have looked inside and there is a chip with a sticker on marked DFS 1.2
(in IC100)  and the markings on the chip say ST (logo) 88938 M27128AF1 P8M
12.5v (which is the same as for the "Word Wise"  Rom next to it (in IC88)
which, according to what I read on the site below, are not the right places
(although the previous owner said everything was working up to the day she
got a PC and retired the Beeb). Looking at the circuits at
http://owl.8bs.com it would appear that I have a BBC B and I have found the
chip for the FDC whch says P8271 L54501-10 c.Intel '78. (The chip is in
IC78).
Does this help?
Colin Hill