Re: Did Commodore cheat with the quad density floppies?

From: Mia Magnusson <mia_at_plea.se>
Date: Thu, 10 Jan 2019 21:13:29 +0100
Message-ID: <20190110211329.00000572@plea.se>
Den Wed, 9 Jan 2019 14:00:09 +0000 skrev smf <smf@null.net>:
> 
> On 09/01/2019 06:38, Gerrit Heitsch wrote:
> > Uhm, the WD1003 is the 16Bit-Controller as used in the IBM AT and 
> > controlled by its BIOS.
> >
> I think I got confused with the WD1002.

Most likely.

A side track anecdote, and evidence that the WD1003 has the same
command set as the IDE drives:

In the late 90's, a friend started building a prototype of an Amiga
expansion board, with the intention to have some better UART. When it
ended up at my place for testing in my A4000 (my friend had an A3000
and wanted to check for any compatibility problems) somehow an ISA slot
and some buffers ended up on the prototype, and I actually had an
WD1003 compatible card and some old MFM drive working.

There were never any production run of that expansion card, probably
because I did feature creep it while my friend tried to keep up with
the changes :) At the time, it would probably had made sense to make
the card similar to the Golden Gate bridge card, but maybe with room
for some boot ROM and with a pass-through ISA slot for the then popular
small multi-I/O cards with IDE, floppy, 2 16550 serial ports, a
parallell port and sometimes a game port.


I used the same code with an experimental IDE controller soldered
directly on a 68000 CPU in an A500. (That however didn't work that
well, probably because I used the super slow 74C00 IC's I had in my
stash and I also used one of the slowest IDE drives. The drive did
sometimes miss that a read were made, which ended up in sectors looking
like they were larger than 512 bytes, so the driver had to re-read the
same sector again. This was btw at a time when it was hard to get any
information of how the IDE interface in A600/A1200/A4000 did work, and
thus this hardware probably didn't use the same addresses).

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Received on 2019-01-10 22:00:56

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