[Coco] Floppy drive controller questions

Arthur Flexser flexser at fiu.edu
Fri Apr 6 23:06:16 EDT 2018

I'm afraid the HDS controller, unlike some made by Disto, does not have the
capability of switching ROMs via a poke.  You'd either have to open the
case and move a jumper, or install an external switcher yourself.

The jumper settings on the HDS are as follows:

The ABC jumper selects between ROM sockets A (24 pin) and B (28
pin)--AB=socket A; BC=socket B.

The other 2 jumpers affect the 28-pin socket B, which may be set to accept
either a 28-pin ROM or a 24-pin one (by leaving pins 1, 2, 27, and 28 with
nothing plugged into them).  The DEFGH jumper handles that:  Connect EF
and GH for 28 pin operation, DE and FG for 24.  Under 28-pin operation,
IJK selects ROM capacity: IJ for a 2764, JK for a 27128.


(I have an uneasy feeling I may have gotten the pin numbers to be left
empty wrong when using a 24-pin EPROM in the 28-pin socket.  It might be 1
and 28 at one end and 14 and 15 at the other end.)

On Fri, Apr 6, 2018 at 8:48 PM, rietveld rietveld <rietveldh at hotmail.com>

> Hi. I have a dual DOS floppy controller by Hard Drive Specialist. How do I
> select which DOS I want to use (RSDOS/ADOS3)?    Is it software selected or
> do I need to open the case every time and move a jumper?
> Sent from my BlackBerry Passport Red Edition.
> --
> Coco mailing list
> Coco at maltedmedia.com
> https://pairlist5.pair.net/mailman/listinfo/coco

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