[Coco] Tandy Coco hard drive controller

[billg999 at cs.uofs.edu]

> Oh, it existed all right. It was a $129 adaptor for a "real" hard drive
> controller board,

So, it took another board.  Sounds like yet another SASI controller,
I have a pair of OwlWare cartridges that I was sold decades ago as
SCSI controllers that I think are actually SASI and need an additional
controller to do SCSI.  I assume there may have also been SASI to MFM
controllers.  I am thinking of yanking all the chips off these cards
and using them to hold DriveWire PROMs.

>                   compatible with the huge (and hugely expensive) hard
> drives that Radio Shack sold for their other TRS-80's.

All hard disks were expensive in those days. Try looking up the
prices of DEC MFM Disks.

RD52 -- 31 MB  --  $3,300
RD53 -- 71 MB  --  $3,800

And that from 1987.


>                                                       The descriptors for
> it were included on the OS-9 Config disk, I believe, and supported up to a
> 70MB drive (going from memory here),

Nope, 70M was the limit in those days.  Had to with the register size
in the common WD Controller of the era.  I did see projects to put a
different controller into some systems (like the 3B1) late in the life
of MFM  but they never got much larger.  I still have a Tandy 12 Meg
drive from my Model 16.  I considered finding a way to use it on a
Model III or Model 4 but better options are available today.

>                                      with smaller options as well. I don't
> know anybody that used them, though, except I think Steve Bjork did early
> on, as these were very primitive and expensive drives at the time.
>

bill