Msg: 4128 *Conference*

03-21-93 20:55:08

From: RICHARD HANSON

To : LEE KELLEY

Subj: REPLY TO MSG #4124 (CHIPMUNK)

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Sorry to have to say this, Lee, but the Chipmunk drive is not a serial device.
It's a bus device; thus must plug into the system bus.  Here's how it works:

The Chipmunk drive was first invented to run on a Model 100 (not 102 or 200).
It came with an interface card that plugged into the system bus under the
keyboard of the Model 100.  It also came with a new, plastic cover for the
compartment that allowed the special cable (included) to connect into the
interface card, extend along the bottom of the computer, and out the back where
it plugged into the Chipmunk disk drive.

The Chipmunk disk operating system (CDOS) was coded into a ROM on the
controller card in the drive, and activited by an interrupt from the computer's
bus (an interrupt driven bus); via the interface card.  The interrupt was
activated by either pressing RESET on the computer, or going into BASIC and
issuing the command: CALL 0 <enter>.  In other words, you did not need a
separate boot disk to "boot" the DOS into your computer.

After they [Holmes Engineering, and PCSG (the Portable Computer (non)Support
Group] perfected the Chipmunk drive and CDOS for the Model 100, they built a
special unit for the Model 200.  The 200 version had the interface card on the
drive, along with the controller card, ROM, etc.  In this case, a cable went
from the Munk to the system bus on the Model 200; again, an interrupt driven
bus.  In both cases, booting was the same.

As the story goes, along comes the Model 102, and with it, several changes,
internally, including the elimination of "the interrupt" necessary to "boot"
the Munk--actually, they [Tandy] instituted one way buffering on several of the
bus lines for some very good reasons, not associated with the Munk drive; and
of course, Tandy does not do anything with considerations to 3rd party support.
As a result, the sales of Munk's dropped off rather quickly.  When sales
dropped off, so did revenues necessary for continuing the Munk.  Result: bye
bye Chipmunk!  That's all she wrote!!

So, again sir, I state... Do you have an interface card?  No?  Then perhaps
your Munk is for a Model 200... maybe but probably not.  I have an extra spare
interface card and cable.  It's for a Model 100.  I will part with my extra
spare interface card and cable for $50.  This leaves me with one spare card and
cable should I need to use my Munk for any club reason and my original card and
cable dies.  And, indeed, I have an order on my work bench to copy some files
from Munk disks to DOS disks for a guy whoes Munk died.  I have another sitting
here, too, for two library issues on Chipmunk formatted disks--a very rare
activity for me these days.  So, that's the name of that tune.

Hope this helps... -Rick-