23 Jan
2016
23 Jan
'16
9:53 p.m.
----- Original Message -----
From: "Jim Brain" <brain at jbrain.com>
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
Sent: Saturday, January 23, 2016 10:28 PM
Subject: Re: SD Card disk drive for C-64?
The one I saw at the WoC was a 8" drive connected to a PSU and the cable
attached to a small PCB that replaced the editor ROM in the PET. THe
PCB mapped a controller into the address space and the editor ROM was
patched to support a DOS.
It was an interesting setup. Mike N (of 6502.org) had the unit. Steve
Gray on here was there too and could provide more details.
Jim -------------------
I was the third guy at Mike's WoC booth trying to help figure out why it wasn't
working initially; took a while for one of us to notice that the PET we were using was a
different revision than the one Mike used at home and it had to be connected slightly
differently. I also made a cable to try using a 5.25HD drive instead of the 8" but we
(I) didn't have enough time to get that working completely.
The device in question is a CGRS Microtech PEDisk II and just like most systems it has a
boot ROM which provides some low level functions including the loading of a DOS from disk,
which in turn is accessed with a set of 'wedge' commands.
When I asked here recently about cloning a PCB this is the one I had in mind, but
we'll need a schematic anyway sooner or later; Mike's already done a heck of a job
reverse-engineering the software.
More info here:
http://mikenaberezny.com/hardware/pet-cbm/cgrs-microtech-pedisk-ii/
m
On 1/23/2016 8:58 PM, Eric Christopherson wrote:
> On Sat, Jan 23, 2016, Jim Brain wrote:
... snippage
After the PET intro, Peddle designs a drive, a beast
of a device, with 2
CPUs and it costs a fortune. Peddle is convinced a smart drive is best, and
the delay allows other manufactures to create "dumb" drive options (saw one
at World of Commodore, forgot the name).
How did these dumb drives interface with
the computer at a software
level? I'd think a DOS would need to be loaded somehow.