SD Card disk drive for C-64?
mhs.stein at gmail.com
Sat Jan 23 23:53:32 CST 2016
----- 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?
> On 1/23/2016 8:58 PM, Eric Christopherson wrote:
>> On Sat, Jan 23, 2016, Jim Brain wrote:
>>> 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.
> 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.
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:
More information about the cctalk