16 May
2023
16 May
'23
8:54 p.m.
Just having the ISA card will probably not be enough unless you can find
an operating system that has drivers for that particular controller
hardware and disk format.
The color computer only had a few floppy formats (Coco, OS/9, Flex/StarDOS).
As for hard disk formats, I have no idea. I ran Flex and OS/9 on 6809
based computers with hard drives but what OS that controller was
designed for I have no idea.
Most of the CoCo floppy formats would probably not apply to even small
hard drives due to limitations of their file structures. For example
Flex only supported 256 tracks and 256 sectors/track with each sector
being 128 bytes (single density) or 256 bytes (double density). That's
a maximum size of 65536 sectors and 16,777,216 bytes. OS/9 could handle
larger drives but I don't remember the format they used.
The ST-251 has 820 Cylinders, 6 heads and 17 Sectors/Track. That's
83,640 sectors or 42,823,680 bytes (512 byte sectors).
Most likely there was some kind of driver for the CoCo that converted
the ST-251 into smaller logical drives for the CoCo Operating system.
In order to get the files off of the drive you will need to understand
the actual high level format of boot sectors, root directory and sub
directories as well as how the format ties sectors together into files.
I'm sorry but I am not familiar with any CoCo OS hard disk formats.
The STS-251 is a 50MB unformatted drive with
On 5/16/2023 3:16 PM, Jim Brain via cctalk wrote:
On 5/16/2023 3:00 PM, Kenneth Gober wrote:
On Mon, May 15, 2023 at 11:21 PM Jim Brain via
cctalk
<cctalk(a)classiccmp.org> wrote:
At the most recent CoCoFEST!, I brought home the old Glenside Club
Computer Hard Drive. The mechanism is an ST-251, and I was
wondering if
someone on-list would be willing to attempt to pull data off the
drive.
In my experience, reading the data from this type of drive is
dramatically simplified if
you have the original controller it was attached to. If you can get
your hands on it, this
job will be many many times easier, and doable without special
equipment.
-ken
I did not know that.
I do have the original controller, but it's a bit complicated.
The controller is a Burke & Burke CoCo HDD controller. I pulled the
PCB from it. Inside is 2 PCBs. One looks like a standard 8 bit ISA
card (WD1002A-WX1, no rev number), and the other is a small PCB that
appears to adapt the ISA bus to the CoCo bus (4 MSI TTL and a CR2032
battery). I assume just having the ISA card would be enough...
Jim