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Thread: Commodore "Winchester Drives"

  1. #1
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    Default Commodore "Winchester Drives"

    Hi, this is my first post.

    I've recently taken the step from "theoretical" to "practical" vintage computing, i.e. actually obtaining some hardware.

    I'm recreating a set-up from the mid-80s, which featured a Pet 8096-SK (which I've almost secured, if I win the bidding).

    As far as I can remember (it 35 years ago), there was a hard drive attached, in the day called "winchester drive". After some
    research, it might have been a D9090, as it was said to have a capacity of 10 MB (mind blown in '83-84).

    It seems somewhat rare - is that a correct impression? Can anyone share any tips on how or where to obtain one, and whether it will cost me an arm or not?

    /Thorbjörn

  2. #2
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    So far as I'm aware Commodore made two PET compatible hard drives, the 9060, which held 5MB, and the 9090, which was 7.5MB.

    Both drives are rare as hen's teeth today, and you're going to have a heck of a time finding a working one because Winchester drive mechanisms from that era are dying like flies, alas.

    There were third-party hard drives for Commodores, I think CMD made IEEE-488 versions, among others, but they're also pretty rare.
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  3. #3
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    The Commodore PET uses the IEEE-488 port to connect to 5.25" floppy or hard drives, and as Eudi has said they are rare and not that reliable. See models 4040, 8050, and 8250 for floppy models as well as the hard drives mentioned.
    Make sure the seller states that the drive is in working order or do not buy as they are difficult to repair. Also shipping these big heavy boxes is expensive and if not well packaged, they will arrive non functional.

    While waiting to procure a real drive, checkout IEEE-488 drive emulators. There were several available from good developers like Tynemouth in Great Britain and Bitfixer.com, but they seem to be out of stock at the moment.

    One called PETsd+may be obtained at: http://www.primrosebank.net/computer.../pet_petsd.htm. It uses SD memory chips for storage. I have one and it works great.
    -Dave

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    One thing that didn't help the survival of these things is the use of cheap Tandon TM602 and TM603 MFM drives. The controller boards, although very slow, might still be found--it was a bizarre setup: an MFM (ST506 interface) drive, an ST506-to-SASI converter, and a CBM-made "DOS" board to convert the SASI signalling to IEEE-488.

  5. #5
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    Hi Chuck,
    Yes, and if that wasn't enough, the floppy drives used a dual CPU design having a common data bus to share RAM memory. A 6502 was used for the IEEE communication and a simpler 6504 used to interface with the disk drive electronics. The RAM was used on a non-interference basis by each CPU using the opposite phase of the 1 MHz clock. They are fairly hard to troubleshoot. This 'smart' peripheral had more computing horsepower than the Commodore PET itself.

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    Has anyone interfaced a real HP IEEE-488 disk or tape to the C64? Say, a HP 7914--or is the C64 variant not close enough to HP?

  7. #7
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    Quote Originally Posted by Chuck(G) View Post
    Has anyone interfaced a real HP IEEE-488 disk or tape to the C64? Say, a HP 7914--or is the C64 variant not close enough to HP?
    It's probably theoretically possible to do it at an electrical level, apparently HP-IB plotters are literally plug-and-play on a PET, but... I dunno, looking at this page about the Amigo command set and how it apparently takes some liberties with IEEE-488 conventions makes me wonder if it's possible there could be a protocol level gotchya. Sounds like some PC IEEE-488 interface cards don't like them.

    It also looks like the HP drives basically just present a block interface to the disk, so you'd have to write a DOS that ran on the Commodore machine. Which presumably you'd have to burn into a ROM or load from cassette...
    My Retro-computing YouTube Channel (updates... eventually?): Paleozoic PCs

  8. #8
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    Yeah, there's the business of protocol. I've got a Shugart SA4006 drive with a GPIB controller that has the same footprint as the drive. (let that sink in!) I haven't run it in decades and don't know if the thing would even work. I'd have to suss out the protocol--too much work for me.

  9. #9

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    Quote Originally Posted by Chuck(G) View Post
    The controller boards, ....., an ST506-to-SASI converter, .....
    I once had the chance to repair FIVE 9060s, no kidding. The idea was to repair as may as possible by taking the good parts. What I got in the end was five broken HDDs, one working ST506-to-SASI converter and three working DOS boards. The really big problem was this controller board: it has parts on it I simply don't know what they are, the ones I knew were nowhere to be found and I only found a vague schematic. So at the end I only had one working 9060. FYI: I replaced the HDD with a 20 MB IBM one, the system hadn't any problems with it. But I could only format it with 5 MB because it only had four heads, for 7.5 MB I needed a HDD with six heads.

    What did I get from it: two broken systems. I was able to repair one of the DOS boards. But having no working controller, I used the case for my own HDD system. See the pictures at the bottom of the page. FYI: the various parts have been glued, no drilling or whatever has been done.

    The second system I gave away to a friend.
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  10. #10
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    As a bit of a contrast, I have a D9090 and a D9060 still working with original hard drives as of about three weeks ago. I need to qualify that because they could go at any time but they run smooth so unless stiction sets in, they might be okay for a while longer. The D9090 is originally from a Commodore dealer here in Canada and remains with the original files. The D9060 needed to be formatted to work again.

    I also have another D9060 that needs work. The original drive could not be formatted but I later found it did not work at all so I need to do some troubleshooting at some point.

    Great drives but the lack of directory support was always a bit of a pain if you were looking for a file

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