Ever since I’d heard that the UniDisk 3.5 has within it a 65C02, I’ve wanted to get my hands on one. Not so I could read 3.5″ floppies, but so I could try to see if I could get any mileage out of doing parallel processing, dumping computing tasks to the disk drive while the computer itself did other things. Details of how this kind of thing can be done are buried in the IIgs Firmware Reference Manual in chapter 7, where one can find details of how to send programs to the drive. In principle, it appears that a SetAddress call (defining where the code will go), DownLoad (sending the code itself), Execute (to set the code in motion), and UniDiskStat (to find out what the result was) should be all that is needed. Since it’s just 65C02 code, too, I could handle that.
Of course, whatever time one gains by letting the drive compute stuff on its own, one trades in the time it takes to get data in and out. The only kind of thing that makes sense for something like this would be some kind of intense computation that doesn’t either need or return a lot of data. My first experiment with this will likely be something like a fractal drawing program.
The problem is, the UniDisk 3.5 is fairly rare. And for some reason, pretty much as soon as I decided I wanted one, the prices of these things on eBay skyrocketed. As I type this, there are three available on US eBay, one for $250, one for $305, and one with a starting bid of $88 (all calculated with shipping to me). I’m no longer able to see some of the completed auctions that I know I remember, but they have actually sold for prices like this too (the only completed one I could find just now was another $88 one). But at least while I was watching, $125-$150, or higher even, was not an unrealistic price to see these sell at. (Particularly if the sale involves the LIRON card you need to connect a pre-GS expandable II to a UniDisk 3.5.)
As I was browsing around with the Google search term A2M2053 (the model number of the UniDisk 3.5), daydreaming of parallel processing, I came across this, on an alternative commerce site called ecrater.
After doing a little bit of research, I’ve come to the conclusion that ecrater is a complete wild west of a marketplace, anyone can get a seller’s account, with very little in place by way of safeguards. Boy did this look too good to be true. Well, apart from the fact that this seller’s feedback score was negative 64%. It was four drives, two of them regular 3.5″ drives, one a 5.25″ drive, and one a UniDisk 3.5, all shipped to me for $47—which is less than any one of those units individually would be capable of fetching on eBay.
I sent a couple of cautious emails to the seller, and when I got what seemed to be sensible (if terse) responses, I decided to gamble. I crossed my fingers, hoped that PayPal’s own dispute resolution might be able to help me out in a pinch, resolved myself to the fact that I didn’t care all that much if I was just throwing away $47, and hit the button.
And then, the drives came!
And for some reason I didn’t take a picture of them that I can include here. But they all arrived, exactly as pictured in the ad, all of the drives look perfectly workable and intact. I cleaned up the UniDisk 3.5 so that it looks presentable, but I’m going to open it up and clean up the inside as well, at which point there will be pictures (and hopefully of fractals it helped to draw as well).
I’m not sure what the moral of this story is. Really, I just acted recklessly, I wouldn’t suggest anyone else do the same, certainly. But, weirdly enough, it all worked out perfectly well. And so now I have the UniDisk 3.5 that I was after, and I got it for essentially $12. It would be great if things like this happened often, but I think this was just a fluke. I have managed to score a couple of pretty outstanding deals even on eBay (at some point in the not so distant future, I’ll perhaps also tell the story of how I came to have two Titan /// plus //(e) board sets, for example), but really I’ve probably just been lucky. Perhaps it can restore a little bit of faith in humanity and the internet that this thing, which, honestly, seemed like it had “scam” plastered all over it, turned out well. Or, maybe, this is just the internet giving me the first one for free, so it can demolish me later once I start to trust it.