Success with ADTpro was surprisingly good

I took a shot at imaging some of my 5.25″ Apple floppies from the mid-80s today, using ADTpro talking to my IIgs over the modem port connected via a Keyspan dual serial adapter (driver here) to the USB port on my MacBook Pro. Two bits of good news to report: it’s actually quite quick, and it seems to be pretty fault-tolerant. ADTpro managed to read about maybe 70% of the disks I gave it without errors on either the front or back sides, which either means that ADTpro is good at retrying read errors, or that the floppies were still in pretty good shape. Many of the errors I encountered were actually ones I remembered, disks that had developed errors back when they were being used. I’m hoping that my Kryoflux, when it arrives, might be able to reconstruct some of those wayward bits as well.

Anyway, I imaged most of my highest priority floppies, mostly source code and experiments, not many of the games that already exist in disk images on the internet somewhere, but I intend to finish this first pass through the rest of them pretty quickly. The Kryoflux is not well suited to imaging the flip side of these disks, so I’m glad that the Apple is able to read most of the flip sides.

Among the things I had that I’m pleased still to have access to (because of how 1337 it makes me) is the source code to Cat-Fur. I forget the specifics now of how I acquired it, but I believe it is The Micron’s actual Cat-Fur 3.1 source code (uncommented, but with enough symbol labels that it probably isn’t just a disassembly of the binary file). I wrote a number of Cat-Fur modifications myself, which perhaps I’ll document here at some point. Cat-Fur was a huge part of my BBSing experience, but oddly it seems to have almost no representation on the internet of today, so if you don’t already know what it was you don’t have a very easy way to find out (it was a modem-specific file transfer program, designed for the special capabilities of the Novation Apple-Cat ][ modem, which had the ability to transfer at 1200 baud, but only half-duplex, so a complex handshake system was needed in order to permit two-way communication.).

Catfur src snip

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  1. Any chance I could get a copy of that source code?

    I haven’t seen it since I got rid of my apple II+ 25 years ago to buy an Amiga. Might be fun to take a look at it again.

    BTW, I’m still guilty of not commenting my code 😉

    The Micron (Keary)

  2. Excellent, glad to have the opportunity to get it back to you. I’m hoping to document some of my own experiences with Cat-Fur once I can actually sort through my old disks. I wrote some kind of interesting patches (one was an Eliza program that you could chat with during transfers, another was a shift-key simulator so you could chat in lowercase on a II+, and I think there were others). But still, very cool to hear from you, and thanks for the big part your program played in the BBS era!

  3. Why wouldn’t the kryoflux work for the flipside of Apple II disks?

    The “flippies” described in:
    .. is for like the twiggies and disks that have two heads reading simultaneously.

    It also says, “Drives with one head only had their disks flipped to read or write the second side. Just flip the disk, and side 1 will appear at head 0 at the correct position.”

    And this is essentially the situation with Apple II. One head, one side. There is no connection with having to have cylinders, tracks, or sectors aligned with respect to each other.

    Each side is an independent disk image. Read side A, make an image. Read side B, make an image.

    • Hi — sorry about the long delay in noticing this comment. The problem with reading the back side of Apple II disks is that a lot of disks only have one index hole window in the sleeve (except for explicitly double-sided disks). When you put the disk in upside down in a PC drive, it can no longer sense the index hole and so it flips out. If you can somehow punch an appropriately positioned hole in the disk casing (but not through the media), you could just flip the disk. Otherwise, you need to modify the hardware to either send a fake index signal or add an extra sensor on the other side. Alternatively, you can modify the drive to allow for use of the other read head but with the ability to position itself below track 0. Both of these issues are actually described in the Kryoflux forum post you linked to.

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