Use DuoDisk Drive With More Modern Computer

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I have a DuoDisk drive that I would like to interface with a newer computer. I have an iMac G3 running OS 9.2.2 and a Windows PC running Windows 7 Professional x64; I also have some older IBM-compatibles, but I would have to get them working. I have a USB port replicator for serial a parallel interface (I haven't tested it with the Mac yet though). I would like to know if it would be possible to interface the DuoDisk drive with one of these machines.

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Re: Use DuoDisk Drive With More Modern Computer

Quote:

I would like to know if it would be possible to interface the DuoDisk drive with one of these machines.

Nope.

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Re: Use DuoDisk Drive With More Modern Computer

sfahey wrote:
Quote:

I would like to know if it would be possible to interface the DuoDisk drive with one of these machines.

Nope.

For what reason? Would it not be possible to rewire the connection from the disk drive to a serial connection and write or find a driver for it?

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Re: Use DuoDisk Drive With More Modern Computer

Well, yeah, technically. If I were going to do it I'd probably try to use an Arduino or Raspberry Pi as an intermediate controller. The I/O from the DuoDisk is parallel, so you'd need some sort of serial<->parallel conversion between the drive and your controller; and you'd need to write a fair amount of protocol conversion code to map the cylinder, track, and sectors of the old floppies to whatever you were doing on the modern computer. And remember on these old drives, there were no microcontrollers: you're going to have to manage things like pulses to the head positioning stepper your own self.

So, technically, it's possible...think of various products like the CFFA3000 or that ProFile emulator (of course they're going in the opposite direction, enabling the use of modern flash memory with older machines). But it's a LOT of work, and I'm not sure for what.

Oh, and don't forget, if you want to read and write old existing disks, you need to duplicate the file handling routines in DOS, SOS, and whatever other old OSes you want.

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Re: Use DuoDisk Drive With More Modern Computer

dramsey wrote:

Well, yeah, technically. If I were going to do it I'd probably try to use an Arduino or Raspberry Pi as an intermediate controller. The I/O from the DuoDisk is parallel, so you'd need some sort of serial<->parallel conversion between the drive and your controller; and you'd need to write a fair amount of protocol conversion code to map the cylinder, track, and sectors of the old floppies to whatever you were doing on the modern computer. And remember on these old drives, there were no microcontrollers: you're going to have to manage things like pulses to the head positioning stepper your own self.

So, technically, it's possible...think of various products like the CFFA3000 or that ProFile emulator (of course they're going in the opposite direction, enabling the use of modern flash memory with older machines). But it's a LOT of work, and I'm not sure for what.

Oh, and don't forget, if you want to read and write old existing disks, you need to duplicate the file handling routines in DOS, SOS, and whatever other old OSes you want.

Thanks for the information. And in regard to the parallel to serial conversion, I had mistakenly thought that it used a serial connection, so I should ask about wiring to a 25-pin parallel connector. Also, how did the controller card interface with the drive? Are there any drivers that older versions of Mac OS can use to interface with the drive, or would I still have the problems that you mentioned above?

P.S. I'm not entirely sure what the proper way to approach this is, so if you think that I may want to go in a different direction, that I would ask that you advise me on what type of information that I sould be asking for.

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Re: Use DuoDisk Drive With More Modern Computer

The information I posted was just off-the-top-of-my-head stuff; I wrote hard disk drivers for the Apple ][ and /// back in the day, and the day was a very long time ago.

I have no other information to give: I don't know the details of the hardware of the drives; and apparently some of what I remember is wrong, as a few seconds' search popped up this Wikipedia article:

http://en.wikipedia.org/wiki/Disk_II

...which shows that the data from the drive is in fact serial.

But really, you're on your own here. I can't see why you'd spend time doing this, but good luck.

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Re: Use DuoDisk Drive With More Modern Computer

Mike Willegal built one for the PC.
http://www.willegal.net/appleii/appleii-disk-int.htm

Alex Freed reproduced the Disk II controller. His source code may be helpful to you in how it controls the Disk II Drive.
http://alexfreed.com/FPGApple/pseudodisk.html

Chapter 9 of "Understanding the Apple IIe" by Jim Sather has a very good description of the Disk II operation.
https://archive.org/details/Understanding_the_Apple_IIe

Good Luck.

Alex.

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Re: Use DuoDisk Drive With More Modern Computer

To cut to the chase, if it's not clear already:

There's no off-the-shelf dongle you can buy that will do this job for you. The Apple II floppy interface is unique from an electrical and functional point of view; it's not even the same as the standard Shugart interface used by the majority of old computers (including IBM PCs.) You can't just cut wires and jiggle them around to fit a standard serial dongle or parallel printer port; it's *serial* in the sense that what's recorded by the read/write head is carried by a single wire, but by the same standard the 8-Track player in your 1977 Toyota is also serial. To drive it you'll need a controller and nobody makes one you can just *buy*.

The Apple II controller *is* fairly simple electrically but it's also a sophisticated state machine that works in very close concert with the 6502 CPU in the Apple II to do its job. It'd certainly be possible to drive the device using a *fairly simple* dedicated microcontroller but it's not a trivial task. (Keep in mind this person has produced complete Apple 1 and Apple II replica kits.) Are you looking for an advanced electronics project, or are you hoping this will be plug and play somehow?

To back up a few steps, what do you want to use the drive *for*? It only stores 140k per disk so really the only possible use for it would be to read old Apple II disks without actually having access to an Apple II. There is an off-the-shelf product for that, but note that it actually does its magic using a PC floppy drive. It's not compatible with a DuoDisk. A far more practical (and probably cheaper) solution is to hook the drive to a IIe and use ADTPro and a serial cable for your disk transfer needs.