I have a pretty decent collection of retro computers, but I have always been a Commodore and Apple guy. I recently picked up an Atari 800XL and a 1050 disk drive, so I am investigating the methodology for imaging Atari disks.

I have extensive experience with the ADT (Apple Disk Transfer) tool and StarCommander (C64 disk transfer). Both connect to a PC via the serial or parallel port, and I was able to get both working using nothing more than some homebrew cables (and the hard work of the authors of those fantastic programs). I also already had working disks from high school, so I had access to terminal software, DOS, etc...

Is a similar technique for Atari disk imaging available (ie. whip up a cable and download some nifty utility and off you go)? And will my lack of any existing disks impede my attempts? For example, to display my ignorance, did Atari boot DOS from disk? Would I need a bootable disk to get started? Or terminal software and a null modem? Etc.

I realize I have grouped a few discrete questions together here, but what I am driving for is a general overview of the methodology and requirements for imaging Atari disks, including pros/cons and possible "gotchas". Any kick in the right direction is most appreciated.

1 Answer 1


Well, after spending some time googling last night I have discovered something called SIO2PC. This is probably old news to the Atari fans out there, but in case anyone is having the same initial questions I was, I thought I would answer my own question with what I have learned. Please feel free to correct me if I get this wrong, or add more information.

Basically SIO2PC is a small hardware adapter that converts the 0v/+5v TTL signals on the Atari SIO (which I assume stands for serial I/O) port into +/-12v RS232 signals for a PC serial adapter.

Scrounging around the authors web site it appears his solution is to use an 232-max IC and some supporting circuitry. If you have any inclination towards do-it-yourself electronics, this would not be a difficult project. I think the hardest part is going to be figuring out where to source an Atari SIO connector to cannibalize.

After that, you simply load up the software on the PC side, connect the cable/adapter between the Atari SIO and the PC, and the Atari will apparently think it has a disk drive attached.

Also, from what I can gather, this project must have come early enough that it set the de-facto standard for Atari disk images, which are files with a .ATR extension. It looks like most desktop Atari emulators support the .ATR file.

I haven't put any of this to the test (yet) so YMMV. But you can find SIO2PC at this address: http://pages.suddenlink.net/wa5bdu/sio2pc.htm

  • 1
    There are also USB versions of the SIO2PC devices. The free software you want to use with it is AspeQT. There is also a similar commercial product called APE which has more functionality such as plotter and modem emulation. You are correct that ATR is the de-facto standard for Atari disk images, although there are other formats used to image copy protected disks.
    – Tim Locke
    Sep 25, 2016 at 14:08
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    Many modern USB serial adapters or onboard serial interfaces already use TTL levels, so you can avoid the level shifter in this case. Also have a look at the Atari FAQ (SIO2PC is 3.9), and note that it's available for many systems. There also seem to be programs to read/write Atari floppies from the PC.
    – dirkt
    Sep 25, 2016 at 18:40
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    Lotharek (lotharek.pl) can provide connectors if you want to build your own cable. I actually use the GPIO pins on an Raspberry PI with a logic level converter to talk to the ATari.
    – Matt Lacey
    Sep 28, 2016 at 0:54
  • Something you may want to consider. I've had issues with the APE software with Windows 10. From what I remember, it didn't play nicely with my USB to serial conversion and the recommend choice was to buy the USB version of the adapter. Which I didn't want to do since I own three of the RS-232 versions.
    – cbmeeks
    Feb 2, 2017 at 15:11

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