I got BMOW's floppy emulator and have been pulling a bunch of files from 30 year old floppies (which have a miraculously low rate of failure) onto my SD card. One of the things I wanted to copy was a piece of software a friend and I made in high school. I was unable to copy it in Finder, which says "that cannot be duplicated or copied." When I did get a copy of the application off the disk, it wouldn't run without the original floppy disk inserted! I'm sure we thought we were very clever. Anyway, next attempt was going to be a disk image that I can run in an emulator.

But I'm having trouble creating disk image on my Mac Plus with 1 MB of memory. Disk Copy 4.2 tells me "there is not enough available memory" to image an 800 kB disk. I've been unable to find any other software that will run on the Plus, let alone make a successful image.

Are there any tools for imaging a floppy that will run on a 1 MB Mac Plus with System 6?

  • 1
    I assume you have already tried to minimize the memory footprint of System 6? Don't use MultiFinder, remove any extra fonts, DAs, Inits, etc.
    – Glen Yates
    Dec 14, 2018 at 18:09
  • I disabled MultiFinder and removed a bunch of INITs and stuff. But I haven’t gone so far as to start removing fonts. DAs are already pretty minimal but I’ll take a look.
    – miken32
    Dec 14, 2018 at 18:31
  • Oh, well, you could add more RAM, I've probably got some 1meg 30pin SIMMs laying around somewhere.
    – Glen Yates
    Dec 14, 2018 at 18:48
  • Ok, I do have 4 1meg 30pin SIMMs, they are yours if you want them. I can mail them to you, not sure how you should share your contact info though.
    – Glen Yates
    Dec 17, 2018 at 19:53
  • 1
    Sorry, the package must have been mislabeled, well, at least 2 MB is more than the 1 MB you had before.
    – Glen Yates
    May 31, 2019 at 19:27

2 Answers 2


I recommend trying Copy II Mac, but not to make a disk image. Rather, use it to successfully copy your original floppy disk to the floppy emulator/drive. You may even be able to use it to edit the sectors of the original floppy and undo whatever cleverness your younger self added.

Like most other System 6 MacOS software, Copy II Mac can be found on the Mac Garden. The link also lists a handful of other disk duplicating tools that might be useful. Of which DART is especially interesting. It can work with ~200K of RAM to create an image file, if you really don't want to rely on the floppy emulator doing that for you.

  • Excellent idea; I've been using it in HD20 mode, I should have thought to use it as a floppy!
    – miken32
    Dec 14, 2018 at 22:53
  • Bah, doing a "bit copy" gives me a write error showing on the floppy emu about halfway through the first write cycle, "sector copy" gives me an immediate system error!
    – miken32
    Dec 14, 2018 at 23:23
  • @miken32 I think sector copy is what you want. There are many versions of Copy II Mac. Be sure you have something appropriate for your version of MacOS. Also check that the Floppy Emu is properly mounting a formatted disk image of the correct size (800k). If you can copy files to the Floppy Emu using the Finder then you are on the right track. And you still have DART as a possibility too.
    – Brian H
    Dec 15, 2018 at 18:33

IIRC, the way I did this a couple decades ago was to write a bit of 68000 assembly language code that called the RWTS (read-write-track-sector) routine in the Mac ROM. If you could boot a Mac OS System, there was also a low-level OS routine that could be called (documented in Inside Mac?). Then I would poke those bytes in from Basic (or perhaps Forth?) and call RWTS. Bytes from each diskette sector could then be retrieved and sent out the serial port (with a checksum?) to whatever was trying to record what was on the diskette (a newer Mac with no diskette drive), sector by sector, track by track. This works to perhaps recover some partial data even if the diskette directory is damaged.

  • The disk is fine, the problems copying the file were the result of a couple of kids being clever and copy protecting their silly software!
    – miken32
    Dec 15, 2018 at 0:35

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