Software Spotlight: Twiggy MacOS

A while back you probably heard about the prototype Macintosh that used a 5.25" "Twiggy" drive, similar to the Lisa 1.

The Twiggy disk images and ROM dumps surfaced on macgui.com recently, so a copy has been added here.

https://winworldpc.com/product/mac-os-0 ... re-release

Twiggy%20MacOS%20-%20Steve%20Sez.jpg

The Macintosh was originally intended to use a custom designed 5.25" floppy drive that was also used on the Lisa. Apple abandoned these drives due to reliability issues. The Macintosh was switched to the 3.5" Sony drive at almost the very last minute, and the Lisa 1s were all upgraded to Lisa 2s.

The disks images are in DiskCopy 4.2 format. They were read with, and would need to be written using, an Apple Lisa 1. Which is only slightly less rare than a Twiggy Mac.

For some reason, the boot sector and file table start about halfway in to the disk. If you remove this excess header (or move it to the end where it belongs) you can actually mount the disk images in an emulator under MacOS.

The applications on the disk will not run under any release version of MacOS. There are resource format differences and probably other differences.

This archive also includes the contents of 4 roms. Reportedly there were actually two twiggy Macs and they had to swap the ROMs (a bank of 4 on each machine) to get the one to work. It is not clear which machine this set of ROMs is from.

The archive includes a modified version of VMac that supposedly partially boot the disks, but it is not clear how far it gets. And since the binary is only for Intel MacOS X, I don't happen to have any way to test that.

Here are some of the icons in this version:
upload_4084.jpg

The disks include a bootable MacWrite disk, a Mac Paint disk. The "New Finder and System Disk" is in Pascal format rather than Mac OS format, and is not bootable or directly readable.

And it includes some extracted files and converted pictures from the disks.

Twiggy%20MacOS%20-%20Drawing.gif

A few interesting things:

The Macintosh system icon has a twiggy sized disk, and this same icon is found on the Mac Guided
Tour.

The "pad" icons suggest they may have planed to use template icons like the Lisa.

These versions do not have the question/information/warning popup dialog icons - it has Steve instead!

A Coke can icon?! I thought they were a Pepsi place. :P

Have a very merry [Corporate sponsored end-of-the-year holiday]!

Comments

  • First!

    I loathe twiggy drives. Remember them on the Lisa? The drive ate my word processor. I have the Lisa (old and broken) somewhere. The disk is stuck in it to this day.

    I wonder what would have happened if they stuck with Steve Sez...
  • Couldn't you easily replace the OS X binary for vmac with the Windows version?
  • If I read the comments on macgui correctly, the VMac binary has some custom code in it that they didn't release. If you try the disks directly in VMac, you won't get very far.
    I loathe twiggy drives. Remember them on the Lisa? The drive ate my word processor. I have the Lisa (old and broken) somewhere. The disk is stuck in it to this day.
    You have an actual Lisa 1? Or do you just have the twiggy drive that was removed from it?
  • Why did Apple think it was a good idea to release two systems that ran very different operating systems? Why didn't the Lisa and Mac use the same OS in the first place? They seem very similar.. could those programs on that disk possibly have been Lisa programs and not Mac programs?
  • Why did Apple think it was a good idea to release two systems that ran very different operating systems?
    That was the standard way things were done back then. When developing a new system or model in a line of systems, backwards compatiblity was rarely considered.

    Ironically it was around late 1983, when this was released, that vendors really started to wake up and realize that the market had had enough of this sort of thing. Customers were beginning to vote with their money and drop other architectures for IBM PCs and the new clones.

    And I assure you, underneath the hood the Lisa and Macintosh were very much different. The Lisa was a more powerful, expandable system that had a memory management unit, supported an internal hard drive, and could even run a port of Microsoft Xenix. Running MacWorks on a Lisa really dumbed it down quite a bit.

    The Lisa OS, despite above-the-hood similarities, was also completely different. It was largely written in Pascal, had a full office suite, and the Xerox Alto/Star influence was much more obvious.

    The MacOS was mostly written in assembler in order to fit it in to the Macintosh's puny, non upgradeable, 128k of ram.
  • SomeGuy wrote:
    Why did Apple think it was a good idea to release two systems that ran very different operating systems?
    That was the standard way things were done back then. When developing a new system or model in a line of systems, backwards compatiblity was rarely considered.

    Ironically it was around late 1983, when this was released, that vendors really started to wake up and realize that the market had had enough of this sort of thing. Customers were beginning to vote with their money and drop other architectures for IBM PCs and the new clones.

    And I assure you, underneath the hood the Lisa and Macintosh were very much different. The Lisa was a more powerful, expandable system that had a memory management unit, supported an internal hard drive, and could even run a port of Microsoft Xenix. Running MacWorks on a Lisa really dumbed it down quite a bit.

    The Lisa OS, despite above-the-hood similarities, was also completely different. It was largely written in Pascal, had a full office suite, and the Xerox Alto/Star influence was much more obvious.

    The MacOS was mostly written in assembler in order to fit it in to the Macintosh's puny, non upgradeable, 128k of ram.

    It, wast the case. Diagnostic Port, there was someone sneaky bastards.
  • Incidentally, someone rebuilt the customized version of VMac for Windows: http://www.mediafire.com/download/ju30s ... wigwin.rar
    It gets as far as the desktop, but launching most of the applications crashes it.
  • SomeGuy wrote:
    You have an actual Lisa 1? Or do you just have the twiggy drive that was removed from it?
    An actual Lisa 1. It's pretty broken up though.

    Is it worth restoring?
  • SomeGuy wrote:
    You have an actual Lisa 1? Or do you just have the twiggy drive that was removed from it?
    An actual Lisa 1. It's pretty broken up though.

    Is it worth restoring?

    probably, but you should really ask the guys at Vintage Computer forums: http://www.vintage-computer.com/vcforum/
  • There are a number of Lisa owners at the Vintage Computing forum. (Dont know if any have Lisa 1s) They could point you in the direction of what how to test and what repairs might be needed.

    A Lisa 1 is certainly worth restoring, if possible.
  • Why did Apple think it was a good idea to release two systems that ran very different operating systems? Why didn't the Lisa and Mac use the same OS in the first place? They seem very similar.. could those programs on that disk possibly have been Lisa programs and not Mac programs?

    I think they released the later Lisa's rebranded as Macintosh XL. It ran *mostly* the same operating system as a regular Macintosh, except the screen was weird because they still used the Macintosh resolution. I don't think they did a version for the Twiggy Lisa's...
  • TheXPMick wrote:
    I think they released the later Lisa's rebranded as Macintosh XL.
    You're right.
  • Also, two "Sony Test" 3.5" pre-releases surfaced. One of which contained an earlier Finder prototype (that the developers aparently renamed to "Flounder").

    Those have been added to the pre-release page.
  • edited December 2018
    Nathan LineBack has posted a page about the Twiggy Mac OS in his GUI Gallery. It also has the SONY Test images.

    http://toastytech.com/guis/twiggy.html

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