The more recent history of DR GEM

Thu, 18 Sep 2025 16:19:54 GMT

A tech blogger called Nemanja Trifunovic posted an enjoyable article called the History of the GEM Desktop Environment.

It's a nice piece -- it's very good on the early history.

It does, however, totally omit much of the later development.

When Caldera released the source code, it also released the unfinished multitasking GEM/XM version.

Another version was X/GEM on FlexOS [PDF], DR's multitasking RTOS line, and at least some forms of UNIX.

DR FlexOS eventually evolved into IBM 4680 OS.

And that evolved into IBM 4690 OS, later sold as Toshiba 4690 OS.

This supports a GUI, which I think is based on X/GEM -- as well as TCP/IP networking, app development in Java, and more. It was sold until about 10 years ago.

I don't think I've ever seen a screenshot.

There have also been interesting later FOSS developments.

On the ST platform, TOS + GEM evolved in multiple directions. Some were proprietary, such as MagiC.

A FOSS one became MiNT, which is sometimes called FreeMINT.

This became the basis of TOS 4, so "Mint is Not TOS" was redefined to mean Mint is Now TOS.

There's a complete distro of FreeMINT with the TeraDesk multitasking desktop, called AFROS. It targets a FOSS ST emulator called ARANyM.

One version is on Github.

Some very minimal firmware to emulate just enough of TOS to boot the MINT replacement OS was developed, called EmuTOS.

This eventually grew into a very complete FOSS clone of TOS+GEM. It even supports some Amiga hardware now!

There's a 4min demo on Youtube.

EmuTOS went from a stub ROM that just reproduced something analogous to the kernel of MS-DOS to a full graphical OS, using the PC GEM source code that Caldera made GPL.

So there is a lovely full circle here, where the ST version continued for years after Windows killed off the PC version, but then the PC version got open-sourced and was used to revive and modernise the ST version in the 21st century.

There's been a lot more GEM-related development in the last decade or two than you'd expect. This makes me happy.

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Liam on Linux

The more recent history of DR GEM