Comment by lproven

> I don't know what happened to GEM.

Choosing to interpret you literally:

Apple sued, and DR had to cripple GEM 2. The Atari ST version was unaffected.

https://www.nytimes.com/1985/10/01/business/digital-research...

https://books.google.im/books?id=w3IudMVoEusC&pg=PA2&redir_e...

Caldera made it GPL in 1999.

https://www.theregister.com/on-prem/1999/04/27/gem-the-gui-t...

The FreeGEM project modernised it and added back not only all the functionality that DR removed, such as overlapping windows and desktop icons and things, but also additional features from the runtime-only GEM/4 and GEM/5, such as Bézier curves and things.

https://www.seasip.info/Gem/History/freegem2.html

OpenGEM was the last distro of FreeGEM getting updates, and it's included in FreeDOS.

https://multiboot-windows.dscloud.me/All_Pages_for_DOS_GUIs/...

Back on the Atari ST, EmuTOS started out as a minimal stub boot ROM for the all-FOSS AFROS replacement OS for the Aranym emulator; over time, EmuTOS evolved into a complete FOSS replacement ROM for the ST line -- and to recreate GEM, they went back to some of those Caldera source files.

https://emutos.sourceforge.io/

As to the bigger more general question of why PC GEM didn't compete...

DR's GUI was originally one element of DR's catalogue. GEM ran on Concurrent DOS, and DR-DOS included a cut-down version that's just a file-manager and app-launcher, called ViewMAX.

https://en.wikipedia.org/wiki/ViewMAX

(The beta version of ViewMAX 3 ended up FOSS too.)

DR had a full multitasking DOS-compatible OS on the 286, something like 4 years before OS/2 1.0. However, it used a feature that Intel removed from the shipping 80286 chip. The shipping PC AT could not multitask DOS apps on Concurrent DOS 286.

So DR pivoted: it turned CDOS 286 into FlexOS, an RTOS that happened to have some DOS compatibility. It turned GEM into X/GEM, a multitasking version that could use the underlying OS's multitasking.

(ViewMax on DR-DOS 6 can manage multitasking full-screen DOS sessions using DR's TaskMAX multitasker.)

FlexOS with X/GEM evolved into many forms, and was sold by Siemens and many other companies, as an embedded control RTOS for all kinds of hardware.

The last ones on sale were for cash registers -- PC-based point-of-sale tills. IBM 4690 OS was still on sale in the 2000s, and it's based on DR FlexOS and X/GEM, with app development in Java that displays in a GUI that was a remote descendant of GEM.

Toshiba still supports it.

https://commerce.toshiba.com/wps/portal/marketing/?urile=wcm...