1981 – Apollo introduced the “Domain” line of computer workstations. Powering these new workstations was the Aegis operating system (later renamed to “Domain/OS”). The user interface was simply named “DM” (aka “Display Manager”). Interestingly, Aegis was a very simple beast... at least from a GUI perspective. The idea is that you really only need these computers for a few purposes... so you could just launch them from the command line when needed.
Randomly Nerdy Anecdote: My first job out of high-school involved repairing these aging Apollo workstations. They were old and dusty, and their cases were getting that “really old computer case” look to them. But getting one of these beauties running again made that 19-year-old nerd feel like Indiana Jones.