The Common Desktop Environment lives again.
I realize that I write about obscure topics and this is probably on that end of the spectrum. I collect old Unix computers and a few years ago I was super excited when The Open Group released the source code for CDE. The reason for this post is that I found a great Slack Build that mostly works out of the box. With a clean install of Slackware Linux, I was able to install the build and with a little bit of tweaking get it to run. You have to make some serious security compromises for this installation so don't use it for anything critical. It is basically just an historic artifact at this point but one that is worth preserving. Considering that many old Unix platforms used RISC processors, it isn't possible to run them in a VM and emulating them is difficult. (If they were I wouldn't have to keep buying SGI workstations!) Given those constraints, this is probably the easiest way to play with CDE on a normal computer.
CDE was the de facto interface for old Unix systems. Solaris. Open VMS. HP-UX. Tru64. And a bunch of others. It also inspired many other interfaces such as 4DWM used by SGI's IRIX operating system and was a huge influence on the NextOS.
The brief explanation is that CDE is a window manager, toolkit, and set of widgets for the X Window system. It provides a consistent interface across different operating systems to simplify the user experience. More importantly, it makes porting software between Unix workstations easier.