So, by way of searching for something about which very little exists on-line due to it having died in the early 90s, I looked at the PRIMOS Wikipedia entry http://en.wikipedia.org/wiki/PRIMOS
It seems fairly accurate - my first job was on Primes. The main difference I remember was that it used @ where DEC and everyone who was influenced by it (Unix and Digital Research and hence DOS / Windows) used * i.e. all versions of all files was @.@;@ not *.*;* (how we laughed). "The article says Late versions of PRIMOS included a scripting language, CPL (Command Processing Language) that ESRI used as a basis for its platform-independent scripting languages AML (for ArcInfo) and SML (PC-ARC/INFO)." Indeed, I spent a couple or so weeks writing things in CPL to control / list batch queues of time consuming image processing things. CPL was a proper block structured language, much more of a 'normal' language than DCL, the Unix shell scripts or DOS batch files from what I remember.
I had no idea about the ESRI connection, though - ESRI's fine GIS being one of the ones our software talks to, it being the market leader. Bizarre.
Even more bizarre, I then searched for Gems Of Cambridge and Gemstone, a long defunct piece of kit that we had connected to the Prime. The company went bust but I assume the kit was horrifically expensive back in the day, as it had powers I didn't see on normal computers in terms of speed of image display, switching between images, zooming, panning, animation etc. for probably a good 10 years afterwards (memory may be slightly wrong here) and found this http://www.tandfonline.com/doi/abs/10.1080/10106048809354187 . This mentions a version that ran on a PC (which I didn't know about, may of course not have really existed) and mentions that it could be linked 'via the Cartographic Suite' to GIS including ARC/INFO (old ESRI product). I suppose I shouldn't be surprised but it seemed weird to me to come across these links I didn't know about.
