George was a great manager to work for, too... he's the one who taught me the phrase "It's better to ask for forgiveness than permission". Back in his Cray days, he was told to write a single-pass linker for arbitrary theoretical reasons by the architects. He went ahead and wrote a double-pass linker anyway, because he felt it was the Right Thing To Do. Later, customers praised the stability and debugability of Cray Unix, relative to other Unix of the era (old SunOS == suXX0r), so his "forgiveness rather than permission" paid off.
I actually worked with a whole crew of ex-Cray people in the late '90s, after Silicon Graphics bought them out and started running them into the ground. Smartest team I've ever worked with.
Old web pages suffer from a similar fate. The fast pace of technological advancement make things difficult but we really should be doing more.
The answer is different for each machine. There are emulators for some of the older machines. See http://simh.trailing-edge.com/ and http://simh.trailing-edge.com/links.html for some.
Here's an HP-2000 emulator:
1. Telnet to mickey.publicvm.com (yes, telnet)
2. Slowly alternate CTL-J and CTL-M until you see a “PLEASE LOG IN” message.
3. Enter “HEL-T001,HP2000,1″ . The resulting output includes:
Try exe-castle.b300, exe-kingdm.g100, exe-spawar.r500
To play the 1975 version of Oregon Trail type exe-oregon
To play the 1978 version of Oregon Trail type exe-ore2
To hunt the Wumpus, type exe-wumpus
Then "exe-oregon" DO YOU NEED INSTRUCTIONS (YES/NO)?YES
THIS PROGRAM SIMULATES A TRIP OVER THE OREGON TRAIL FROM
INDEPENDENCE, MISSOURI TO OREGON CITY, OREGON IN 1847.
YOUR FAMILY OF FIVE WILL COVER THE 2000 MILE OREGON TRAIL
IN 5-6 MONTHS --- IF YOU MAKE IT ALIVE.
YOU HAD SAVED $900 TO SPEND FOR THE TRIP, AND YOU'VE JUST
PAID $200 FOR A WAGON.Back in the 70s and early 80s it was like the 'hey day' of alternative hardware and software. There were dozens and dozens of systems, all with their own micro architecture, there are probably a bunch that are completely defunct, even if you had working hardware the software might be extinct. Wang, Kaypro, CDC, there were bunches of them...
The real warning shot this should be to everybody is for your personal media. The video and photos of your family. If you don't actively take part in archiving them (like regularly checking in on them, backing them up, copying them to new media, etc..) it is very possible, some would say likely that in 20, 30, maybe 50 years, you won't even be able to read the stuff. It's already a real chore to play a VHS tape.
http://www.computerhistory.org/groups/spg/ https://archive.org/details/software
My list which has many items still to be found: