Wednesday, April 20, 2011

PDP-11 Emulator running V6 Unix - in Javascript!


I was in high school when I got my first Unix account on a computer science system at the university. It might have been a PDP-11. I remember struggling to teach myself C from Kernighan and Ritchie when all I knew was Basic. And of course way too shy to actually ask anyone for help.


Larry Reid said...

Some people have too much time on their hands.

Yes, the computer you used back then was a PDP-11/40 with 128 KB of RAM (64 KB code and 64 KB data), an rk05 disk pack for Unix (around 2.2 MB if I recall correctly) and another disk (not DEC, I don't remember the name) for all user files. The user disk was 6 MB, and we had another one of them to back up the user files. We were running Unix v6. After learning C without documentation, I remember what a revelation it was to read K&R and go, "Oh, that's why it does what it does."

Most of the grad students in Computational Science and a number of us geekier undergrads used that box. At busy times, "who" would show 10-15 people typing documents to be formatted by nroff or troff, or running adb to debug their C programs.

The scary part for me: I got into the emulator and started Unix. I did "ls", then tried to cd into a directory. "cd" didn't work. Somewhere from way back in my memory popped out the thought, "cd was just a shell define. The command was chdir". Sure enough. chdir works. How the hell did I remember that?

Anonymous said...

Most Excellent! I remember my dad sitting me down at the terminal of the trouble reporting system in one of Ma Bell's COs in the late 70's or real early 80's and trying to explain shells and privileges to my brother and I. We are both engineers now--him a real one with an engineering degree and all. I'm pretty sure the trouble reporting system was either a PDP11 or a VAX running system 6 or 7.