Hi folks, I'm interested in comparing notes with C programmers who have written programs for Unix v5, v6 and v7. Also I'm interested to know if there's anything similar to the scanf function for unix v5. Stdio and iolib I know well enough to do file IO but v5 predates iolib. Back in 1988 I tried to write a universal rubik's cube program which I called unirubik and after discovering TUHS I tried to backport it to v7 (which was easy) and v6 (which was a bit harder) and now I'm trying to backport it to v5. The v5 version currently doesn't have the any file IO capability as yet. Here are a few links to the various versions: http://www.maxhost.org/other/unirubik.c.v7 http://www.maxhost.org/other/unirubik.c.v6 http://www.maxhost.org/other/unirubik.c.v5 Also I've compiled the file utility from v6 in v5 and it seemed to work fine. Once I got /dev/mt0 working for unix v5 (thanks to Warren's help) I transferred the binary for the paging utility pg into it. This version of pg I believe was from 1BSD. I did some experimenting with math functions which can be seen here: http://www.maxhost.org/other/math1.c This will compile on unix v5. My initial impression of Unix v5 was that it was a primitive and almost unusable version of Unix but now that I understand it a bit better it seems a fairly complete system. I'm a bit foggy on what the memory limits are with v5 and v6. Unix v7 seems to run under simh emulating a PDP-11/70 with 2 megabytes of ram (any more than that and the kernel panics). Also I'd be interested in seeing the source code for Ken Thompson's APL interpreter for Unix v5. I know it does exist as it is referenced in the Unix v5 manual. The earliest version I could find was dated Oct 1976 and I've written some notes on it here: http://apl.maxhost.org/getting-apl-11-1976-to-work.txt Ok, that's about it for now. Is there any chance of going further back to v4, v3, v2 etc? Mark