Exploring ITS

ITS, the Incompatible Timesharing System, was an operating system for the Digital Equipment Corporation PDP-6 and PDP-10 computers developed at MIT Artificial Intelligence Laboratory in the 1960s and 1970s.

Today, SDF runs a publicly accessible ITS system on a PDP-10 emulator.

Connecting to the SDF ITS System

tvcon -2BCS hactrn.org -p 11100

You’d normally log in by pressing C-z, but in TVCON, we need to press F1 instead.

Log in with :LOGIN <user>, or :LOGIN <user>$U (where $ is an ESCAPE)

Don’t forget to :LOGOUT when you’re done!

Basic Commands

UNIX CommandDDT CommandMonitor CommandNote
ls <dir><dir>^F:listf <dir>
ls /^R m.f.d. (file)print m.f.d. (file)[1]
mkdir <dir>^R <dir>;..new. (udir):print <dir>;..new. (udir)


  1. "m.f.d. (file)" is the literla name of the Master File Directory on the disk.


..CLOBRFIf nonzero, FOO^K (start a new FOO) clobbers an existing FOO
..MORWARNIf nonzero, --More-- will always display (Space=yes, Rubout=no)