I don't have any discussions I can point you at, but I do have source - for two things which are somewhat older than most of the ones you mention (ex/vi/etc). The first is a TECO from the fourth floor V6 machine (DSSR/RTS) at Tech Sq at MIT: http://ana-3.lcs.mit.edu/~jnc/tech/unix/teco There's some rudimentary documentation in there, in teco.doc, but don't expect too much. You'll have to rely on the source, which is in MACRO-11 - but it seems to be reasonably well commented. This actually predates V6; it was originally written for an MIT OS called DELPHI, which ran on an -11/45 which was the main EECS undergrad machine. At some point (probably post the Unix port), it was modified to have '^R mode', which was a WYSIWYG display mode a lot like the one in the ITS TECO in which EMACS was first written. I have also put up the Montgomery Emacs for Unix: http://ana-3.lcs.mit.edu/~jnc/tech/unix/emacs This is the version we were running on the 5th floor MIT V6 machine (CSR), which by that point have absorbed a few V7isms (e.g. some ioctl() stuff). So don't expect to be able to compile and run it, without a fair amount of work. (I vaguely recall that it needs I+D space, so maybe not on a /23 at all.) But at least the source is in C, so you can read it. I don't think there's an un-modified version online (i.e. the original Montgomery source), alas. Noel