Yes; some of the history is given here: An incomplete history of the QED Text Editor https://www.bell-labs.com/usr/dmr/www/qed.html Ken would have run into the original on the Berkeley Time-Sharing System; he apparently wrote the CTSS one based on his experience with the one on the BTSS. Oddly enough, CTSS seems to have not had much of an editor before. The Programmer's Guide has an entry for 'Edit' (Section AH.3.01), but 'edit file' seems to basically do a (in later terminology) 'cat >> file'. Section AE seems to indicate that most 'editing' was done by punching new cards on a key-punch! The PDP-1 was apparently similar, except that it used paper tape. Editing paper tapes was difficult enough that Dan Murphy came up with TECO - original name 'Tape Editor and Corrector': https://opost.com/tenex/anhc-31-4-anec.pdf I learned it from reading the 'sh' and 'ed' V6 man pages. The MIT V6 systems had TECO (with a ^R mode even), but I started out with ed, since it was more like editors I had previously used. Noel