From: Dennis Ritchie <dmr(a)plan9.bell-labs.com> Subject: [pups] Unix and PDP11/20 (was PDP9?) Date: Fri, 6 Sep 2002 02:08:02 -0400 Holden's link, http://www.psych.usyd.edu.au/pdp-11/11_20.html reinforces my guess that our first -11 probably did have just "PDP11" on the bezel. The one in my photo (which has the 20) is doubtless our second -11. I've looked at this page before, but it slipped my mind. Our first -11 was very early, and its disk took several months to arrive: it had TTY33 and high-speed paper tape as its only peripherals besides the clock. Early on, for fun, we tried assembling the DEC-supplied assembler, which came on at least one (maybe more) long fan-folded paper tapes. I don't think we ever succeeded; it had to be fed in twice for the two passes, and enough characters were dropped that phase errors occurred.