From mboxrd@z Thu Jan 1 00:00:00 1970 From: cdl@mpl.ucsd.edu (Carl Lowenstein) Date: Fri, 6 Sep 2002 17:36:52 -0700 (PDT) Subject: [pups] Unix and PDP11/20 (was PDP9?) Message-ID: <200209070036.RAA10988@opihi.ucsd.edu> > From: Dennis Ritchie > 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. I was there once myself. The problem was fuzzy holes in the DEC-punched fan-fold paper tape. So I toggled in a small utility program "wait, read, wait, punch, loop" to copy from the TTY reader to the high-speed punch. The sensing pins of the TTY had no trouble with the fuzzy holes, and I got paper tapes that worked in the high-speed reader. carl -- carl lowenstein marine physical lab u.c. san diego clowenst at ucsd.edu