Ancient Computing Machinery

«Those who scorn computer history are those who really don't grasp what is happening today and will never really shape tomorrow.»
-Don Congdon
The criterion for the Ancient Computing Machinery Project embodied three major points:
  1. that the simulation be a reasonable facsimile of the original;
  2. that it embody the complete functionality of the original;
  3. that it have a teaching-mode built-in.
This project stopped dead in its tracks (just after my xabacus was completed) when I read (a cover story in a Scientific American) that the Science Museum in London, U.K. had built a working copy of Babbage's difference engine. John Walker has Java simulation of Babbage's Engine that you can program on-line.

Here are some ancient computers

+Snapshot+ (48K) IBM Selective Sequence Electronic Calculator from 1948. This system had three levels of memory: electronic, relay, paper tape.
(Left side) The first cabinet contains card reading tubes. The second contains sequence tubes. The next four contain sequence relays. The first gentleman is standing in front of the table look-up.
The three large circular objects in the back are spools of 80 column paper tape. Each spool is feed into a punch unit and into three separate tape readers.
(Right side) Arithmetical unit, pulse generator, sequence interlocks, electronic memory.
+Snapshot+ (30K) DEC PDP1
+Snapshot+ (17K) DEC PDP1 front-panel closeup.
+Snapshot+ (31K) DEC PDP6
+Snapshot+ (30K) LGP-30, manufactured by Librascope in about 1960. It has been described as the minicomputer of the vacuum tube era. The machine is imortalized in the story of Mel, a "real" computer programmer, as retold in _The New Hackers Dictionary_.
+Snapshot+ (18K) PDP1 display with a spacewar game in progress.
Images scanned by Clarke Thacher
Last modified: Sun Nov 23 18:50:10 2003