1979 · Microprocessor Study Kit · Work 912 of 1,871
A kitchen table in a terraced house in England on a winter evening, on a red and white checked tablecloth a bare green circuit board twenty centimetres long, a long black chip in its middle, smaller black chips, a silver crystal can, blue capacitors, small dark red display windows glowing faintly along the top, at the upper right two tiny traffic lights of red, yellow and green diodes with the red and green lit, a block of fifteen plain pale grey keys, a closed course booklet lying back cover up, a cup of tea, a hand in a knitted jumper sleeve pressing one grey key, warm lamp light.
What it was used for
The PT501 was a teaching device of the British Open University. The Science Museum records an "Open University PT501microprocessor study kit, with associated course notes", with a board of 21 x 140 x 205 mm, a power supply and a box of 120 x 365 x 235 mm, made between 1977 and 1983. According to the Old Computer Museum the board carried an Intel 8049 with 128 bytes of RAM and 2048 bytes of ROM; it "was designed for study or general principles of microprocessors" and was issued for a course called "Microprocessors and Product Development". It came with a booklet of 39 experiments, and the board held a temperature display and 2 sets of traffic lights that the processor switched.
What was new
The characteristic thing was the direction of the teaching: the experiment booklet led from an introduction to programming to 39 experiments, and on the traffic lights and the temperature display the student watched the processor at work. The barb lies in the form of the university. A distance university cannot set up its laboratory, it has to post it: what elsewhere stood in a teaching lab arrived here with a power supply and course notes in a box of 120 x 365 x 235 mm - and was limited to whatever fitted into that box.
What the sources leave open: The processor, memory sizes, course name and the 39 experiments rest on the Old Computer Museum alone, a collector site; it dates the PT501 to 1979. The Science Museum, by contrast, gives a range of 1977 to 1983 and names no processor. No source gives student numbers, units made or price. A Centre for Computing History page could not be retrieved in this run.