Radio Shack Color Computer (1982). I advertised in Color
Computer magazine to sell a "software spooler" I wrote and
sold for $14.95. I wrote it in assembler and it was basically
a ring buffer that stored printer output and used timer
interrupts to feed the very slow Radio Shack 600 baud dot
matrix impact printers of the time. "No more waiting for
your slow printer", I recall the ad read... I sold over 200
of them on cassette tape
First program written: 1968 on a GE timesharing service teletype.