The first publicized (ie,
in print)
BBS was
Bullet-80 written for the
TRS-80 series of computers made by
Tandy/
Radio Shack in the early
80's.
Bullet-80 was designed to run to a TRS-80 Model III with 64K of RAM and upto four 180K 5 1/4" floppies. It contained a message forum with threads and searching, a download area with upto 500 files and a built-in display interrupt driver that linked all output to the screen to the serial port.