PDP-9

The PDP-9, the 4th of the five 18-bit minicomputers produced by Digital Equipment Corporation, was introduced in 1966. A total of 445 PDP-9 systems were produced, of which 40 were the compact, low-cost PDP-9/L units.
History.
The 18-bit PDP systems preceding the PDP-9 were the PDP-1, PDP-4 and PDP-7. Its successor was the PDP-15.
Hardware.
The PDP-9, which was "two metres wide and about 75cm deep," was approximately twice the speed of the PDP-7. It was built using discrete transistors, and had an optional integrated vector graphics terminal. The PDP-9 weighed about and the PDP-9/L weighed about .
It was DEC's first microprogrammed machine.
A typical configuration included:
Among the improvements of the PDP-9 over its PDP-7 predecessor were:
User/university-based research projects for extending the PDP-9 included:
Software.
The system came with a single-user Keyboard monitor. DECsys, provided an interactive, single user, program development environment for Fortran and assembly language programs.
Both FORTRAN II and FORTRAN IV were implemented for the PDP-9.
MUMPS was originally developed on the PDP-7, and ran on several PDP-9s at the Massachusetts General Hospital.
Sales.
The PDP-7, of which 120 were sold, was described as "highly successful.". The PDP-9 sold 445 units. Both had submodels, the PDP-7A and the PDP-9/L, neither of which accounted for a substantial percentage of sales.