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 have submodels, the PDP-7A