PDP-15
 | |
 An incomplete PDP-15 | |
| Developer | Digital Equipment Corporation |
|---|---|
Product family | Programmed Data Processor |
| Type | Minicomputer |
| Released | February 1970 |
| Lifespan | 9 years |
Introductory price | 15,600 |
| Discontinued | 1979 |
| Units sold | 790 |
| DECsys, RSX-15, XVM/RSX, MUMPS, DOS-15 | |
| Platform | PDP 18-bit |
| Predecessor | PDP-9 |
The PDP-15 was an 18-bit minicomputer by Digital Equipment Corporation that first shipped in February 1970. It was the fifth and last of DEC's 18-bit machines, a series that had started in December 1959 with the PDP-1. More than 400 were ordered within the first eight months. A later model, the PDP-15/76, was bundled with a complete PDP-11, allowing the PDP-15 to use peripherals for the PDP-11's popular Unibus system. The last PDP-15 was produced in 1979, with total sales of about 790 units.
The PDP-15 was essentially a version of the earlier PDP-9 that was constructed using small-scale integration integrated circuits, which made it smaller and less expensive than the PDP-9's flip chips which used individual transistors. A basic 8 kW PDP-9 cost about $35,000 in 1968 (equivalent to $324,000 in 2025), whereas the PDP-15 with 4 kW was only $15,600 (equivalent to $129,000 in 2025) and a fully-equipped system with 8 kW, punch tape, KSR-35 terminal, math coprocessor and dual DECtape was $36,000 (equivalent to $298,000 in 2025), making a complete system significantly less expensive than the earlier machine.
In addition to operating systems, the PDP-15 has compilers for Fortran and ALGOL.