PDP-11/03

The PDP-11/03, introduced in July 1976, is a compact yet powerful mini-computer built around four Large Scale Integration (LSI) chips mounted on a single 8.5-by-10.5-inch printed circuit board, all contained within a rack-mountable assembly.

It boasts an extensive instruction set of over 400 commands, emulating the PDP-11/34, and is fully compatible with existing PDP-11/35 and /40 software, including assemblers, editors, and higher-level languages. Standard architectural features include hardware stack processing, eight general-purpose registers, vectored interrupts, and single/double operand addressing.

The system offers a powerful I/O structure with priority-structured I/O and Direct Memory Access (DMA). Its modular design allows for flexible expansion of memory (beyond the on-board 4KB MOS RAM, offering nonvolatile, dynamic RAM, and PROM/ROM options) and peripherals. Additional features include a power-fail/auto-restart capability for reliability and a wide range of addressing modes for efficient program storage. A comprehensive software suite, including the RT-11 real-time disk operating system, multi-user BASIC, single-user BASIC, and FORTRAN, is available.