VAX-11

The VAX-11 was a family of minicomputers developed and manufactured by Digital Equipment Corporation (DEC) using processors implementing the VAX instruction set architecture (ISA). The VAX-11/780 was the first VAX computer.

VAX-11/780

The VAX-11/780, code-named "Star", was introduced on 25 October 1977 at DEC's Annual Meeting of Shareholders. It was the first computer to implement the VAX architecture. The VAX-11/780 central processing unit (CPU) was built from transistor-transistor logic (TTL) devices and had a 200 ns cycle time (5 MHz) and a 2 kB cache. Memory and I/O were accessed via the Synchronous Backplane Interconnect (SBI).

The VAX-11/780 supported 128 kB to 8 MB of memory (2 MB initially) through one or two memory controllers. Each memory controller supported 128 kB to 4 MB of memory. The memory was constructed from 4 or 16 kbit metal oxide semiconductor (MOS) RAM chips mounted on memory array cards. Each memory controller controlled up to 16 array cards. The memory was protected by error correcting code (ECC).