VAX
| Designer | Digital Equipment Corporation |
|---|---|
| Bits | 32-bit |
| Introduced | 1977 |
| Design | CISC |
| Type |
|
| Encoding | Variable (1 to 56 bytes) |
| Branching | Condition code |
| Endianness | Little |
| Page size | 512 bytes |
| Extensions | PDP-11 compatibility mode, VAX Vector Extensions, VAX Virtualization Extensions |
| Open | No |
| Predecessor | PDP-11 |
| Successor | Alpha |
| Registers | |
| General-purpose | 16 × 32-bit |
| Floating-point | not present, uses the GPR |
| Vector | 16 × 4096-bit (64 elements of 64 bits each) |
VAX (an acronym for virtual address extension) is a series of computers featuring a 32-bit instruction set architecture (ISA) and virtual memory that was developed and sold by Digital Equipment Corporation (DEC) in the late 20th century. The VAX-11/780, introduced October 25, 1977, was the first of a range of popular and influential computers implementing the VAX ISA. The VAX family was a huge success for DEC, with the last members arriving in the early 1990s. The VAX was succeeded by the DEC Alpha, which included several features from VAX machines to make porting from the VAX easier.