An 32-bit complex instruction set computer (CISC) instruction set architecture by Digital Equipment Corporation. Many DEC CPUs were compatible.
The first video game about DEC VAX was released in 1991.
This is marked as hardware due to it's having no real-world use outside of a CPU. As a technical matter, it is closer to software but is an instruction set standard (neither hardware nor software?). Many DEC CPUs used VAX and the computers with these CPUs used 'VAX' based names.