Complex sentence: VAX was a 32-bit complex instruction set computer (CISC) instruction set architecture (ISA) developed by Digital Equipment Corporation (DEC) in the mid- 1970s, designed to extend or replace the various Programmed Data Processor (PDP) ISAs.
Split into simpler sentences: VAX was a computer processor instruction set architecture (ISA) developed by Digital Equipment Corporation (DEC) in the mid- 1970s. A 32-bit complex instruction set computer (CISC) ISA, it was designed to extend or replace DEC's various Programmed Data Processor (PDP) ISAs.