VAX

VAX 11-780 intero

VAX VMS logo

DEC-VAX-8350-front-0a

Microvax 3600 (2)

SPEC-1 VAX 05

VAX is a series of computers developed by Digital Equipment Corporation (DEC), first released in 1977. The name VAX stands for "Virtual Address eXtension," reflecting the system's enhanced memory management capabilities over its predecessors. VAX systems were designed to support a wide range of operating systems, with VMS (Virtual Memory System) being the most prominently associated. These computers played a significant role in the development of networking, distributed computing, and the growth of the Internet.

History

The VAX series was introduced as a successor to DEC's PDP-11, aiming to provide a more powerful and flexible computing environment. The first model, the VAX-11/780, was considered revolutionary for its time, offering capabilities such as virtual memory and high-level language support, which facilitated more efficient software development. Over the years, DEC expanded the VAX line to include models of varying sizes and performance levels, from desktop workstations to large-scale servers.

Architecture

VAX computers are known for their CISC (Complex Instruction Set Computing) architecture, which includes a rich set of instructions designed to perform complex operations in a single step. This architecture was aimed at optimizing the performance of high-level languages like FORTRAN and COBOL, making VAX systems particularly suitable for scientific and business applications. The VAX architecture also featured support for virtual memory, allowing programs to use more memory than physically available on the machine by swapping data to and from disk.

Operating Systems

While VAX machines could run several operating systems, VMS was the primary OS developed by DEC specifically for the VAX architecture. VMS featured advanced capabilities such as clustering, file versioning, and comprehensive security features, which made it popular for critical applications in finance, manufacturing, and government sectors. Other operating systems available for VAX computers included several versions of UNIX, BSD, and ULTRIX.

Decline and Legacy

The popularity of VAX systems began to wane in the 1990s, as the industry shifted towards RISC (Reduced Instruction Set Computing) architectures and the emergence of more powerful and cost-effective microprocessors from competitors like Intel and Sun Microsystems. DEC eventually transitioned its focus to the Alpha line of processors, which were based on RISC principles. Despite the decline, VAX computers left a lasting impact on the computing world, particularly in the areas of networking and distributed computing. The design principles and technologies developed for VAX systems influenced subsequent generations of computers and operating systems.

See Also

• PDP-11
• Digital Equipment Corporation
• Virtual Memory System (VMS)
• Complex Instruction Set Computing (CISC)
• Reduced Instruction Set Computing (RISC)