VAXVMS

VAX/VMS, commonly referred to as VMS, is the operating system originally developed by Digital Equipment Corporation for its VAX family of minicomputers. It was introduced in 1977 as a virtual-memory, multi-user, multitasking system designed to support large, mission-critical workloads with high reliability and security. The product line later evolved and was rebranded OpenVMS as the platform expanded to newer hardware generations.

Its feature set includes a fully virtualized memory system, integrated security model, and robust I/O subsystems. The OS provides a built-in user interface via the Digital Command Language (DCL), a wide range of system services, and support for multi-process scheduling, interprocess communication, and clustering through VAXcluster. File management centers on the Files-11 file system with RMS (Record Management Services) for structured data files. Networking support includes DECnet and, later, TCP/IP stacks.

OpenVMS emphasized reliability, availability, and serviceability, with features such as journaling and fault containment, extensive logging, and hot-swappable components in certain hardware configurations. Its architectural design integrated subsystems for process management, I/O, and system management, making it suitable for enterprise environments including finance, government, and manufacturing.

With the decline of VAX hardware, DEC ported the OS to the Alpha architecture in the 1990s and renamed the product OpenVMS. The OpenVMS line has continued under later owners, notably VSI (VMS Software Inc.), which maintains ongoing development and modern ports on newer platforms while preserving compatibility with historical VMS applications and tooling.