Open Virtual Memory System (OpenVMS)

Definition - What does Open Virtual Memory System (OpenVMS) mean?

Open Virtual Memory System (OpenVMS) is a 32-bit operating system developed by Digital Equipment Corporation (DEC) in 1979 as a computer server OS that runs on their VAX family of computers, which succeeded the PDP-11 line.

It has a complete graphical user interface with graphics support and made heavy use of the concept of virtual memory in order to promote multi-user, time sharing, and batch processing capabilities.

Techopedia explains Open Virtual Memory System (OpenVMS)

OpenVMS was originally just called Virtual Memory System (VMS), but it was changed to OpenVMS when it was retooled to work for the Alpha processor family. The "Open" does not denote open source but rather it suggests the new added support for UNIX-like interfaces from the Portable Operating System Interface (POSIX) standard which includes standard C functions that can be ported to any POSIX-supporting system.

OpenVMS supports multi-user, time-sharing, batch, real-time and transaction processing through the use of virtual memory and offers high availability through clustering by distributing the system over many physical machines. Clustering allows the system to be somewhat disaster tolerant as it can still function even when individual data processing facilities become unavailable.

OpenVMS also pioneered many features that are now standard on high-end server operating systems like:

Integrated networking
Integrated database features as record management services (RMS)
Layered databases like relational databases
Distributed file system
Symmetrical, asymmetrical, and non-uniform memory access (NUMA) multiprocessing
Clustering
Shell command language
High level of security
Hardware partitioning for multiprocessors
Multiple programming language support with standardized interoperability mechanism calls between those languages