See also: VAX | DEC | Microkernel

Aka: Virtual Memory System


The original multi-user OS for the 32-bit CISC VAX. Many years later after the VAX era, OpenVMS got ported to the 64-bit RISC Alpha, by DEC in the beginning of the 90s. OpenVMS 8.2 for Alpha and HP Integrity (Itanium) was announced in january 2005 ( This is the first production-quality release of the Itanium port.

OpenVMS had various innovative or otherwise unique features. It was (and some would argue still is), together with VAXen, excellent for clustering environments. For example, the shell/CLI integrates tightly into such clusters; one can ‘log in’ to another node by simply changing a variable. Another interesting aspect was the filesystem, which had advanced ACLs and versioning; the former is still a problem in modern Unices, the latter is not possible as filesystem layer on UNIX since its not implemented in any UNIX filesystem. Userspace applications such as CVS may be a viable solution though. Finally, the OS was a production-quality microkernel, also fairly uncommon.

OpenVMS was programmed in a wide number of programming languages. A hobbyist license for non-commercial use only, lasting one year, is free.


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