OpenVMS

OpenVMS, often called VMS, is a special kind of operating system that can handle many users and tasks at the same time. It was made to support different types of work, like sharing time among users, processing jobs in batches, handling many transactions quickly, and running workstation applications. Many important places like banks, hospitals, and telecommunications companies use OpenVMS to keep their systems running smoothly.

OpenVMS was first introduced by Digital Equipment Corporation in 1977 along with the VAX-11/780 minicomputer. Over the years, it has been updated to work on different types of computers, including DEC Alpha systems, Itanium-based HPE Integrity Servers, and some x86-64 hardware and hypervisors. Since 2014, a company called VMS Software Inc. has been taking care of developing and supporting OpenVMS.

One of the biggest advantages of OpenVMS is its ability to keep systems running without stopping, even when doing maintenance or if part of the system stops working. This is done through clustering, where the system is spread over several machines. This way, important applications and data stay available all the time, and there are stories of these clusters running for up to 17 years without stopping.

History

In April 1975, Digital Equipment Corporation (DEC) started a project to create a new kind of computer system and operating system. The hardware was called Star, and the operating system was named Starlet. The goal was to make an operating system that could handle many users at once, run jobs in the background, and manage tasks smoothly.

Over time, this system evolved. By the early 1980s, it became very popular, especially in businesses. DEC later renamed the system to OpenVMS in 1992 to show its support for modern technology standards. OpenVMS was later adapted to run on different types of computer chips, including those made by Intel and others, so it could keep working as technology changed.

Architecture

The OpenVMS operating system is built in layers for safety and organization. The most important layer is called the Executive, which handles key tasks and has special access rights. Below this, there are tools and libraries that regular programs use.

OpenVMS uses special features of the computer’s hardware to manage tasks, memory, and interruptions. These features help keep everything running smoothly and safely, no matter what kind of work the system is doing.

Features

OpenVMS supports clustering, where multiple computers run the operating system and share devices like disk drives and printers. These clustered computers can operate independently or work together, providing a single system image. This setup allows up to 96 computers to work as one, supporting applications even during upgrades or unexpected outages.

The system integrates well with networks, allowing remote logins and access to files and printers over networks. It supports various protocols, including DECnet and TCP/IP, and can connect to personal computers and other devices. OpenVMS also offers many programming languages and development tools, making it versatile for different software needs. Users can interact with the system using text-based or graphical interfaces, depending on their preferences and hardware.

Hobbyist programs

In 1997, OpenVMS became free for hobbyists to use, allowing people to enjoy it without cost. Before computers could run OpenVMS directly, many used special programs called emulators to mimic older machines.

In 2020, the company HPE stopped their free program, but another company, VSI, started a new one called the Community License Program. This new program lets people use OpenVMS on certain types of computers, though it does not include versions for older VAX systems.

Release history

OpenVMS, also called VMS, is an operating system that allows many people to use a computer at the same time. It can handle different types of work, like letting people share time on the computer, processing jobs in batches, handling many transactions quickly, and supporting workstation applications. Many important places use OpenVMS, such as banks, hospitals, telecommunications companies, and factories.