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OpenVMS previously known as VAX-11/VMS, VAX/VMS or (informally) VMS, is a computer server operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

 that runs on VAX
VAX
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...

, Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...

 and Itanium
Itanium
Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...

-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase. Unlike some other mainframe-oriented operating systems, OpenVMS has a graphical user interface
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

 (GUI) with complete graphics support. Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

's VAX was one of the three top-selling workstations lines in the 1980s and 1990s. VMS had support for professional DTP and CAE software . Software for AXP based systems was promoted by Digital's ASAP program (Association of Software and Application Partners) and could be found in the extensive "Alpha Applications Catalog". AXP VMS
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...

 supported OpenGL
OpenGL
OpenGL is a standard specification defining a cross-language, cross-platform API for writing applications that produce 2D and 3D computer graphics. The interface consists of over 250 different function calls which can be used to draw complex three-dimensional scenes from simple primitives. OpenGL...

 and Accelerated Graphics Port
Accelerated Graphics Port
The Accelerated Graphics Port is a high-speed point-to-point channel for attaching a video card to a computer's motherboard, primarily to assist in the acceleration of 3D computer graphics. Since 2004 AGP has been progressively phased out in favor of PCI Express...

 (AGP) graphics adapters.

OpenVMS is a multi-user
Multi-user
Multi-user is a term that defines an operating system or application software that allows concurrent access by multiple users of a computer. Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered "multi-user", to avoid leaving the...

, multiprocessing
Multiprocessing
Multiprocessing is the use of two or more central processing units within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them...

 virtual memory
Virtual memory
In computing, virtual memory is a memory management technique developed for multitasking kernels. This technique virtualizes a computer architecture's various forms of computer data storage , allowing a program to be designed as though there is only one kind of memory, "virtual" memory, which...

-based operating system (OS)
designed for use in
time sharing,
batch processing
Batch processing
Batch processing is execution of a series of programs on a computer without manual intervention.Batch jobs are set up so they can be run to completion without manual intervention, so all input data is preselected through scripts or command-line parameters...

,
real-time
Real-time operating system
A real-time operating system is an operating system intended to serve real-time application requests.A key characteristic of a RTOS is the level of its consistency concerning the amount of time it takes to accept and complete an application's task; the variability is jitter...


(where process priorities can be set higher than OS kernel jobs),
and transaction processing
Transaction processing
In computer science, transaction processing is information processing that is divided into individual, indivisible operations, called transactions. Each transaction must succeed or fail as a complete unit; it cannot remain in an intermediate state...

.
It offers high system availability
Availability
In telecommunications and reliability theory, the term availability has the following meanings:* The degree to which a system, subsystem, or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, i.e., a random, time...

 through clustering, or the ability to distribute the system over multiple physical machines. This allows the system to be "disaster-tolerant" against disasters that may disable individual data-processing facilities. VMS also includes a process priority system that allows for real-time processes to run unhindered, while user processes get temporary priority "boosts" if necessary.

OpenVMS commercialized many features that are now considered standard requirements for any high-end server operating system. These include:
  • Integrated computer networking (originally DECnet
    DECnet
    DECnet is a suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus transforming DEC into a networking powerhouse in the 1980s...

     and later, TCP/IP)
  • Symmetrical, asymmetrical, and NUMA
    Non-Uniform Memory Access
    Non-Uniform Memory Access is a computer memory design used in Multiprocessing, where the memory access time depends on the memory location relative to a processor...

     multiprocessing, including clustering
  • A distributed file system
    File system
    A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...

     (Files-11
    Files-11
    Files-11, also known as on-disk structure, is the file system used by Hewlett-Packard's OpenVMS operating system, and also by the older RSX-11...

    )
  • Integrated database
    Database
    A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

     features such as RMS
    Record Management Services
    Record Management Services are procedures in the VMS, RSTS/E, RT-11 and high-end RSX-11 operating systems that programs may call to process files and records within files. VMS RMS is an integral part of the system software; its procedures run in executive mode...

     and layered databases including Rdb
    Oracle Rdb
    Rdb/VMS is a relational database management system for the Hewlett-Packard OpenVMS operating system. It was originally created by Digital Equipment Corporation in 1984 as part of the VMS Information Architecture, intended to be used for data storage and retrieval by high-level languages and/or...

  • Support for multiple computer programming language
    Programming language
    A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

    s
  • A standardized interoperability mechanism for calls between different programming languages
  • An extensible shell
    Shell (computing)
    A shell is a piece of software that provides an interface for users of an operating system which provides access to the services of a kernel. However, the term is also applied very loosely to applications and may include any software that is "built around" a particular component, such as web...

     command language (DIGITAL Command Language
    DIGITAL Command Language
    DCL, the DIGITAL Command Language, is the standard command languageadopted by most of the operating systems that were sold by the former Digital Equipment Corporation...

    )
  • Hardware partitioning of multiprocessors
  • High level of security


Enterprise-class environments typically select and use OpenVMS for various purposes including as a mail server, network services, manufacturing or transportation control and monitoring, critical applications and databases, and particularly environments where system uptime and data access is critical. System up-times of a decade or more have been reported, and features such as Rolling Upgrades and clustering allow clustered applications and data to remain continuously accessible while operating system software and hardware maintenance and upgrades are performed, or when a whole data center is destroyed. Customers using OpenVMS include banks and financial services, hospitals and healthcare, network information services, and large-scale industrial manufacturers of various products.

Origin and name changes



In April 1975, Digital Equipment Corporation
Digital Equipment Corporation
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...

 embarked on a hardware project, code named Star, to design a 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....

 virtual address extension to its PDP-11
PDP-11
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...

 computer line. A companion software project, code named Starlet, was started in June 1975 to develop a totally new operating system, based on RSX-11M
RSX-11
RSX-11 is a family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation , common in the late 1970s and early 1980s. RSX-11D first appeared on the PDP-11/40 in 1972...

, for the Star family of processors. These two projects were tightly integrated from the beginning. Gordon Bell
Gordon Bell
C. Gordon Bell is an American computer engineer and manager. An early employee of Digital Equipment Corporation 1960–1966, Bell designed several of their PDP machines and later became Vice President of Engineering 1972-1983, overseeing the development of the VAX...

 was the VP lead on the VAX hardware and its architecture. Roger Gourd was the project lead for the Starlet program, with software engineers Dave Cutler
Dave Cutler
David Neil Cutler, Sr. is an American software engineer, designer and developer of several operating systems including RSX-11M, VMS and VAXELN at Digital Equipment Corporation and Windows at Microsoft.- Personal history :...

 (who would later lead development of Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...

's Windows NT
Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...

), Dick Hustvedt
Dick Hustvedt
Richard Irvin Hustvedt was a renowned software engineer, designer and developer of several operating systems including the RSX-11, and VMS systems of Digital Equipment Corporation...

, and Peter Lippman acting as the technical project leaders, each having responsibility for a different area of the operating system. The Star and Starlet projects culminated in the VAX
VAX
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...

 11/780 computer and the VAX-11/VMS operating system. The Starlet name survived in VMS as a name of several of the main system libraries, including STARLET.OLB and STARLET.MLB.

Over the years the name of the product has changed. In 1980 it was renamed, with version 2.0 release, to VAX/VMS (at the same time as the VAX-11 computer was renamed to simply VAX). With the introduction of the MicroVAX
MicroVAX
The MicroVAX was a family of low-end minicomputers developed and manufactured by Digital Equipment Corporation . The first model, the MicroVAX I, was introduced in 1984...

 range such as the MicroVAX I, MicroVAX II and MicroVAX 2000 in the mid-to-late 1980s, DIGITAL released MicroVMS versions specifically targeted for these platforms which had much more limited memory and disk capacity; e.g. the smallest MicroVAX 2000 had a 40MB RD32 hard disk and a maximum of 6MB of RAM, and its CPU had to emulate some of the VAX floating point instructions in software. MicroVMS kits were released for VAX/VMS 4.4 to 4.7 on TK50
Digital Linear Tape
Digital Linear Tape is a magnetic tape data storage technology developed by Digital Equipment Corporation from 1984 onwards. In 1994 the technology was purchased by Quantum Corporation, who currently manufactures drives and licenses the technology and trademark. A variant with higher capacity...

 tapes and RX50 floppy disks, but discontinued with VAX/VMS 5.0. In 1991 it was renamed again to OpenVMS to indicate its support for industry standards such as POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...

 and Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 compatibility, and to drop the hardware connection as the port to DIGITAL's 64-bit
64-bit
64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...

 Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...

 RISC processor was in process. The OpenVMS name first appeared after the version 5.4-2 release.

Port to DEC Alpha


The VMS port to Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...

 resulted in the creation of a second and separate source code libraries (based on a source code management tool known as VDE) for the VAX
VAX
VAX was an instruction set architecture developed by Digital Equipment Corporation in the mid-1970s. A 32-bit complex instruction set computer ISA, it was designed to extend or replace DEC's various Programmed Data Processor ISAs...

 32-bit
32-bit
The range of integer values that can be stored in 32 bits is 0 through 4,294,967,295. Hence, a processor with 32-bit memory addresses can directly access 4 GB of byte-addressable memory....

 source code library and a second and new source code library for the Alpha (and the subsequent Itanium
Itanium
Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...

 port) 64-bit
64-bit
64-bit is a word size that defines certain classes of computer architecture, buses, memory and CPUs, and by extension the software that runs on them. 64-bit CPUs have existed in supercomputers since the 1970s and in RISC-based workstations and servers since the early 1990s...

 architectures. 1992 saw the release of the first version of OpenVMS for Alpha AXP systems, designated OpenVMS AXP V1.0. The decision to use the 1.x version numbering stream for the pre-production quality releases of OpenVMS AXP caused confusion for some customers and was not repeated in the next platform port to the Itanium.

In 1994, with the release of OpenVMS version 6.1, feature (and version number) parity between the VAX and Alpha variants was achieved. This was the so-called Functional Equivalence release, in the marketing materials of the time. Some features were missing however, e.g. based shareable images, which were implemented in later versions. Subsequent version numberings for the VAX and Alpha variants of the product have remained consistent through V7.3, though Alpha subsequently diverged with the availability of the V8.2 and V8.3 releases.

For general details on the port to Alpha, see the OpenVMS 20th Anniversary book. For technical details on the port, see the DIGITAL Technical Journal Volume 4 Number 4.

Port to Intel Itanium


In 2001, just prior to its acquisition by Hewlett-Packard
Hewlett-Packard
Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

, Compaq
Compaq
Compaq Computer Corporation is a personal computer company founded in 1982. Once the largest supplier of personal computing systems in the world, Compaq existed as an independent corporation until 2002, when it was acquired for US$25 billion by Hewlett-Packard....

 announced the port of OpenVMS to the Intel Itanium
Itanium
Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...

 architecture. This port was accomplished using source code maintained in common within the OpenVMS Alpha source code library, with conditional and additional modules where changes specific to Itanium were required. The OpenVMS Alpha pool was chosen as the basis of the port as it was significantly more portable than the original OpenVMS VAX source code, and because the Alpha source code pool was already fully 64-bit capable (unlike the VAX source code pool). With the Alpha port, many of the VAX hardware-specific dependencies had been previously moved into the Alpha SRM firmware for OpenVMS. Features necessary for OpenVMS were then moved from SRM into OpenVMS I64 as part of the Itanium port.

Unlike the port from VAX to Alpha, in which a snapshot of the VAX code base circa V5.4-2 was used as the basis for the Alpha release and the 64-bit source code pool then diverged, the OpenVMS Alpha and I64 (Itanium) versions of OpenVMS are built and maintained using a common source code library and common tools. The core software source code control system used for OpenVMS is the VMS Development Environment (VDE); see the VDE installation kit for details.

Two pre-production releases, OpenVMS I64 V8.0 and V8.1, were available on June 30, 2003 and on December 18, 2003. These releases were intended for HP organizations and third-party vendors involved with porting software packages to OpenVMS I64.

The following are recent OpenVMS I64 releases:

OpenVMS I64 V8.2, the first production-quality Itanium release, was shipped January 13, 2005. A V8.2 release is also available for Alpha platforms.

OpenVMS I64 V8.2-1, adding support for Integrity Superdome and cell based systems, was released in September 2005. V8.2-1 is available for Itanium platforms only.

OpenVMS I64 V8.3, was released for Itanium platforms in September 2006. V8.3 is also available for Alpha systems.

OpenVMS I64 V8.3-1H1, was released in October 2007. It features full c-Class Integrity BladeServer blade support. See the full announcement for details.HP BladeSystem information for details on blade server
Blade server
A blade server is a stripped down server computer with a modular design optimized to minimize the use of physical space and energy. Whereas a standard rack-mount server can function with a power cord and network cable, blade servers have many components removed to save space, minimize power...

 products from HP.

OpenVMS I64 and Alpha V8.4, was released in June 2010. See the OpenVMS V8.4 release announcement for details.

For technical details on the OpenVMS port to Itanium, see the OpenVMS Technical Journal V6. In particular, see the Porting OpenVMS to Integrity article. Information on OpenVMS releases from V4.0 to current is available, as are listings of upgrade paths in the OpenVMS FAQ and at the HP OpenVMS site.

Major release timeline

Date Version Note
October 25, 1977 V1.0 Initial commercial release
April, 1980 V2.0 VAX-11/750
VAX-11
The VAX-11 was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture . The VAX-11/780 was the first VAX computer.- VAX-11/780 :...

April, 1982 V3.0 VAX-11/730
VAX-11
The VAX-11 was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture . The VAX-11/780 was the first VAX computer.- VAX-11/780 :...

September, 1984 V4.0 VAX 8600
VAX 8000
The VAX 8000 was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture .- VAX 8600 :...

 and MicroVMS (for MicroVAX
MicroVAX
The MicroVAX was a family of low-end minicomputers developed and manufactured by Digital Equipment Corporation . The first model, the MicroVAX I, was introduced in 1984...

)
April, 1988 V5.0 VAX 6000
VAX 6000
The VAX 6000 was a family of minicomputers developed and manufactured by Digital Equipment Corporation using processors implementing the VAX instruction set architecture...

November, 1992 V1.5 first OpenVMS AXP (Alpha) specific version
June, 1993 V6.0 VAX 7000 and 10000
VAX 7000/10000
The VAX 7000 and VAX 10000 were a series of high-end multiprocessor minicomputers developed and manufactured by Digital Equipment Corporation , introduced in July 1992. These systems used microprocessors implementing the VAX instruction set architecture...

April/May, 1994 V6.1 merging of VAX and Alpha AXP version numbers
January, 1996 V7.0 full 64-bit virtual addressing on Alpha
1997 V7.1
June, 2003 V8.0 limited availability eval for Integrity
February, 2005 V8.2 Common Alpha and Itanium release
September, 2006 V8.3 Alpha, Itanium dual-core support
October, 2007 V8.3-1H1 c-Class Integrity blade server support
June, 2010 V8.4 Added support for running as a virtual machine guest under HPVM

Graphical user interface


OpenVMS uses the DECwindows Motif
Motif (widget toolkit)
In computing, Motif refers to both a graphical user interface specification and the widget toolkit for building applications that follow that specification under the X Window System on Unix and other POSIX-compliant systems. It emerged in the 1980s as Unix workstations were on the rise, as a...

 user interface (based on CDE
Common Desktop Environment
The Common Desktop Environment is a desktop environment for Unix and OpenVMS, based on the Motif widget toolkit.- Corporate history :...

) layered on top of OpenVMS's X11
X Window System
The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...

 compliant windowing system.

Clustering


OpenVMS supports clustering (first called VAXcluster and later VMScluster
VMScluster
A VMScluster is a computer cluster involving a group of computers running the OpenVMS operating system. Whereas tightly coupled multiprocessor systems run a single copy of the operating system, a VMScluster is loosely coupled: each machine runs its own copy of OpenVMS, but the disk storage, lock...

), where multiple systems share disk storage, processing, job queues and print queues, and are connected either by specialized hardware or an industry-standard LAN
Local area network
A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...

 (usually Ethernet
Ethernet
Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

). A LAN-based cluster is often called a LAVc, for Local Area Network VMScluster, and allows, among other things, bootstrapping a possibly diskless satellite node over the network using the system disk of a bootnode.

VAXcluster support was first added in VMS version 4, which was released in 1984. This version only supported clustering over CI. Later releases of version 4 supported clustering over LAN (LAVC), and support for LAVC was improved in VMS version 5, released in 1988.

Mixtures of cluster interconnects and technologies are permitted, including Gigabit (GbE) Ethernet, SCSI, FDDI, DSSI
Digital Storage Systems Interconnect
The Digital Storage Systems Interconnect is a bus developed by Digital Equipment Corporation for connecting storage devices and clustering VAX systems and support was extended to MIPS based DECsystem and later to Alpha processor based AlphaServer systems.It was introduced in 1988 and has a...

, CI and Memory Channel adapters.

OpenVMS supports up to 96 nodes in a single cluster, and allows mixed-architecture clusters, where VAX and Alpha systems, or Alpha and Itanium systems can co-exist in a single cluster (Various organizations have demonstrated triple-architecture clusters and cluster configurations with up to 150 nodes, but these configurations are not supported by HP).

Unlike many other clustering solutions, VAXcluster offers transparent and fully distributed read-write with record-level locking, which means that the same disk and even the same file can be accessed by several cluster nodes at once; the locking occurs only at the level of a single record of a file, which would usually be one line of text or a single record in a database. This allows the construction of high-availability multiply redundant database servers.

Cluster interconnections can span upwards of 500 miles, allowing member nodes to be located in different buildings on an office campus, or in different cities.

Host-based volume shadowing allows volumes (of the same or of different sizes) to be shadowed (mirrored) across multiple controllers and multiple hosts, allowing the construction of disaster-tolerant environments.

Full access into the distributed lock manager
Distributed lock manager
A distributed lock manager provides distributed software applications with a means to synchronize their accesses to shared resources....

 (DLM) is available to application programmers, and this allows applications to coordinate arbitrary resources and activities across all cluster nodes. This obviously includes file-level coordination, but the resources and activities and operations that can be coordinated with the DLM are completely arbitrary.

With the supported capability of rolling upgrades and with multiple system disks, cluster configurations can be maintained on-line and upgraded incrementally. This allows cluster configurations to continue to provide application and data access while a subset of the member nodes are upgraded to newer software versions.

For general details, see the OpenVMS Cluster SPD. For more specific details, see the clustering-related manuals in the OpenVMS documentation set.

File system



OpenVMS has a very feature-rich file system
File system
A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...

, with support for stream and record-oriented IO, ACLs
Access control list
An access control list , with respect to a computer file system, is a list of permissions attached to an object. An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects. Each entry in a typical ACL specifies a subject...

, and file versioning. The typical user and application interface into the file system is the RMS
Record Management Services
Record Management Services are procedures in the VMS, RSTS/E, RT-11 and high-end RSX-11 operating systems that programs may call to process files and records within files. VMS RMS is an integral part of the system software; its procedures run in executive mode...

.

Details are in the RMS Utilities and RMS programming manuals, and in the I/O User's Reference Manual, all part of the OpenVMS documentation set. Also see the available ODS2 documentation, and the VMS File Systems Internals book, by Kirby McCoy, ISBN 1-55558-056-4.

Timekeeping


OpenVMS represents system time as the 64-bit number of 100 nanosecond
Nanosecond
A nanosecond is one billionth of a second . One nanosecond is to one second as one second is to 31.7 years.The word nanosecond is formed by the prefix nano and the unit second. Its symbol is ns....

 intervals (that is, ten million units per second; also known as a 'clunk') since the epoch
Epoch (reference date)
In the fields of chronology and periodization, an epoch is an instance in time chosen as the origin of a particular era. The "epoch" then serves as a reference point from which time is measured...

. The epoch of OpenVMS is midnight preceding November 17, 1858, which is the start of Modified Julian Day
Julian day
Julian day is used in the Julian date system of time measurement for scientific use by the astronomy community, presenting the interval of time in days and fractions of a day since January 1, 4713 BC Greenwich noon...

 numbering. The clock is not necessarily updated every 100 ns; for example, systems with a 100 Hz interval timer simply add 100 000 to the value every hundredth of a second. The operating system includes a mechanism to adjust for hardware timekeeping drift; when calibrated against a known time standard, it easily achieves an accuracy better than 0.01%. All OpenVMS hardware platforms derive timekeeping from an internal clock not associated with the AC supply power frequency.

While the system is shut down, time is kept by a Time-of-Year ("TOY") hardware clock. This clock keeps time to a lower resolution (perhaps 1 second) and generally, a lower accuracy (often 0.025% versus 0.01%). When the system is restarted, the VMS 64-bit time value is recomputed based on the time kept by the TOY clock and the last recorded year (stored on the system disk).

The 100 nanosecond granularity implemented within OpenVMS and the 63-bit absolute time representation (the sign bit indicates absolute time when clear and relative time when set) should allow OpenVMS trouble-free time computations up to 31-JUL-31086 02:48:05.47. At this instant, all clocks and time-keeping operations in OpenVMS will suddenly fail, since the counter will overflow and start from zero again.

Though the native OpenVMS time format can range far into the future, applications based on the C runtime library will likely encounter timekeeping problems beyond January 19, 2038 due to the Year 2038 problem
Year 2038 problem
The year 2038 problem may cause some computer software to fail at some point near the year 2038...

. Many components and applications may also encounter field-length-related date problems at year 10000 (see the Year 10,000 problem
Year 10,000 problem
The Year 10,000 problem is the class of all potential software bugs that would emerge when the need to express years with five digits arises...

).

Detailed information on time and timekeeping, and on daylight saving time and timezone differential factor operations, is contained in the OpenVMS FAQ.

Programming


The common language programming environment is described in the OpenVMS Calling Standard and the OpenVMS Programming Concepts manuals. This provides mixed-language calls, and a set of language-specific, run-time library (RTL), and system service routines. The language calls and the RTLs are implemented in user-mode shareable images, while the system services calls are generally part of the operating system, or part of privileged-mode code. This distinction between languages and RTLs and system services was once fairly clean and clear, but the implementations and specifics have become rather more murky over the years.

Various utilities and tools are integrated, as are various add-on languages and tools.

Many Programming Examples are available, see the pointers in the OpenVMS FAQ.

Debugging


The VMS Debugger supports all DEC compilers and many third party languages. It allows breakpoints, watchpoints and interactive runtime program debugging either using a command line or graphical
Graphical user interface
In computing, a graphical user interface is a type of user interface that allows users to interact with electronic devices with images rather than text commands. GUIs can be used in computers, hand-held devices such as MP3 players, portable media players or gaming devices, household appliances and...

 user interface. OpenVMS Debugger Manual

Common Language Environment


Among OpenVMS's notable features is the Common Language Environment, a strictly defined standard that specifies calling convention for functions and routines, including use of stack
Stack (data structure)
In computer science, a stack is a last in, first out abstract data type and linear data structure. A stack can have any abstract data type as an element, but is characterized by only three fundamental operations: push, pop and stack top. The push operation adds a new item to the top of the stack,...

s, register
Processor register
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are addressed by mechanisms other than main memory and can be accessed more quickly...

s, etc., independently of programming language. Because of this, it is possible to call a routine written in one language (e.g. Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...

) from another (e.g. COBOL
COBOL
COBOL is one of the oldest programming languages. Its name is an acronym for COmmon Business-Oriented Language, defining its primary domain in business, finance, and administrative systems for companies and governments....

), without needing to know the implementation details of the target language. OpenVMS itself is implemented in a variety of different languages (primarily BLISS
BLISS
BLISS is a system programming language developed at Carnegie Mellon University by W. A. Wulf, D. B. Russell, and A. N. Habermann around 1970. It was perhaps the best known systems programming language right up until C made its debut a few years later. Since then, C took off and BLISS faded into...

, VAX Macro
VAX Macro
VAX Macro is the computer assembly language implementing the instruction set for the line of CPUs designed to run the OpenVMS operating system created by Digital Equipment Corporation in 1977...

 and C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

) (per comp.os.vms newsgroup postings from members of HP OpenVMS Engineering), and the common language environment and calling standard supports freely mixing these languages, and Ada
Ada (programming language)
Ada is a structured, statically typed, imperative, wide-spectrum, and object-oriented high-level computer programming language, extended from Pascal and other languages...

, PL/I
PL/I
PL/I is a procedural, imperative computer programming language designed for scientific, engineering, business and systems programming applications...

, Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...

, BASIC
BASIC
BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....

, and others. This is in contrast to a system such as Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

, which is implemented nearly entirely in the C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

 language.

For details on these compilers and libraries, see the language manuals available at OpenVMS documentation.

Macro32 (an assembler on OpenVMS VAX, and a compiler on OpenVMS Alpha and on OpenVMS I64) is available within and integrated into OpenVMS. BLISS compilers are available for download from the OpenVMS Freeware, as are various ports of Perl, PHP
PHP
PHP is a general-purpose server-side scripting language originally designed for web development to produce dynamic web pages. For this purpose, PHP code is embedded into the HTML source document and interpreted by a web server with a PHP processor module, which generates the web page document...

, Ruby
Ruby (programming language)
Ruby is a dynamic, reflective, general-purpose object-oriented programming language that combines syntax inspired by Perl with Smalltalk-like features. Ruby originated in Japan during the mid-1990s and was first developed and designed by Yukihiro "Matz" Matsumoto...

 and other languages. Java is available from the HP Java website. C, Fortran and other languages are commercial products, and are available for purchase.

Security


OpenVMS provides various security features and mechanisms, including security identifiers, resource identifiers, subsystem identifiers, ACLs
Access control list
An access control list , with respect to a computer file system, is a list of permissions attached to an object. An ACL specifies which users or system processes are granted access to objects, as well as what operations are allowed on given objects. Each entry in a typical ACL specifies a subject...

, and detailed security auditing and alarms. Specific versions evaluated at DoD
United States Department of Defense
The United States Department of Defense is the U.S...

 NCSC Class C2 and, with the SEVMS security enhanced services support, at NCSC Class B1, per the NCSC Rainbow Series
Rainbow Series
The Rainbow Series is a series of computer security standards and guidelines published by the United States government in the 1980s and 1990s. They were originally published by the U.S...

. OpenVMS also holds an ITSEC E3 rating. For details on these ratings and the specific associated OpenVMS versions and ratings, see the NCSC and Common Criteria
Common Criteria
The Common Criteria for Information Technology Security Evaluation is an international standard for computer security certification...

 pages, and the associated product listings.

For details on the OpenVMS security mechanisms, see the HP OpenVMS Guide to System Security manual available at the OpenVMS documentation web site. Also see the OpenVMS security information.

Cross-platform applications


OpenVMS supports the following industry standard tools and applications:
  • Samba
    Samba (software)
    Samba is a free software re-implementation, originally developed by Andrew Tridgell, of the SMB/CIFS networking protocol. As of version 3, Samba provides file and print services for various Microsoft Windows clients and can integrate with a Windows Server domain, either as a Primary Domain...

     (CIFS)
  • Apache HTTP Server
    Apache HTTP Server
    The Apache HTTP Server, commonly referred to as Apache , is web server software notable for playing a key role in the initial growth of the World Wide Web. In 2009 it became the first web server software to surpass the 100 million website milestone...

  • Apache Tomcat
    Apache Tomcat
    Apache Tomcat is an open source web server and servlet container developed by the Apache Software Foundation...

  • Diskeeper
  • Zip/Unzip (Info-Zip)
  • GNU Privacy Guard
    GNU Privacy Guard
    GNU Privacy Guard is a GPL Licensed alternative to the PGP suite of cryptographic software. GnuPG is compliant with RFC 4880, which is the current IETF standards track specification of OpenPGP...

     (gpg)
  • Perl
    Perl
    Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...


Documentation


The OpenVMS operating documentation for various recent releases and for various core OpenVMS layered products is available online at the HP website http://www.hp.com/go/openvms/doc/.

Software Product Description (SPD) documents for many OpenVMS-related products (and for OpenVMS itself) are available at http://h18000.www1.hp.com/info/spd/. SPDs are introductory and legal descriptions of various products, listing the various supported capabilities and product features.

The OpenVMS Frequently Asked Questions (FAQ) contains information and pointers associated with OpenVMS, and is available in various formats at http://www.hoffmanlabs.org/vmsfaq/.

Releases, software support status


The current OpenVMS release are OpenVMS V8.4 for Alpha and Integrity servers, and OpenVMS V7.3 for VAX servers.

HP provides Current Version Support (CVS) and Prior Version Support (PVS) for various OpenVMS releases. The OpenVMS Roadmap guarantees PVS status for specific releases (V5.5-2, V5.5-2H4, V6.2, V6.2-1H3, V7.3-2) until 2012, and only then ending with 24 month's prior notice. CVS is provided for the current release and for the immediately prior release.

Applicable industry standards


The following are some of the industry standards claimed in the OpenVMS Software Product Description (SPD) document:
  • ANSI X3.4-1986: ASCII
    ASCII
    The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...

  • ANSI X3.22-1973/FIPS 3-1: Magtape, 800 BPI NRZI
  • ANSI X3.27-1987/FIPS 79: Magtape, Labels and Volume Structures
  • ANSI X3.39-1986/FIPS 25: Magtape, 1600 BPI PE
  • ANSI X3.40-1983: Magtape, unrecorded
  • ANSI X3.41-1974: ASCII 7-bit control sequences
  • ANSI X3.42-1975: Numeric values in character strings
  • ANSI X3.54-1986/FIPS 50: Magtape, 6250 BPI GCR
    Group Code Recording
    In computer science, group code recording refers to several distinct but related encoding methods for magnetic media. The first, used in 6250 cpi magnetic tape, is an error-correcting code combined with a run length limited encoding scheme...

  • ANSI X3.131-1986/ISO 9316(1989): SCSI
    SCSI
    Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...

    -1
  • ANSI X3.131-1994/ISO 10288(1994): SCSI-2
  • ANSI/IEEE 802.2
    IEEE 802.2
    IEEE 802.2 is the IEEE 802 standard defining Logical Link Control , which is the upper portion of the data link layer of the OSI Model. The LLC sublayer presents a uniform interface to the user of the data link service, usually the network layer...

    -1985: logical link control
  • ANSI/IEEE 802.3
    IEEE 802.3
    IEEE 802.3 is a working group and a collection of IEEE standards produced by the working group defining the physical layer and data link layer's media access control of wired Ethernet. This is generally a local area network technology with some wide area network applications...

    -1985: Ethernet CSMA/CD
  • FIPS 1-2: Code for Information Interchange; includes ANSI X3.4-1977(86)/FIPS 15; ANSI X3.32-1973/FIPS 36; ANSI X3.41-1974/FIPS 35; FIPS 7
  • FIPS 16-1/ANSI X3.15-1976: Serial Comms Bit Sequencing; FED STD 1010
  • FIPS 22-1/ANSI X3.1-1976: Synch signaling for DTE/DCE comms; FED STD 1013
  • FIPS 37/ANSI X3.36-1975: Synch High-Speed signaling for DTE/DCE comms; GIPS 1001
  • FIPS 86/ANSI X3.64-1979: Additional Controls for Use with ASCII
  • ISO 646: ISO 7-bit Coded Character Set for Information Exchange
  • ISO 1001: Magtape, Labels and Volume Structures
  • ISO 1863: Magtape, 800 BPI NRZI
  • ISO 1864: Magtape, unrecorded / NRZI and PE
  • ISO 2022: Code extensions for ISO 646
  • ISO 3307
    ISO 3307
    ISO 3307 is an international standard for date and time representations issued by the International Organization for Standardization . The standard was issued in 1975, then was superseded by ISO 8601 in 1988....

    : Time and Date Representations
  • ISO 3788: Magtape, 1600 BPI PE
  • ISO 4873: 8-Bit Character Codes
  • ISO 5652: Magtape, 6250 BPI GCR
  • ISO 6429: Control Sequences
  • ISO 9660
    ISO 9660
    ISO 9660, also referred to as CDFS by some hardware and software providers, is a file system standard published by the International Organization for Standardization for optical disc media....

    : CD-ROM volume and file structures

OpenVMS Hobbyist Program


Despite being a proprietary commercial operating system, in 1997 OpenVMS and a number of layered products were made available free of charge for hobbyist, non-commercial use as part of the OpenVMS Hobbyist Program. Since then, several companies producing OpenVMS software have made their products available under the same terms, such as Process Software and MVP Systems.

, the time required to obtain a hobbyist license was approximately one week from start to finish; from registration with a user group through acquisition of licenses and media. Hobbyist CD media is available for US$30, including international shipping. No anonymous FTP software downloads are available to hobbyists.

More information on the hobbyist program can be found at http://www.vmshobbyist.org/ and http://www.OpenVMS.org/. A number of hobbyist systems are open to the public, including the Deathrow Cluster.

Poetry Hacklab provides telnet and ssh access (username and password is luther) to two VAX/VMS machines located at the Freaknet Computer Museum.

Central OpenVMS-related topics


OpenVMS-related terms and acronyms include:
  • ACMS
    Application Control Management System
    Application Control Management System is a transaction processing monitor software system from HP for computers running the OpenVMS operating system....

     - Digital's transaction processing
    Transaction processing
    In computer science, transaction processing is information processing that is divided into individual, indivisible operations, called transactions. Each transaction must succeed or fail as a complete unit; it cannot remain in an intermediate state...

     (TP) system, often used with the DECdtm distributed transaction manager system service components of OpenVMS, and with the DECforms and Rdb
    Oracle Rdb
    Rdb/VMS is a relational database management system for the Hewlett-Packard OpenVMS operating system. It was originally created by Digital Equipment Corporation in 1984 as part of the VMS Information Architecture, intended to be used for data storage and retrieval by high-level languages and/or...

     products in applications with transactional requirements
  • Asynchronous system trap
    Asynchronous System Trap
    Asynchronous system trap refers to a mechanism used in several computer operating systems designed by the former Digital Equipment Corporation of Maynard, Massachusetts....

     (AST)
  • DECforms - Digital's successor to the Forms Management System
  • DECnet
    DECnet
    DECnet is a suite of network protocols created by Digital Equipment Corporation, originally released in 1975 in order to connect two PDP-11 minicomputers. It evolved into one of the first peer-to-peer network architectures, thus transforming DEC into a networking powerhouse in the 1980s...

     - Digital's proprietary networking architecture which also includes MOP
    Maintenance Operations Protocol
    The Maintenance Operation Protocol is used for utility services such as uploading and downloading system software, remote testing and problem diagnosis...

    .
  • DELTA
    Delta
    Delta commonly refers to:* Delta , Δ or δ in the Greek alphabet, also used as a mathematical symbol* River delta, a landform at the mouth of a river* Delta Air Lines, a major U.S...

     and XDELTA
    Xdelta
    xdelta is a command line program for delta encoding, which generates two file difference. This is similar to diff and patch, but it is targeted for binary files and does not generate human readable output....

     - OpenVMS debuggers
  • DIGITAL Command Language
    DIGITAL Command Language
    DCL, the DIGITAL Command Language, is the standard command languageadopted by most of the operating systems that were sold by the former Digital Equipment Corporation...

     (DCL) - Digital Command Language - command line interpreter.
  • DECwindows - Digital's implementation of the X Window System
    X Window System
    The X window system is a computer software system and network protocol that provides a basis for graphical user interfaces and rich input device capability for networked computers...

    .
  • Event flag
    Event flag
    An event flag is a process synchronization primitive in the OpenVMS operating system. It has two possible states, set or cleared. The following basic primitive operations are provided:* Set event flag * Clear event flag...

     - a simple synchronization mechanism
  • Files-11
    Files-11
    Files-11, also known as on-disk structure, is the file system used by Hewlett-Packard's OpenVMS operating system, and also by the older RSX-11...

     - low level filesystem
  • File Description Language (FDL) - defines file record/field structure
  • Forms Management System (FMS) - Digital's first generation language-independent Form driver
  • Local Area Transport
    Local Area Transport
    Local Area Transport is a non-routable networking technology developed by Digital Equipment Corporation to provide connection between the DECserver 90, 100, 200, 300, 500, 700 and DECserver 900 terminal servers and Digital's VAX and Alpha and MIPS_architecture host computers via Ethernet, giving...

     (LAT) - is a LAN-based non-routable communications protocol to support DEC and other Terminal Servers
  • QIO
    QIO
    QIO is a term used in several computer operating systems designed by the former Digital Equipment Corporation of Maynard, Massachusetts.I/O operations on these systems are initiated by issuing a QIO call to the kernel...

     Queued Input Output; the low-level I/O interface
  • Oracle Rdb
    Oracle Rdb
    Rdb/VMS is a relational database management system for the Hewlett-Packard OpenVMS operating system. It was originally created by Digital Equipment Corporation in 1984 as part of the VMS Information Architecture, intended to be used for data storage and retrieval by high-level languages and/or...

     - An SQL compliant relational database created by DEC but now owned by Oracle
  • Record Management Services
    Record Management Services
    Record Management Services are procedures in the VMS, RSTS/E, RT-11 and high-end RSX-11 operating systems that programs may call to process files and records within files. VMS RMS is an integral part of the system software; its procedures run in executive mode...

     (RMS) - high-level, language/device-independent Input/output
    Input/output
    In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...

  • Runtime libraries (RTL) - shared routines and functions, callable from any language
  • OpenVMS Galaxy - co-habitating OpenVMS installations; a form of system partitioning
  • OpenVMS Clusters - for redundancy, incremental hardware upgrades, or disaster tolerance
  • System 1032 (S1032) - A high-performance database management system and application development environment designed to support the OpenVMS user community. Used at some companies in the 1980s and 90s, but, in little use today.
  • XQP - the eXtended QIO Processor (XQP), which implements the Files-11 filesystem.


For information on layered products, see the Software Product Description (SPD) for the product. For OpenVMS components, see the OpenVMS documentation set.

See also

  • Comparison of operating systems
    Comparison of operating systems
    These tables compare general and technical information for a number of widely used and currently available operating systems.Because of the large number and variety of available Linux distributions, they are all grouped under a single entry; see comparison of Linux distributions for a detailed...

  • SRM
    System Reference Manual
    The SRM firmware is the boot firmware written by Digital Equipment Corporation for computer systems based on the Alpha AXP microprocessor...

     — The boot firmware
    Firmware
    In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...

     required to boot OpenVMS on DEC Alpha
    DEC Alpha
    Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...

    -based computer systems [ftp://ftp.digital.com/pub/DEC/Alpha/firmware/index.html]
  • EFI
    Extensible Firmware Interface
    The Unified Extensible Firmware Interface is a specification that defines a software interface between an operating system and platform firmware...

     — the boot firmware
    Firmware
    In electronic systems and computing, firmware is a term often used to denote the fixed, usually rather small, programs and/or data structures that internally control various electronic devices...

     used by OpenVMS on Itanium
    Itanium
    Itanium is a family of 64-bit Intel microprocessors that implement the Intel Itanium architecture . Intel markets the processors for enterprise servers and high-performance computing systems...

     platforms http://www.hoffmanlabs.com/openvms/hwi64.shtml
  • FreeVMS
    FreeVMS
    FreeVMS is a free software clone of the VMS computer operating system, licensed under the terms of the GNU General Public License. As of 2010, the project is in the early stages of development...

     — A software project aiming to create a GPLed clone of VMS http://www.freevms.net/
  • Paris Métro Line 14
    Paris Metro Line 14
    Line 14 of the Paris Métro system connects the stations Saint Lazare and Olympiades on a north-west south-east diagonal across the centre of Paris. It is the twelfth busiest of sixteen lines on the network, and as of 2011, the only one to be operated completely automatically; the second such line...

     — A notable OpenVMS client http://www.adahome.com/Ammo/Success/subway.html
  • Indian Railways
    Indian Railways
    Indian Railways , abbreviated as IR , is a departmental undertaking of Government of India, which owns and operates most of India's rail transport. It is overseen by the Ministry of Railways of the Government of India....

     — another (very) large OpenVMS client http://h71000.www7.hp.com/openvms/brochures/indiarr/indiarr.pdf
  • Terry Shannon — late advocate of OpenVMS http://www.shannonknowshpc.com/

OpenVMS publications

  • The Minimum You Need to Know to Be an OpenVMS Application Developer, Roland Hughes, ISBN 978-0-977866-0-3 http://www.theminimumyouneedtoknow.com/app_book.html
  • The Minimum You Need to Know About Java on OpenVMS, Roland Hughes, ISBN 978-0-9770866-1-0 http://www.theminimumyouneedtoknow.com/about_java_on_openvms.html
  • The Minimum You Need to Know About Service Oriented Architecture, Roland Hughes, ISBN 978-0-9770866-6-5 http://www.theminimumyouneedtoknow.com/service_oriented_architecture_book.html
  • Getting Started with OpenVMS, Michael D. Duffy, ISBN 1-55558-279-6
  • Getting Started with OpenVMS System Management, 2nd Edition, David Donald Miller, Stephen Hoffman, Lawrence Baldwin, ISBN 1-55558-243-5
  • Introduction to OpenVMS, 5th Edition, Lesley Ogilvie Rice, ISBN 1-55558-194-3
  • Introduction to OpenVMS, David W Bynon, ISBN 1-878956-61-2
  • OpenVMS Alpha Internals and Data Structures: Memory Management, Ruth Goldenberg, ISBN 1-55558-159-5
  • OpenVMS Alpha Internals and Data Structures : Scheduling and Process Control : Version 7.0, Ruth Goldenberg, Saro Saravanan, Denise Dumas, ISBN 1-55558-156-0
  • OpenVMS online documentation
  • OpenVMS Performance Management, Joginder Sethi, ISBN 1-55558-126-9
  • OpenVMS System Management Guide, Lawrence Baldwin, ISBN 1-55558-143-9
  • The OpenVMS User's Guide, Second Edition, Patrick Holmay, ISBN 1-55558-203-6
  • Using DECwindows Motif for OpenVMS, Margie Sherlock, ISBN 1-55558-114-5
  • VAX/VMS Internals and Data Structures: Version 5.2 ("IDSM"), Ruth Goldenberg, Saro Saravanan, Denise Dumas, ISBN 1-55558-059-9
  • Writing OpenVMS Alpha Device Drivers in C, Margie Sherlock, Leonard Szubowicz, ISBN 1-55558-133-1
  • Writing Real Programs in DCL, second edition, Stephen Hoffman, Paul Anagnostopoulos, ISBN 1-55558-191-9

External links