VSEⁿ (''Virtual Storage Extended'') is an

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

for

IBM mainframe IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the computer market with the 7000 series and the later System/360, followed by the System/370. Current mainframe computers in IBM' ...

computers, the latest one in the DOS/360 lineage, which originated in 1965. It is less common than

z/OS z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest: ...

and is mostly used on smaller machines. DOS/VSE was introduced in 1979 as a successor to DOS/VS; in turn, DOS/VSE was succeeded by VSE/SP version 1 in 1983, and VSE/SP version 2 in 1985. In the late 1980s, there was a widespread perception among VSE customers that IBM was planning to discontinue VSE and migrate its customers to MVS instead, although IBM relented and agreed to continue to produce new versions of VSE. In February 2005, IBM announced z/VSE as successor to VSE/ESA 2.7, which was named to reflect the new System z branding for IBM's mainframe product line. In June 2021, 21st Century Software Inc announced that it had licensed the z/VSE source code from IBM with the intention of developing new versions of the operating system. As part of this transfer, z/VSE was renamed to VSEⁿ.

Overview

DOS/360 originally used

24-bit Notable 24-bit machines include the CDC 924 – a 24-bit version of the CDC 1604, CDC lower 3000 series, SDS 930 and SDS 940, the ICT 1900 series, the Elliott 4100 series, and the Datacraft minicomputers/ Harris H series. The term SWORD ...

addressing. As the underlying hardware evolved, VSE/ESA acquired 31-bit addressing capability. IBM released z/VSE Version 4, which requires

64-bit In computer architecture, 64-bit integers, memory addresses, or other data units are those that are 64 bits wide. Also, 64-bit central processing units (CPU) and arithmetic logic units (ALU) are those that are based on processor registers, a ...

z/Architecture z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architecture ...

hardware and can use 64-bit real mode addressing, in 2007. With z/VSE 5.1 (available since 2011) z/VSE introduced 64-bit virtual addressing and memory objects (chunks of virtual storage), that are allocated above 2 GB.

User interfaces

Job Control Language (JCL)

Job Control Language Job Control Language (JCL) is a scripting language used on IBM mainframe operating systems to instruct the system on how to run a batch processing, batch job or start a subsystem. The purpose of JCL is to say which programs to run, using which fi ...

(JCL) that continues in the positional-parameter orientation of earlier DOS systems is VSEⁿ's

batch processing Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically ...

primary user interface. There is also another, special interface for

system console A computer terminal is an electronic or electromechanical computer hardware, hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. Most early computers only had a front panel to ...

operators.

Beyond batch

VSEⁿ, like z/OS systems, had traditionally provided 3270 terminal user interfaces. However, most VSEⁿ installations have at least begun to add

Web browser A web browser, often shortened to browser, is an application for accessing websites. When a user requests a web page from a particular website, the browser retrieves its files from a web server and then displays the page on the user's scr ...

access to VSEⁿ applications. VSEⁿ's

TCP/IP The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are ...

is a separately priced option for historic reasons, and is available in two different versions from two vendors. Both vendors provide a full function TCP/IP stack with applications, such as telnet and

FTP The File Transfer Protocol (FTP) is a standard communication protocol used for the transfer of computer files from a server to a client on a computer network. FTP is built on a client–server model architecture using separate control and dat ...

. One TCP/IP stack provides IPv4 communication only, the other IPv4 and IPv6 communication. In addition to the commercially available TCP/IP stacks for VSEⁿ, IBM also provides the Linux Fastpath method which uses IUCV socket or Hipersockets connections to communicate with a Linux guest, also running on the mainframe. Using this method the VSEⁿ system is able to fully exploit the native Linux TCP/IP stack. IBM recommends that z/VSE customers run

Linux on IBM Z Linux ( ) is a family of open source Unix-like operating systems based on the Linux kernel, an kernel (operating system), operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically package manager, pac ...

alongside, on the same physical system, to provide another 64-bit application environment that can access and extend z/VSE applications and data via Hipersockets using a wide variety of

middleware Middleware is a type of computer software program that provides services to software applications beyond those available from the operating system. It can be described as "software glue". Middleware makes it easier for software developers to imple ...

CICS IBM CICS (Customer Information Control System) is a family of mixed-language application servers that provide online business transaction management, transaction management and connectivity for applications on IBM mainframe systems under z/OS ...

, one of the most popular enterprise

transaction processing system A transaction processing system (TPS) is a computer software, software system, or software/computer hardware, hardware combination, that supports transaction processing. History The first transaction processing system was Sabre (computer system), ...

s, is extremely popular among VSEⁿ users and now implements recent innovations such as

Web services A web service (WS) is either: * a service offered by an electronic device to another electronic device, communicating with each other via the Internet, or * a server running on a computer device, listening for requests at a particular port over a n ...

. Db2 is also available and popular.

Device support

VSEⁿ can use ECKD, FBA and SCSI devices.

Fibre Channel Fibre Channel (FC) is a high-speed data transfer protocol providing in-order, lossless delivery of raw block data. Fibre Channel is primarily used to connect computer data storage to Server (computing), servers in storage area networks (SAN) in ...

access to SCSI storage devices was initially available on z/VSE 3.1 on a limited basis (including on IBM's Enterprise Storage Server (ESS), IBM System Storage DS8000, DS6000 series), but the limitations disappeared with 4.2 (thus including IBM Storwize V7000, V5000, V3700 and V9000).

References

External links

VSEⁿ website
{{DEFAULTSORT:VSE IBM mainframe operating systems