What is VSE Operating System?
VSE (Virtual Storage Extended) is an operating system for IBM mainframe computers, used for traditional batch and online transaction processing applications. It features online transaction processing, security, and connectivity that easily integrates into a heterogeneous environment using web-based business solutions.
It can be used alone or in a heterogeneous environment. Flexible integration is possible because it uses open and industry standards. VSE enables clients to extend existing solutions with connectors to access applications on Linux on IBM Z or any other platform and to access z/VSE resources from other platforms.
History of VSE Operating System
The latest one is in the DOS/360 family, which originated in 1965. Announced February 1, 2005, by IBM as successor to VSE/ESA 2.7, then new VSE was named to reflect the new “System z” branding for IBM’s mainframe product line.
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. DOS/360 originally used 24-bit addressing. As the underlying hardware evolved, VSE/ESA acquired 31-bit addressing capability.
It is less common than prominent z/OS and is mostly used on smaller machines. In the late 1980s, VSE customers expressed widespread perception that IBM planned to discontinue VSE and migrate its customers to MVS. However, IBM relented and agreed to continue to produce new versions of VSE.
IBM released z/VSE Version 4, which requires 64-bit 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. The latest shipping release is z/VSE 6.2.0 – available since December 2017, including the new CICS Transaction Server for z/VSE 2.2.
Devices Support by VSE
VSE can use ECKD, FBA, and SCSI devices. Fiber Channel access to SCSI storage devices was initially available on 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.
User Interfaces
VSE operating system provides the following user interfaces, such as:
1. Job Control Language (JCL)
A Job Control Language (JCL) that continues in the positional-parameter orientation of earlier DOS systems is z/VSE’s batch processing primary user interface. There is also another special interface for system console operators.
2. yond batch
VSE, like z/OS systems, had traditionally provided 3270 terminal user interfaces. However, most z/VSE installations have at least begun to add Web browser access to z/VSE applications. VSE’s TCP/IP 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. One TCP/IP stack provides IPv4 communication only, the other IPv4 and IPv6 communication. In addition to the commercially available TCP/IP stacks for VSE, 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.
The z/VSE system can fully exploit the native Linux TCP/IP stack using this method.
IBM recommends that z/VSE customers run Linux on IBM Z 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. CICS, one of the most popular enterprise transaction processing systems, is extremely popular among z/VSE users and now implements recent innovations such as Web services. DB2 is also available and popular.
VSE Older Versions
- The last VSE/ESA release, VSE/ESA 2.7, has no longer been supported since February 28, 2007.
- VSE 3.1 was the last release that was compatible with 31-bitmainframes, as opposed to VSE Version 4, 5, and 6. VSE 3.1 was supported in 2009.
- VSE Version 4 has been no longer supported since October 2014 (end of service for z/VSE 4.3).