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An IBM mainframe occurs as big, high-vet computer processed by International Business Machines (IBM). Mainframe computers traditionally are expensive, physically big, & use at times high transaction processing and I/O performance, but are non when expensive & high-performance when supercomputers.

Description

From either 1950 to 1965, IBM and many more corporations made many computer system, virtually all of which were incompatible by having every more. IBM got ii exemplary categories: 1 for even commercial message or information processing apply, & 1 for engineering & scientific utilize. Them categories were largely incompatible by owning every more, & there were incompatibilities possibly in every category. Completely that changed sustaining a announcement of the System/360 (S/360) in April, 1964. A System/360 was one series of compatible system for each commercial message & scientific have. A System/360 afterwards evolved into a System/370, the System/390, the zSeries, and a System z9.

System/360 (suggesting a "360 degree", or "all-around" adp system) incorporated features which got antecedently been present in exclusively either a commercial message line (like decimal arithmetic & byte addressing) or even a technical indicator line (like floating point arithmetic).

Notable pre-System/360 IBM mainframes involved: IBM 650 (business/data processing) IBM 704 (science/engineering) IBM 1401 (business/data processing) IBM 7090 (science/engineering)

Software

Operating systems
A primary operating systems inside have in IBM mainframes include z/OS (which followed MVS and OS/390), z/VM (previously VM/CMS), z/VSE, z/TPF, and Linux on zSeries. Two or three systems however start MUSIC/SP, another operating models. Former operating systems for the System/360 family and its successors involved OS/360 (with PCP, MFT, & MVT), BOS, TOS, DOS, and SVS. There are programs-depending ape for the System/370, System/390, zSeries, and System z9 hardware, including FLEX-ES and the freely available Hercules emulator which runs under Linux & Microsoft Windows. A original OS/360 and early MVS and VM/CMS versions have been freed free of charge apply.

Middleware
IBM mainframes do all the major enterprise transaction processing environments and databases, including CICS, IMS, WebSphere Application Server, DB2, and Oracle. Within several lawsuits these software subsystems can redo in additional than a single mainframe operating technique.

Notes

A bit of of the arithmetical units & addressing features were optional in a few system of the System/360. Notwithstanding, system were upward compatible & virtually all were likewise downwards compatible.

Devices memory protection was provided to protect a operating formulas from either either a user software download (tasks) & a user tasks from every more.

Nowadays dated. For details on the important 64-bit architectural changes, refer to IBM technical indicator publications (understand z/Architecture).

RACF Update Journal
Xephon's quarterly technical journal covering RACF and related security considerations. RACF is IBM's access control software for z/OS and z/VM. Older issues, including published code, available for free download. Click on RACF Links for Xephon's favorite Top 10 Web links.

WAVV: World Alliance of VSE and VM
User group spun off from GUIDE in 1995 and similar to SHARE, with annual conference aimed mainly at VSE/ESA and z/VM systems programmers.

TPF: Transaction Processing Facility
IBM home page for TPF. Despite the name, TPF can be run as a stand-alone operating system on IBM mainframes.

Operating Systems for IBM Mainframe Servers
IBM starting point for mainframe OSs. Links to home page of each OS, with brief descriptions: z/OS, z/OS.e, Linux on zSeries, z/VM, TPF and z/VSE.

Sysprog.net
News, programming tips and technical information for z/OS and mainframe Linux applications and systems programmers.

Linux on zSeries
IBM home page for Linux on the eserver zSeries (mainframe).

NaSPA: Network and Systems Professionals Association
User group. Primary focus is z/OS systems programming.

Mainframe Programming
Categorized page of links for IBM mainframe programmers.

Mainframes.com
Mainframe programming information, including a large dictionary and links to downloads and manuals.

TCP/SNA Update home page
Xephon's quarterly technical journal covering TCP/IP and SNA on the mainframe. Older issues, including published code, available for free download. Click on TCP Links for Xephon's favorite Top 10 Web links.

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