Transaction Processing Facility

z/TPF

Developer	IBM
Written in	z/Architecture Assembly language, C, C++
OS family	z/Architecture assembly language (z/TPF), ESA/390 assembly language (TPF4)
Working state	Current
Source model	Closed source (Source code is available to licensed users with restrictions)
Initial release	1979; 45 years ago (1979)
Latest release	1.1.0.2023[1]
Platforms	IBM System z (z/TPF), ESA/390 (TPF4)
Kernel type	Real-time
Default user interface	3215 3270
License	Proprietary monthly license charge (MLC)
Official website	z/TPF Product Page

Transaction Processing Facility (TPF)^[2] is an IBM real-time operating system for mainframe computers descended from the IBM System/360 family, including zSeries and System z9.

TPF delivers fast, high-volume, high-throughput transaction processing, handling large, continuous loads of essentially simple transactions across large, geographically dispersed networks.

While there are other industrial-strength transaction processing systems, notably IBM's own CICS and IMS, TPF's specialty is extreme volume, large numbers of concurrent users, and very fast response times. For example, it handles VISA credit card transaction processing during the peak holiday shopping season.^[3][2]

The TPF passenger reservation application PARS, or its international version IPARS, is used by many airlines. PARS is an application program; TPF is an operating system.

One of TPF's major optional components is a high performance, specialized database facility called TPF Database Facility (TPFDF).^[4]

A close cousin of TPF, the transaction monitor ALCS, was developed by IBM to integrate TPF services into the more common mainframe operating system MVS, now z/OS.