computer science

IBM TPNS

IBM TPNS is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand IBM TPNS rather than just read about it. In short: Teleprocessing Network Simulator (TPNS) is an IBM licensed program, first released in 1976 as a test automation tool to simulate the end-user activity of network terminal(s) to a mainframe computer system, for functional testing, regression testing, system testing, capacity management, benchmarking and stress testing. In 2002, IBM re-packaged TPNS and released Workload Simulator for z/OS and S/390 (WSim) as a succes…

Key takeaways

IBM TPNS belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect IBM TPNS to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IBM TPNS from memory before moving on to harder problems.

Reference excerpt

Teleprocessing Network Simulator (TPNS) is an IBM licensed program, first released in 1976 as a test automation tool to simulate the end-user activity of network terminal(s) to a mainframe computer system, for functional testing, regression testing, system testing, capacity management, benchmarking and stress testing. In 2002, IBM re-packaged TPNS and released Workload Simulator for z/OS and S/390 (WSim) as a successor product.

History Teleprocessing Network Simulator (TPNS) Version 1 Release 1 (V1R1) was introduced as Program Product 5740-XT4 in February 1976, followed by four additional releases up to V1R5 (1981). In August 1981, IBM announced TPNS Version 2 Release 1 (V2R1) as Program Product 5662-262, followed by three additional releases up to V2R4 (1987). In January 1989, IBM announced TPNS Version 3 Release 1 (V3R1) as Program Product 5688-121, followed by four additional releases up to V3R5 (1996). In December 1997, IBM announced a TPNS V3R5 Service Level 9711 Functional and Service Enhancements release. In September 1998, IBM announced the TPNS Test Manager (for TPNS V3R5) as a usability enhancement to automate the test process further in order to improve productivity through a logical flow, and to streamline TPNS-based testing of IBM 3270 applications or CPI-C transaction programs. In December 2001, IBM announced a TPNS V3R5 Service Level 0110 Functional and Service Enhancements release. In August 2002, IBM announced Workload Simulator for z/OS and S/390 (WSim) V1.1 as Program Number 5655-I39, a re-packaged successor product to TPNS, alongside the WSim Test Manager V1.1, a re-packaged successor to the TPNS Test Manager. In November 2012, IBM announced a maintenance update of Workload Simulator for z/OS and S/390 (WSim) V1.1, to simplify the installation of updates to the product. In December 2015, IBM announced enhancements to Workload Simulator for z/OS and S/390 (WSim) V1.1, providing new utilities for TCP/IP data capture and script generation.

Features

Simulation support

Teleprocessing Network Simulator (TPNS) TPNS supports the simulation of a wide range of networking protocols and devices: SNA/SDLC, start-stop, BSC, TWX, TTY, X.25 Packet Switching Network, Token Ring Local Area Networking, and TCP/IP servers and clients (Telnet 3270 & 5250, Telnet Line Mode Network Virtual Terminal, FTP and simple UDP clients). TPNS can also simulate devices using the Airline Line Control (ALC) and the HDLC protocols. The full implementation of SNA in TPNS enables it to simulate all LU types (including LU6.2 and CPI-C), PU types (including PU2.1), and SSCP functions. Finally, TPNS also provides extensive user exit access to its internal processes to enable the simulation of user-defined (home-grown) line disciplines, communications protocols, devices (terminals and printers) and programs. TPNS is therefore the appropriate test tool for installations that need to test:

either the entire system configuration path of hardware and software components, from the teleprocessing line interface (modem, for example) all the way to the subsystem (CICS, IMS, DB2, TSO/ISPF, etc.), the application and finally to the file or database record (disk I/O) and back; Note: In this configuration, TPNS transmits its generated data traffic from its MVS address space, first across a channel-adapter to its TPNS Control Program (TPNCP) running in a dedicated IBM 37x5 Communications Controller, and then across teleprocessing lines connected back-to-back between the TPNCP and the target IBM 37x5 channel-attached to the host system (server) under test and its subsystems, applications and databases/files. or only application systems and their hardware and software components, from the networking access method API (either the VTAM API or the TCP/IP High Performance Native Sockets, or Macro, API) to the subsystem (CICS, IMS, DB2, TSO/ISPF, etc.), the application and finally to the file or database record (disk I/O) and back; Note: In this configuration, TPNS transmits its generated data traffic from its MVS address space to the target application directly across the networking access method's API and does not, therefore, require a dedicated IBM 37x5 Communications Controller to run its TPNCP, or any other networking hardware and software components except the networking access method (VTAM or IBM TCP/IP for MVS) that already runs in—or is already network-connected to—the host system (server) under test. or both.

Workload Simulator for z/OS and S/390 (WSim) WSim fully supports a subset of TPNS-simulated devices and programmed resources: CPI-C, TCP/IP servers and clients (Telnet 3270 & 5250, Telnet Line Mode Network Virtual Terminal, FTP and simple UDP clients), and SNA LU simulation. WSim relies solely on software interfaces to communicate with the system under test. WSim is therefore the appropriate test tool for installations that need to test application systems and their hardware and software components, from the networking access method API (either the VTAM API or the TCP/IP High Performance Native Sockets, or Macro, API) to the subsystem (CICS, IMS, DB2, TSO/ISPF, etc.), the application and finally to the file or database record (disk I/O) and back; that is to say, without the need to install any networking hardware and software components except the networking access method (VTAM or IBM TCP/IP for MVS) that already runs in—or is already network-connected to—the host system (server) under test.

Other uses In addition to its use as a test tool exchanging message traffic with a system under test, TPNS/Wsim has been deployed:

as a systems management tool — to monitor the availability of an online system, from the end-user's perspective; as a software development tool — for prototyping software programs during the development process.

Scripting languages

TPNS language TPNS initially provided its own 'TPNS language', a high-level, macro assembler-like language with programming statements and operands that a test programmer would use to define:

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with IBM TPNS

Start with the simplest possible case. Write down what IBM TPNS claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to IBM TPNS before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about IBM TPNS ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of IBM TPNS

In research: IBM TPNS appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses IBM TPNS in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: IBM TPNS is common in secondary-school and first-year university syllabi. It links to neighbouring topics IBM mainframe software, IBM software, Load testing tools, so understanding it makes those chapters shorter.
In everyday life: Look for IBM TPNS outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study IBM TPNS in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IBM TPNS means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain IBM TPNS out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IBM TPNS in simple terms?

Why does IBM TPNS matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study IBM TPNS?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on IBM TPNS.