computer science

IBM 7090/94 IBSYS

IBM 7090/94 IBSYS 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 7090/94 IBSYS rather than just read about it. In short: IBSYS is a discontinued tape-based operating system that IBM supplied with its IBM 709, IBM 7090 and IBM 7094 computers, and a significantly different, though similar operating system provided with IBM 7040 and IBM 7044 computers. IBSYS was based on FORTRAN Monitor System (FMS) and (more likely) Bell Labs' "BESYS" rather than the SHARE Operating System.

Key takeaways

IBM 7090/94 IBSYS 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 7090/94 IBSYS to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IBM 7090/94 IBSYS from memory before moving on to harder problems.

Reference excerpt

IBSYS is a discontinued tape-based operating system that IBM supplied with its IBM 709, IBM 7090 and IBM 7094 computers, and a significantly different, though similar operating system provided with IBM 7040 and IBM 7044 computers. IBSYS was based on FORTRAN Monitor System (FMS) and (more likely) Bell Labs' "BESYS" rather than the SHARE Operating System. IBSYS directly supported several older computer language compilers and assemblers on the $EXECUTE card: 9PAC, FORTRAN and IBSFAP. Newer language processors ran under IBJOB. IBM later provided similar facilities for the 7040/7044 as IBM 7040/7044 Operating System (16K/32K) 7040-PR-150 and for the IBM 1410/IBM 7010 as IBM 1410/7010 Operating System 1410-PR-155.

IBSYS System Supervisor IBSYS itself is a resident monitor program, that reads control card images placed between the decks of program and data cards of individual jobs. An IBSYS control card begins with a "$" in column 1, immediately followed by a Control Name that selects the various IBSYS utility programs needed to set up and run the job. These card deck images are usually read from magnetic tapes prepared offline, not directly from the card reader.

IBJOB Processor The IBJOB Processor is a subsystem that runs under the IBSYS System Supervisor. It reads control cards that request, e.g., compilation, execution. The languages supported include COBOL. Commercial Translator (COMTRAN), Fortran IV (IBFTC) and Macro Assembly Program (IBMAP).

See also University of Michigan Executive System Timeline of operating systems

Further reading Noble, A. S. Jr., "Design of an integrated programming and operating system", IBM Systems Journal, June 1963. "The present paper considers the underlying design concepts of IBSYS/IBJOB, an integrated programming and operating system. The historical background and over-all structure of the system are discussed. Flow of jobs through the IBJOB processor, as controlled by the monitor, is also described." "IBM 7090/7094 IBSYS Operating System Version 13 System Monitor (IBSYS)", Form C28-6248-7 "IBM 7090/7094 IBSYS Operating System Version 13 IBJOB Processor", Form C28-6389-1 "IBM 7090/7094 IBSYS Operating System Version 13 IBJOB Processor Debugging Package", Form C28-6393-2

Notes

External links IBM 7090/94 IBSYS Operating System, Jack Harper Dave Pitts' IBM 7090 support IBSYS source archived with Bitsavers History of FORTRAN and FORTRAN II – FORTRAN II and other software running on IBSYS, Software Preservation Group, Computer History Museum

Worked examples

Example 1 — a first encounter with IBM 7090/94 IBSYS

Start with the simplest possible case. Write down what IBM 7090/94 IBSYS 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 7090/94 IBSYS 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 7090/94 IBSYS 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 7090/94 IBSYS

In research: IBM 7090/94 IBSYS 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 7090/94 IBSYS 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 7090/94 IBSYS is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1960 software, Discontinued operating systems, IBM 700/7000 series, so understanding it makes those chapters shorter.
In everyday life: Look for IBM 7090/94 IBSYS 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 7090/94 IBSYS in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IBM 7090/94 IBSYS 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 7090/94 IBSYS out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IBM 7090/94 IBSYS in simple terms?

Why does IBM 7090/94 IBSYS 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 7090/94 IBSYS?

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 7090/94 IBSYS.