computer science

IBM 1401 Symbolic Programming System

IBM 1401 Symbolic Programming System 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 1401 Symbolic Programming System rather than just read about it. In short: The IBM 1401 Symbolic Programming System (SPS) was an assembler that was developed by Gary Mokotoff, IBM Applied Programming Department, for the IBM 1401 computer, the first of the IBM 1400 series. One source indicates that "This programming system was announced by IBM with the machine." SPS-1 could run on a low-end machine with 1.4K memory, SPS-2 required at least 4K memory.

Key takeaways

IBM 1401 Symbolic Programming System 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 1401 Symbolic Programming System to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IBM 1401 Symbolic Programming System from memory before moving on to harder problems.

Reference excerpt

The IBM 1401 Symbolic Programming System (SPS) was an assembler that was developed by Gary Mokotoff, IBM Applied Programming Department, for the IBM 1401 computer, the first of the IBM 1400 series. One source indicates that "This programming system was announced by IBM with the machine." SPS-1 could run on a low-end machine with 1.4K memory, SPS-2 required at least 4K memory.

SPS-1 punched one card for each input instruction in its first pass and this deck had to be read during pass 2. At the University of Chicago and many other locations, SPS-1 was replaced by assemblers taking advantage of the commonly available 4K memory configuration to pack the output of pass one into several instructions per card. Other assemblers were written which placed the pass one output into memory for small programs. As the 1400 series matured additional assemblers, programming languages and report generators became available, replacing SPS in most sites.

See also Autocoder FARGO (programming language)

References

External links IBM 1401 Symbolic Programming Systems: SPS-1 and SPS-2, C20-1480-0 "1401s I have known" by Tom Van Vleck includes a description of an operating environment including 1401 SPS machines. Gary Mokotoff Collection of IBM 1401 Program Listings, 1959-1961

Worked examples

Example 1 — a first encounter with IBM 1401 Symbolic Programming System

Start with the simplest possible case. Write down what IBM 1401 Symbolic Programming System 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 1401 Symbolic Programming System 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 1401 Symbolic Programming System 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 1401 Symbolic Programming System

In research: IBM 1401 Symbolic Programming System 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 1401 Symbolic Programming System 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 1401 Symbolic Programming System is common in secondary-school and first-year university syllabi. It links to neighbouring topics Assembly languages, IBM software, Programming language topic stubs, so understanding it makes those chapters shorter.
In everyday life: Look for IBM 1401 Symbolic Programming System 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 1401 Symbolic Programming System in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IBM 1401 Symbolic Programming System 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 1401 Symbolic Programming System out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IBM 1401 Symbolic Programming System in simple terms?

Why does IBM 1401 Symbolic Programming System 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 1401 Symbolic Programming System?

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 1401 Symbolic Programming System.