computer science

IBM System/360 Model 195

IBM System/360 Model 195 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 System/360 Model 195 rather than just read about it. In short: The IBM System/360 Model 195 is a discontinued IBM computer introduced on August 20, 1969. The Model 195 was a reimplementation of the IBM System/360 Model 91 design using monolithic integrated circuits.

Key takeaways

IBM System/360 Model 195 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 System/360 Model 195 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of IBM System/360 Model 195 from memory before moving on to harder problems.

Reference excerpt

The IBM System/360 Model 195 is a discontinued IBM computer introduced on August 20, 1969. The Model 195 was a reimplementation of the IBM System/360 Model 91 design using monolithic integrated circuits. It offers "an internal processing speed about twice as fast as the Model 85, the next most powerful System/360". The Model 195 was discontinued on February 9, 1977, the same date as the System/370 Model 195. About 20 Model 195 systems were produced.

Technical specifications The basic CPU cycle time is 54 nanoseconds (ns). The system has a high degree of parallelism and can process up to seven operations at a time. The system can be configured with 1, 2, or 4 MB of magnetic core memory (models 195J, 195K, and 195L) with a cycle time of 756 ns. A 32 KB cache, called a buffer memory in the IBM announcement, is standard. Memory blocks are brought into cache in units of 64 bytes. The normal operating system for the Model 195 is OS/360 Multiprogramming with a Variable Number of Tasks (MVT).

Components The 360/195 has the following components:

2160 Model l System Console 2180 CPU Power Unit 2185 Power Distribution Unit 2186 Coolant Distribution Unit 2195 Processing Unit (which includes the Processor Storage) 2860 Selector Channel 2870 Multiplexer Channel 2880 Block Multiplexer Channel

Legacy The Model 195 was later updated as the IBM System/370 Model 195 with the new System/370 instructions and the 370 time-of-day clock and control registers, but without the virtual memory hardware.

Notes

References

External links IBM System/360 Model 195 Functional Characteristics

Illustrations

Worked examples

Example 1 — a first encounter with IBM System/360 Model 195

Start with the simplest possible case. Write down what IBM System/360 Model 195 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 System/360 Model 195 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 System/360 Model 195 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 System/360 Model 195

In research: IBM System/360 Model 195 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 System/360 Model 195 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 System/360 Model 195 is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer-related introductions in 1969, Computing platforms, IBM System/360 mainframe line, so understanding it makes those chapters shorter.
In everyday life: Look for IBM System/360 Model 195 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 System/360 Model 195 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what IBM System/360 Model 195 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 System/360 Model 195 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is IBM System/360 Model 195 in simple terms?

Why does IBM System/360 Model 195 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 System/360 Model 195?

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 System/360 Model 195.