computer science

STD Bus

STD Bus 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 STD Bus rather than just read about it. In short: The STD Bus is a computer bus that was used primarily for industrial control systems, but has also found applications in computing. The STD Bus has also been designated as STD-80, referring to its relation to the Zilog Z80 series microprocessors.

Key takeaways

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

Reference excerpt

The STD Bus is a computer bus that was used primarily for industrial control systems, but has also found applications in computing. The STD Bus has also been designated as STD-80, referring to its relation to the Zilog Z80 series microprocessors. The term STD is in reference to "standard", but several marketing terms were also promulgated, including simple to design, simple to debug, and swift to deliver.

Description The STD Bus uses 6.5" by 4.5" expansion card with an edge connector with 56 pins. Many different types of cards have been available for the STD Bus, from processing cards, RAM cards, I/O cards, and specialized cards for various applications. The use of the STD bus has declined. From the over one hundred manufacturers of components during its peak, vendor numbers have dwindled to under a dozen, but it is still used by hobbyists, manufacturers and in industrial applications.

Connector pin assignments The STD Bus has a card edge connector with 56 contacts. The pin configuration is as follows. Flow is relative using an STD Bus processor card.

Applications A focus of the STD bus was its ability to build a system using the exact bus cards required for an application. The compact size of a card made the STD bus system more adaptable to various applications than the contemporary computer buses of the mid-1980s such as the S-100 and the SS-50, because it could use servo control cards along with a fully programmable computer for mathematical operations. In applications for running an astronomical observatory, the large industrial base of cards, and the system's expandability, made the system desirable for use in a photometry lab to control the telescope as well as do the data logging and computations required. In typical university laboratory settings of the mid - late 80's, STD bus data acquisition systems were commonplace using Z80 or similar processor cards for the data capture, processing and control, parallel I/O cards for experiment control as well as analogue to digital conversion cards for reading experiment analogue parameters. Such systems would only occupy minimal rack space, while providing full CP/M processing features.

STD-32 The STD-32 is a pin compatible STD interface that allows the co-existence of both 8-bit and 32-bit systems on a single bus. This is accomplished by the addition of pins between the normal pins that do not connect, nor do they interfere with the original specification. This allows with the proper STD-32 backplane the ability to run legacy cards used for specific applications on the same bus without having to upgrade the complete system.

References

Illustrations

Worked examples

Example 1 — a first encounter with STD Bus

Start with the simplest possible case. Write down what STD Bus 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 STD Bus 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 STD Bus 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 STD Bus

In research: STD Bus 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 STD Bus 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: STD Bus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer buses, so understanding it makes those chapters shorter.
In everyday life: Look for STD Bus 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 STD Bus in 20 minutes

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

Frequently asked questions

What is STD Bus in simple terms?

Why does STD Bus 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 STD Bus?

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 STD Bus.