computer science

NCOS

NCOS 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 NCOS rather than just read about it. In short: NCOS is the graphical user interface-based operating system developed for use in Oracle Corporation's Network Computers, which are discontinued. It was adapted by Acorn Computers from its own RISC OS, which was originally developed for their range of Archimedes desktop computers.

Key takeaways

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

Reference excerpt

NCOS is the graphical user interface-based operating system developed for use in Oracle Corporation's Network Computers, which are discontinued. It was adapted by Acorn Computers from its own RISC OS, which was originally developed for their range of Archimedes desktop computers. It shares with RISC OS the same 4 MB ROM size and suitability for use with TV displays. In 1999, Pace acquired the set-top box (STB) division of Acorn Computers, this being a component in the disposal of assets around the takeover of Acorn by MSDW Investment Holdings. This gave Pace the rights to use and develop NCOS. RISCOS Ltd later announced Embedded RISC OS, which was to have similarities with NCOS.

Development NCOS originated in connection with the Network Computer project. It was used on various STB products. It branched from RISC OS 3.60 and was called RISC OS 3.61 before being named after Network Computer Operating System. It was merged back into the HEAD whilst at Pace, where it was known as RISC OS-NC and RO-STB.

Features NCOS was designed in accord with the Network Computer Reference Profile and thus supports internet standards of the time. Being closely based on RISC OS, it can also run many of that operating system's applications. Reporting on the launch of the Network Computer in 1996, it was noted that NCOS was essentially the same as RISC OS but with some features removed, such as "support for local file systems", whereas other features such as network support had been added to ROM. The actual differences involved the absence of "modules significant to the operation and networking" of existing RISC OS versions, including the Filer, TaskManager and Pinboard modules, plus a range of networking modules. The use of files stored on a server and accessed using the Network File System (NFS) also imposed restrictions on the files used by applications, with recommended techniques for the deployment of applications involving the transfer of files over NFS from RISC OS clients or the use of archives in the largely Acorn-specific Spark format, with these being unpacked on the server using an appropriate tool.

See also Network operating system RISC OS character set

References

Worked examples

Example 1 — a first encounter with NCOS

Start with the simplest possible case. Write down what NCOS 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 NCOS 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 NCOS 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 NCOS

In research: NCOS 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 NCOS 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: NCOS is common in secondary-school and first-year university syllabi. It links to neighbouring topics ARM operating systems, Acorn Computers operating systems, Operating system stubs, so understanding it makes those chapters shorter.
In everyday life: Look for NCOS 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 NCOS in 20 minutes

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

Frequently asked questions

What is NCOS in simple terms?

Why does NCOS 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 NCOS?

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 NCOS.