computer science

Thorn EMI Liberator

Thorn EMI Liberator 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 Thorn EMI Liberator rather than just read about it. In short: The Thorn EMI Liberator was a laptop word processor, produced in the United Kingdom by Thorn EMI Datatech, then in Feltham Middlesex, primarily intended for use by UK Government civil servants. Released in 1985, it is considered to be the first mass-produced British laptop.

Key takeaways

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

Reference excerpt

The Thorn EMI Liberator was a laptop word processor, produced in the United Kingdom by Thorn EMI Datatech, then in Feltham Middlesex, primarily intended for use by UK Government civil servants. Released in 1985, it is considered to be the first mass-produced British laptop. Thorn EMI Datatech simultaneously held the contracts for the repair of the Sinclair ZX80 and ZX81.

History The design of the Liberator was instigated in 1983 by the UK Government's Central Computer and Telecommunications Agency (CCTA). It was envisaged as a portable device to allow civil servants to write and print their own reports, rather than using the services of typists. The CCTA initially contacted Dragon Data to develop the product, but the company went into administration shortly afterwards, and the engineering team were taken on by Thorn EMI to continue the project in 1984. The team consisted of five former Dragon Data employees. Derek Williams headed up the business side of the endeavour, working closely with the CCTA and Thorn EMI senior management. John Peacock managed the finances, vendors, and component suppliers. Jan Wojna designed the hardware and packaging of the electronics into the custom designed case. Duncan Smeed wrote the low level system software and worked closely with Digital Research on the operating system implementation. John Linney created the embedded word processor and terminal emulation applications. The Liberator entered limited production in early 1985 and was officially launched in September of that year, with PR from Aspect Public Relations. The journalist launch was the first promotional event held in the Cabinet War Rooms. Despite plans for improved Liberator Mk1A and Mk2 variants, production of the Liberator ended in September 1986.

Description The Liberator was based on a Zilog Z80A microprocessor and a Gate array implementing the screen controller, keyboard interface and other I/O logic. The LCD had a resolution of 480 x 128 pixels, or 80 columns by 16 lines of text. Interfaces comprised two S5/8 serial ports and two expansion buses, one specifically for extra RAM. Two battery packs were available, a NiCad rechargeable pack giving 12 hours operation, or one holding four AA cells giving 16 hours. The Liberator had 40 kB of internal RAM as standard, plus an optional 24 kB which could be write-protected by means of an external switch and had its own button cell battery to provide non-volatile storage. Another 24 kB of non-volatile RAM could be plugged into the external RAM expansion bus. The Liberator's custom wordprocessing software ran under the CP/M operating system. The external dimensions of the Liberator were 295 x 252 x 35mm.

References

Smith, Tony (12 November 2012). "Liberator: the untold story of the first British laptop (part 1)". The Register. Retrieved 28 January 2013. Smith, Tony (14 November 2012). "Liberator: the untold story of the first British laptop (part 2)". The Register. Retrieved 28 January 2013. Smith, Tony (16 November 2012). "Liberator: the untold story of the first British laptop (part 3)". The Register. Retrieved 28 January 2013.

External links "THORN EMI LIBERATOR, 360 degree model", Russian Vintage Laptop Museum (museum), 6 April 2017

Worked examples

Example 1 — a first encounter with Thorn EMI Liberator

Start with the simplest possible case. Write down what Thorn EMI Liberator 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 Thorn EMI Liberator 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 Thorn EMI Liberator 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 Thorn EMI Liberator

In research: Thorn EMI Liberator 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 Thorn EMI Liberator 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: Thorn EMI Liberator is common in secondary-school and first-year university syllabi. It links to neighbouring topics British inventions, Business laptops, Computer-related introductions in 1985, so understanding it makes those chapters shorter.
In everyday life: Look for Thorn EMI Liberator 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 Thorn EMI Liberator in 20 minutes

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

Frequently asked questions

What is Thorn EMI Liberator in simple terms?

Why does Thorn EMI Liberator 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 Thorn EMI Liberator?

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 Thorn EMI Liberator.