Microcomputers Interview Preparation Guide
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Microcomputers guideline for job interview preparation. Explore list of Microcomputers frequently asked questions(FAQs) asked in number of Microcomputers interviews. Post your comments as your suggestions, questions and answers on any Microcomputers Interview Question or answer. Ask Microcomputers Question, your question will be answered by our fellow friends.

41 Microcomputers Questions and Answers:

1 :: Explain When was the last Acorn System x shipped?

We designed the BBC machine using System 3s (I did a lot of character design work with a prototype System 80 column video card) and still had System 4/5 stuff going on in 1982 perhaps then.

2 :: What is the Acorn System 1?

Packing them in boxes (upstairs at 4a Market Hill): the whole company would stand around tables (a production square) and put in the right components (me, Hermann, Hermann?s then fianc? Stephen, Chris). We all did pretty much anything: I ended up as Hermann?s secretary before we could afford one!

There used to be problems with answering the phone: one chap would ring up and say ?I have got an Acorn, it does not work? often enough for it to become a legend. We got very tired of kits ? the highlight being a guy who assembled his Atom with glue because he knew that heat (solder) would damage them ? so that coloured the BBC machine a lot.

3 :: Explain When did you build the prototype?

Summer holidays, 1978. Then I went home and drew circuit boards on the dining room table (and floor!) and wrote the manual. All by hand, of course.

Christmas 1978 I must have written System BASIC.

4 :: Explain How did the Acorn Microcomputer get started?

I had designed something similar for myself, and was in the process of helping Hermann [Hauser] with his ideas for an electronic pocket book (what we might nowadays call a PDA). In the course of showing that my designs for it would work, I showed him my schematics for my own machine and was challenged to build it. So I did With my own white ceramic 6502, too. That was just the equivalent of the CPU board of the System 1 with LEDs and keyboard (all on the same bit of Veroboard) the cassette interface was added later. I think Hermann was overly impressed when it worked first time!

5 :: Explain Was the design based on/derived from an earlier machine? Kim-1, Apple I, etc?

Not exactly based on anything. Most of its heritage was from an automated cow feeder that Id designed for a Harrogate company the previous summer (1977). Quite an advanced thing, really it had a (waterproof) number pad, big 7 segment LEDs, OS in non-volatile EEPROM, and the trademark 6502. Both were from my own designs for something for myself, and they came from the aether.

The most hair-raising thing was the cow-feeders programme. I didnt own a PROM blower, so I had to write the whole thing by hand and send it off to a company who hand entered it into a machine and sent me back the PROM. That worked first time, too. Mind you, it was even smaller, being a boot loader that allowed the cow-feeders EEPROM to be initialised.

6 :: Explain Hermann Hauser (from Kings College, Cambridge University) had recently founded Acorn Computers Limited in Cambridge, with Chris Curry, correct?

Actually, that came later. The initial work was done for Hermann?s own company ?Cambridge Processor Unit? (that?s an Austrian?s idea of a joke). Hermann went for the System One and came up somehow with the Acorn name, then Clive and Chris had an argument and Chris left Science of Cambridge and joined Hermann at Acorn: the first thing that we worked on with Chris was the Atom.

At the start, CPU had consultancy contracts for fruit machines. Initially these had been SC/MP based, but they got moved to 6502s. I was first approached by Hermann at a CUPG meeting ? he wanted someone who knew about low power technology, since he had this idea for a ?electronic notebook?. I designed an anti-theft device for the fruit machines (piezo lighters [were] being used to knock out electronic devices, so I put in a wideband radio receiver to stop the fruit machine paying out mistakenly: later on the acceptance test for the machine involved it being plugged into the same power line as an arc welder and sparks being struck ? it passed!). After that Hermann wanted to see my designs that might work for the electronic notebook and asked ?will it work?? ?Of course? ?so build it?.

7 :: What is a microcomputer?

When combined with other integrated circuits that provide storage for data and programs, often on a single semiconductor base to form a chip, the microprocessor becomes the heart of a small computer , or microcomputer.

8 :: Explain Who designed the hardware?

Me for the bottom board. Me, Stephen Furber and maybe Kim Spence-Jones for the top board (cassette interface). (Hmmm ? maybe KSJ was a little later ? he certainly did some of the work on the analogue bits of the BBC machine cassette interface.)

9 :: Explain When did you first show it to Hermann Hauser?

During the time it was built! Hermann was very interested in it. It certainly worked before I went back to Yorkshire before the start of the term.

10 :: Explain Why did you use the RAM I/O chip, instead of a UART or something similar, when the machine had separate RAM?

Because Hermann had them around: Science of Cambridge used 8154s on its MK14 kit (National SC/MP based) and so they were available when we needed something for the 6502. They were fairly cheap and the extra RAM was a bonus, even though it meant converting from 6502 clock/write to the read strobe/write strobe that they used.