You know, building your own computer is easier than you think. At least, it is if you think it's going to be pretty diffucult. Then again, if you think it's going to be easy, then you might find it's more difficult than you think. All in all and not beating around the bush - if you think it's goint to be reasonably easy but with difficult bits, then I'd say you'd got it about right. Anyway, if you want to go through with it - this is what you do...

Ingredients
You will need:-
a. One stout box or case to enclose the works (or 'Hardware' as we computer experts call it).

b. Some 'Hardware'.
Obtain from a Hardware Shop, some transistors, printed circuit, magnetic storage cores, astable multivibrators, binary counters, OR, AND, NOR, NAND gates, flip-flops, oscillators, numerators, comparators, integrators etc, etc. (You realise I'm not talking about any old hardware shop, right? Right.)

c. Also you may need some solder, screws, wire, string, glue and stuff like that, available for a

few pence from your local Computer Outfitters.

Instructions
Well here you are at last - ready to assemble your own Computer. Just follow these instructions and you'll find it all quite simple; always remember the basic rule - think logically! If you do, then you'll find about everything quite as easy as if you were doing everything at all the same in the easy and even logical things can become if you don't care for, so think logically!

Assembling the case
a. Trace the diagram (below, left) on to tracing paper.

b. Trace it again onto another piece of tracing paper - JUST IN CASE! (This is known as a back-up system.)

c. Once you have traced the diagram, carefully re-draw it at full-scale size on a large piece of tracing paper. It should come out at about 8 ft by 15 ft, so you are going to need a piece of paper, say, a bit bigger than 8x15 feet square. That works out at 120 square feet, which is an unrealistic size for a piece of tracing paper really, so you'd

better settle for maybe two 60 sq ft pieces glued together. (Four 30 sq ft pieces would do). Just remember, you need 1114.8364 square decimeters precisely. In other words, you ask for four pieces of tracing paper measuring 1.2162 by 2.286 meters. As a matter of fact, eight pieces

measuring 60.81 centimeters by 1.143 meters would also suffice, as would six pieces of tracing paper, 10.16 cm by 12.7 cm square. (And it doesn't really have to be tracing paper).

d. Apologise to the man in the shop where you tried to buy the

paper. Send him flowers perhaps.

e. Copy the full size drawing on to a sheet of mild steel, 1/4 of an inch thick, and again 120 feet aquare. Or again you can glue together several smaller steel sheets, as in c.

f. Cut out the shape from your steel plate, score the dotted lines with scissors, perforate slots, fold accordingly to the arrows, and insert tabs. Your computer case is now complete.
All you need to do now is to hire a welder to cut a big hole in the back so that you can put things inside it.

Assembly of hardware
a. REMEMBER! In the assembly of the Hardware (or as we Computer experts call it, 'the working parts') we shall be relying on a material as old as the hills, or very nearly. Put it this way, it's probably as old

as some hills, but not as old as most of them. Dot it yet? Well here's a clue: it begins with S and ends with tring. Yes, that's it, string. One of man's earliest inventions, yet still very much with us today, and in the field of computer manufacture, invaluable. Good old string, I say!

b. Well that's quite enough about string.

c. Printed Circuits.

d. Yes, printed circuits. this is a printed circuit.

e. And this is a piece of string. Notice the difference.

f. Let's take another look at the printed circuit.

Rather appealing isn't it? you will note that the elecrtical impulse 'E' enters the circuit at input 'I", and is supposed to emerge at output 'K'. See if you can help E to find his way from I to K without crossing his own tracks - and can you find three hidden ice-lollipops in the picture?

g. Look, when you've quite finished fooling about, let's get on with the job shall we?

h. Trace the pattern of the printed circuit on to a sheet of inert matrix covered with a conducting layer of copper film, then etch the pattern with Hydrofluoric Acid (careful!).

i. That was only a practice. So, when the burns have healed you can proceed to the next step.

j. We live in an age of miniaturisation. Everything is

getting smaller, and there is not much we can about it so there you are. Anyway, your circuit must now be miniaturised, so just copy it once more onto a LSI silicon chip no more than 0.5 mm in width.

k. Never mind the excuses - get on with it!

l. Come off it - you know as well as I do where to get a LSI silicon chip!!

m. No! Not telling!

n. Oh you've got one have you? Right. Titcy, isn't it? Well off you go, get your circuit copied onto it.

o. Well done. And now that you've made your first micr-integrated circuit, it's all just plain sailing. Of course our computer will need more of these tiny circuits - we shall need three or four, maybe

even FIVE thousand of them.

p. Calm down.

q. That's better. Well, now you can settle down to making five thousand of those little circuits. You know it didn't take you all that long to make the first one, and the second one should'nt be quite so difficult...
Tell you what - why not make five thousand little marks, and then you can cross one off every time you finish a circuit, say, one every six months - or even less!

r. After a while, pack it in.

Assembly of hardware: Phase two
a. About five or six years later, you may find the bits and pieces of your unfinished computer, and you may think to yourself...
Did I give up too soon?
Should I have perservered?

Should I have soldered on?
Should I have tried harder to finish what I set out to do?

b. No.

Assembly of hardware: Phase three
a. A few months after phase two, you are ready to commence phase three. Grit your teeth, and take the plunge - it is not time for:

The final assembly
Glue together the remaining parts, nail the integrated circuits in place

(any place will do), tie the whole lot into a neat bunble with string, and voila!

Your computer is complete!
Or at least nearly complete. After all these years you will probably have lost the original case we made (remember?). But don't worry - you can easily find some sort of metal container which will do (see right). Just stuff your computer into it, leave it out on your pavement, and with any luck the dustmen should empty it on Wednesday.