The Introductory Cassette contains lots of interesting demonstration programs which are recorded on both sides of the cassette. If you start at the beginning of side A and follow the directions in this chapter, the computer will take you through each of these programs in turn. When you get to the last program on side A, you will be asked to turn the cassette over and continue on side B.

You will notice that the programs on side B start about a third of the way along the tape. The reason for this is that there are four extra programs at the beginning of side B and at the very end of side A which relate to the book Start Programming with the Electron. When you have got more familiar with your Electron and start using this book, then rewind the tape to the beginning of side B and follow the directions given in the book.

This chapter deals with the demonstration programs only, so insert the cassette into your cassette recorder - side A uppermost.

On some cassette recorders, the volume control setting must be adjusted first before the Electron can 'hear' the programs being played. If this is the case for your machine, set the cassette recorder volume control to about two-thirds maximum, and the tone control (if fitted) to maximum. See if the yellow light on the left of the keyboard is on, and if it isn't press the SHIFT key and the CAPS LK key down together - this will make the yellow light come on. Press BREAK to ensure that the computer is completely reset. Now type the following exactly as it is printed below.

To type each quotation mark, hold your finger on the SHIFT key and press the key with the number 2 on it (immediately above the 2 is the " character). Make sure you type an 'O' and not a zero.

Then press RETURN. If you make a mess of it, don't worry - just press SHIFT and try again.

Press PLAY on the cassette recorder, and the tape should start moving. The message:

Searching

should appear on the screen. This means that the computer is looking for the program called "INTRO" on the cassette. As soon as it has found it, you should see this message displayed on the screen:

This means that the program called INTRO has been found, and the computer is loading it (copying it) into its memory. The program is recorded in 'blocks' on the cassette, and the numbers on the screen next to INTRO tell you which block is being loaded at the moment.

If the message above doesn't appear on the screen after about 30 seconds from pressing PLAY, then turn the volume control up a bit more, and wait for about ten seconds. If there's still no message, turn it up more and keep on until you get a message similar to the one above.

The two numbers to the right of INTRO will be higher than 00 by this time, so completely rewind the tape and start again. Press BREAK and retype:

CHAIN "INTRO"  RETURN

Now that you have found the right setting for the volume control, there is no need to adjust it again.

Once INTRO has been loaded successfully, four numbers appear to the right of the two numbers already there. When this happens, it means that the program has finished loading, so unless the Electron has done it for you already, stop the tape. If you don't, then you'll have to rewind the tape back to the end of the INTRO program before the Electron can load the next program. If for any reason the program did not successfully, a message will appear telling you to rewind the tape and start again.

After a short pause, the INTRO program starts running.

The INTRO program uses some of the colour graphics and sound capabilities of the Electron, and also includes an index of the programs you are about to see on side A of the Introductory Cassette.

Here is a quick guide to the other demonstration programs:

This program will help you to get to know the Electron's keyboard. You will be asked to type different characters from the keyboard. So that you can judge your performance and see how you improve, the computer times you!

Feeling creative? Here's a chance to put your artistic talents to use. In the centre of the screen there is a cross which you can move wherever you like. As the cross moves, it draws a line in the colour of your choice. You can also move the cross without drawing a line - rather like lifting your pen off the paper - and then carry on. The keys you can use and what they do are listed at the bottom of the screen.

The Electron turns itself into a musical instrument. At the bottom of the screen there's a picture of a piano keyboard with the corresponding keys on the Electron keyboard shown. At the top of the screen, the musical score appears as you play.

You are in control of a car driving through a maze of roads which each contain a row of dots. You must drive along every road and clear the dots on them to score the maximum number of points. Unfortunately, there's a computer car coming the other way whose sole purpose in life is to crash into you!

You control the car with five keys which are described at the beginning of the game, and these allow your car to:

• Go left
• Go right
• Go up
• Go down
• Go faster

If you are going too fast, you have to turn at every junction unless you slow down in time. You score one point per dot and one more when they're all gone. Once there are no dots left, a new maze appears and you carry on as before - only this time the computer car travels faster!

This ingenious program plots your 'biorhythms' which is the supposed balance between your emotional, physical and intellectual states. Some people believe that these are regular cycles which show when you are at your best and worst physically, emotionally and intellectually. They also believe that the rhythms started at birth can be predicted mathematically.

All you need to do is enter your date of birth and the date you would like the biorhythm chart for - perhaps today, or maybe you have an important event coming soon, and you want to find out how you'll feel on that day.

The program calculates these cycles from your birth and then displays a chart which indicates your state of well-being on the chosen day. Biorhythms or no biorhythms, this program demonstrates the computer's calculation speed (for example, the number of days from your birth) and how the computer can be used to display graphical information.

This program shows that the computer has more of a memory than you think. Remember the computer asked you the time in the INTRO program? If you typed in the correct time then, you can check it now - either as a digital or analogue read-out. You can even reset it if you want. As well as demonstrating the Electron's high resolution graphics, this program also shows that the computer is an excellent time-keeper.

Gomoku is a very old board game where two opponents (you and the Electron) try to produce a row, column or diagonal with five counters. It is really a sophisticated version of noughts and crosses where you must plan your moves carefully - there is a very large number of possible moves.

The game starts with a blank screen and the message

After you've pressed Y or N, the board appears on the screen, and if you let the computer have first go it will have placed its counter somewhere on the board.

A small cross shows where your counter will be placed. Once you are happy with the position for your counter, press RETURN and a counter appears in place of the cross.

The computer has another go and play continues until one of you manages to get an unbroken line of five counters on the board. The winning line flashes for a few seconds, and if you want another game, press the space bar.

This program tells you to stop the tape (if you haven't got motor control), and continue on side B of the cassette where you will find the programs described below.

This program generates kaleidoscopic patterns in colour, and no two patterns are ever quite the same. To start a new pattern, press the keys marked 1 and 2 in sequence. The pattern itself and its colours are randomly selected each time the keys are pressed and serve to demonstrate the Electron's high resolution colour graphics. If you want to sit back and watch, press one of the keys for a second or two; the computer will continue to generate the patterns until the repeat action of the key you pressed runs out.

You are in command of a spacecraft which you must try to land on a flat section of the Martian terrain as gently as possible. Key X rotates the craft clockwise, and key Y anticlockwise. The space bar fires the rocket motor and makes the spacecraft move in whatever direction it is pointing. To land the spacecraft safely, it must be pointing upwards, at a speed of less than 50 m/s and you must touch down on a flat section of Mars. The score depends on your speed when you land, with a possible 5,000 points for landing at 0 m/s. After a successful landing, the computer will tell you what sort of landing you made, your touch-down speed, how much fuel you have left, and ask you to take off for another landing site which is more than a specified distance away. On each successful landing, you get 30 extra fuel units and your old score is added to your new one.

This program gives you some target practice shooting down a space invader. The keys on the keyboard marked Z and X move the launcher, and the space bar fires missiles at the space invader. Good luck!

This program draws a colour picture of a desert island with palm trees, and a moving sea which occasionally becomes turbulent. This program demonstrates the use of animation in graphics.

This is a very striking example of high resolution colour graphics on the Electron, where animation is used to produce a marked three-dimensional effect.

If you simply follow the instructions on the screen, you will be loading each program into the Electron's memory one after the other. If you want to locate a particular program on the cassette, wind the tape to any point before the program you want (a tape counter can be of great help here) and type

CHAIN "XXXX" (where XXXX represents the program name)

The press the RETURN key. The computer will look through the tape until the program name is found, then it will start loading the program, and afterwards, run it.

Alternatively, position the tape just before the beginning of the program you want, and type

CHAIN ""

Then press the RETURN key. The computer will load and run the next program it finds on the tape. To help you find the beginning of a program, listen to the tape; each program sounds like a screeching noise, and between programs you will hear a continuous high pitched tone. If you start loading during the high-pitched tone then you know you're in the right place.

There are two important points to bear in mind. The first is that the word CHAIN is a command which tells the computer to load the program you specify and then to execute it (run it). So in fact the CHAIN command tells the computer to do two things. The second point is that when the computer is searching for the program you specified, it will still display on the screen the name of whatever program is currently playing. This should give you an idea of how close you are to the program you want. However, remember that whatever program is displayed on the screen, the computer isn't loading it unless you see the word

Loading

above the program name. Don't be fooled into thinking that just because a program name appears on the screen, it is being loaded (copied) into the Electron's memory.

Chapters 9 and 26 give a detailed account of all the facilities made available to you by the Electron when recording (saving) and playing back (loading) programs to and from cassette.