Working with MSX BASIC

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Preface MSX is the name for a set of standards to which many computers are being constructed at presen t, and to which many mor e will be constructed in the future. Until the advent of MSX, a tape which had been recorded by one make of machine could not be used on any other machine. Worse sti ll, the programmer of one make of machine would find it q uite difficult t o switch to another machine without rel earning the language. MSX has at long last ended this ridiculous situation, so that anyone who buys an MSX computer will be able to exchange tapes and program ideas with anybody else us ing MSX. The manufacturers may be d ifferent, but the machines work in exactly the same way. An additional bo nus for the retailers is that many of the MSX machines are manufactured by companies who are respected and trusted, with a long history of success in radio, TV and hi-fi. If you have bought this book as a guide to MSX before buying, a few hints on machines may be helpful. Though all of the machines will run the same tapes, and be programmed in the same way, they are not identical. Some, for example, have better keyboards than others. For anyone who does any more with a computer than play games, the provision of a good keyboard is very important. Some machines can be connected to many more devices than others. The business user of a computer will want to connect up a printer and a disk drive, and this is provided for in all MSX machines. If you want to use your computer to control a music synthesiser or to work with pictures from a video camera, however, you may find that some machines are better sui ted to this than others. Very often, you will find that the items to which your MSX computer can be connected reflect the special interests of the manufacturer. To make up a computer system you need the MSX computer, a cassette recorder, and a TV receiver or monitor. All MSX machines provide colour signals to colour TV receivers, and sound signals also. Similarly, all MSX machines can be used with monitors. A monitor is a form of TV which has been designed to take signals directly from a computer or a video recorder, rather than from an aerial. It gives a much clearer picture than you can ever get with a TV receiver. Many manufacturers of MSX computers will probably offer colour monitors in addition to the computers. Most of the MSX manufacturers will also offer cassette recorders, though if you have a recorder already it can probably be used . Many of the MSX manuals say very little about tuning a TV receiver to the computer's signals, or about checking and adjusting cassette recorders, and so these topics have been dealt with in Appendix A. Another important point about MSX is that the system can be expanded; moreover you are not compelled to buy products from just one manufacturer. Many computer manufacturers in the past designed their machines so that it was almost impossible to use additional equipment from any other supplier. This meant that when you decided to scrap the computer, you had to scrap everything else as well. You no longer have to accept this situation, because MSX uses standardised connections and signals. Any computing equipment that you buy for one MSX machine should be usable on any other MSX machine. In addition, if you already have a printer which is fitted with the standard Centronics connection you will be able to use it with your MSX computer; all you will need is a co nnecting cable. If you have used another type of computer, perhaps at school, at work, or at home, then you will readily understand the advantage of the MSX system from reading this book. In particular, you will appreciate the ability to carry out precise arithmetic, and to have easy control over sound and graphics. As your programming knowledge advances, you will find that MSX has even more to offer, particular ly if you are interested in lists and in filing data. For beginner or expert aJike, MSX has a bright future. I would like to emphasise that this book was written while I was using a Toshiba MSX computer, and that the listing of programs in this book were obtained from an Epson printer that was connected to the MSX computer. This might seem to be an unnecessary claim, but many books still appear in which the program listings have been retyped, with errors appearing in many of them. Every program which appears in this book, and every example of programming commands, has been tested on the MSX computer which I have here in front of me. Nothing has been copied untested from the manual, and where a command has operated in a way that is not obvious fr om the manual description I have pointed out the difference. One price that I have had to pay for this has been the d isappearance of the £ signs from several listings, notably in Figs 2.1 8 to 2.20. This is because the pound character which appears on the computer screen does not appear on my prin ter, but I