16K Sinclair ZX Spectrum

In 1982 Sinclair introduced the Spectrum, a computer with colour and both upper and lower case letters. The Spectrum was initially available in this 16KB version, an upgrade was then available to 48KB. Because of the different ways in which the ZX81 and the Spectrum use memory, some programs which ran on a ZX81 with a 16K memory pack were too big for a 16K Spectrum.

The Spectrum had rubber keys which gave an odd sensation but were easier to use than the ZX81. It retained the practice of having BASIC keywords entered by a single keypress (sometimes with a combination of SHIFT keys). Some keywords and characters were relocated and there were additional keywords to handle colour. A membrane under the keyboard may eventually wear out and the ribbon-cable connectors are extremely fragile. As a result, today keyboard failure is quite common and difficult to repair.

Oddly for a computer which would come to dominate the games industry, there was no joystick port. A plug-in adaptor would be needed.

At the back of the computer is a connection for the 9v power supply, an edge-connector for a joystick interface, microphone and ear sockets for connecting a cassette recorder and the TV out socket. Sound is provided by an on-board speaker, but one of my 16K models is silent.

There was an introduction cassette called Horizons to get new owners used to their Spectrum.

There was no Sinclair cassette player but music was mostly on tape at the time so there were plenty of models available. Cheaper, less sophisticated models seemed to perform best. The volume needed to be adjusted carefully to avoid load errors.



Sinclair ZX Spectrum Introduction		Sinclair ZX Spectrum BASIC Programming
Stephen Vickers / Sinclair Research		Stephen Vickers / Sinclair Research
(1982).		(1982).
		(Edited by Robin Bradbeer)
The Computer and setting it up
The Keyboard		1 Introduction. 2 Basic programming concepts. 3 Decisions. 4 Looping.
Numbers, letters and the		5 Subroutines. 6 Read, Data, Restore. 7 Expressions. 8 Strings. 9 Functions.
computer as a calculator		10 Mathematical functions. 11 Random numbers. 12 Arrays. 13 Conditions.
Some simple commands		14 The character set. 15 More about PRINT and INPUT. 16 Colours. 17 Graphics.
Simple programming		18 Motion. 19 BEEP. 20 Tape storage. 21 The ZX Printer. 22 Other equipment.
Using the cassette recorder		23 IN and OUT. 24 The memory. 25 The system variables. 26 Using machine code.
Colours		Appendix A - The character set. Appendix B - Reports. Appendix C - A description of
Sound		the ZX Spectrum for reference. Appendix C (part 2) - The BASIC.
What's Inside the Case?		Appendix D - Example programs. Appendix E - Binary and hexadecimal.

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