Contents
Introduction
Chapter 1
 SETTING UP THE ACE
Chapter 2
 SETTING UP THE ACE
Chapter 3
 LOADING PROGRAMS FROM TAPE
Chapter 4
 DEFINING NEW WORDS
Chapter 5
 SIMPLE ARITHMETIC
Chapter 6
 DEFINING NEW ARITHMETIC WORDS
Chapter 7
 ALTERING WORD DEFINITIONS
Chapter 8
 WORDS THAT ARE REALLY NUMBERS
Chapter 9
 MAKING DECISIONS
Chapter 10
 REPEATING
Chapter 11
 SOUND
Chapter 12
 THE CHARACTER SET
Chapter 13
 PLOTTING GRAPHS
Chapter 14
 SAVING PROGRAMS ON TAPE
Chapter 15
 FRACTIONS AND DECIMAL POINTS
Chapter 16
 READING THE KEYBOARD
Chapter 17
 OTHER WAYS OF COUNTING
Chapter 18
 BOOLEAN OPERATIONS
Chapter 19
 MORE ADVANCED ARITHMETIC
Chapter 20
 INSIDE THE DICTIONARY
Chapter 21
 STRINGS AND ARRAYS
Chapter 22
 VOCABULARIES
Chapter 23
 INSIDE COLON DEFINITIONS
Chapter 24
 HOW THE MEMORY IS LAID OUT
Chapter 25
 MACHINE CODE
Chapter 26
 EXTENDING THE ACE
Appendix A
 QUICK GUIDE FOR 'FORTH' ENTHUSIASTS
Appendix B
 ERRORS
Appendix C
 THE JUPITER ACE - FOR REFERENCE
Appendix D
 QUICK GUIDE FOR 'FORTH' ENTHUSIASTS
INDEX

Introduction

In 1950 the National Physical Laboratory made the Pilot ACE (Automatic Computing Engine), one of the earliest British computers. Internally it could store an amount of information measured as 11 Kilobytes, it took 32 microseconds to perform its simplest operation and, with its large number of wires, valves and tubes filled with mercury, occupied a space the size of a small kitchen. Most of its remains can now be seen in the Science Museum at South Kensington.  Based on the Pilot ACE, English Electric developed their DEUCE (Digital Electronic Universal Computing Engine). Over six years they sold about forty of these, costing between 30,000 and £40,000 each.  Now, in 1982, Jupiter Cantab Ltd have produced their own Ace. It can store 3 Kilobytes of information (which can easily be extended) and has an extra 8 Kilobytes of program built into it permanently; the Z80A microprocessor at its heart executes its simplest instruction in just over 1 microsecond, and it is small enough to rest in your lap. Thousands of them will be made, costing less than £100 each.
 How do we at Jupiter Cantab manage it? Not by being extraordinarily clever (although, of course, we are). We are simply the beneficiaries of thirty-two years of development that invented the printed circuit board, the transistor, and then methods of packing thousands of transistors onto one small silicon chip; and in the process transformed computers into machines for everyone.