8 - Chess computers are almost human

Abstract

Chess computers are almost human. This chapter describes how a chess computer works, how it is programmed, and how this affects its style of play. There are four basic sections in the brain of the chess computer: (1) the control unit, (2) the arithmetic/logic unit, (3) the memory, and (4) the input-output (i/o) interfaces by which the computer communicates with the outside world. Within the memory section, there are two basic types of memory cell: (1) the ROM and (2) the RAM. ROM stands for read-only-memory, and it is permanent and not dependent upon a continuing power source. The chess program in every dedicated chess computer is stored in ROM, which may be a separate plug-in module or an integral part of the machine; it makes no difference to the computer's central processing unit. RAM means random-access-memory, and it the volatile part of memory in which the current position in the game, instructions to do with the level of play, intermediate steps in calculations etc., are stored under the control of the CPU. If the power is deliberately or accidentally turned off for a moment, or if the reset button on the computer is pressed, then the contents of the RAM are cleared and the computer forgets all about the game that was in progress unless it is one of the battery portables with the memory feature or an expensive model with a CMOS chip, like Champion Mark Six.