Title: Getting Acquainted with
Your ZX81 (3rd. Ed.)
Author: Tim Hartnell
From: Creative Computing Press
Price: $8.95 paperback
This British book is a good way to move beyond the ZX81 manual if you’re new to computers. Between fascinating graphic display programs (Star Map, Micro Mouse) and challenging games (Space Boy, Alien Imploders) is a reasonable amount of explanatory text.
Hartnell is, from time to time, very good at setting problems for his readers to work out. This is essential in any teaching text, and it is good to find it here.
Significant discussion is given to saving memory by refining programs (with some examples), RND, SCROLL, program-writing suggestions, using arrays and a fair amount more. Finally, after some work programming and numbering a checker board for efficient use in programs is a version of checkers.
The last ten pages may be as much help as all the rest. Hartnell discusses how to change programs from 4K to 8K ROM, gives a set of specifications, a table to convert system variables from old to new ROM, and a listing of the character set, ending with directions for replacing a 4K ROM with an 8K one.
There are minor problems with the book beyond the British names. It is occasionally hard to read programs correctly; at least once I read O for zero and F for E. Using report codes and some detective work, you can figure these out.
Although I haven’t run all of the more than 80 programs, extensive sampling and reading all the text showed this to be a very helpful book for anyone just getting into the ZX81.