Price: £4.95 (about
$10)
ROM/RAM reqd: 4K/1-16K
Printed listings? Yes
Programs listable? Yes
Screen prompts? Yes
Easy to load? Yes
Display: Excellent
From: JRS Software, 19, Wayside
Ave., Worthing, England, BN13 3JU
At last you can know the secret of true flicker-free continuous display through software! If you’re a 4K ROM user envying the ZX81’s continuous display, envy no more. For about $10 you can code a rock-steady, moving display into your 4K ZX80.
You get an 8-page instruction booklet, a cassette tape with sample programs, blank and demo coding sheets, and graph paper. The booklet contains directions for running the demo programs, writing your own moving display routines, and gives directions for RAMs over 1K. A complete, step-by-step example accompanies the detailed instructions. With no independent thought, I ran through their example and it worked perfectly.
The cassette holds only one copy of each program, so you should immediately make backup copies on your own recorder. The programs are recorded with a voice leader and load easily.
This routine works very well, but be forewarned that it is not a couple lines of BASIC that you plug into your own programs. Planning the display requires forethought and careful plotting on the supplied graph paper. Then you must type in numbers corresponding to calculated locations and character codes. But JRS‘s input program and written directions make this task as simple as possible.
The quality of both the display and the documentation impressed me.