This ROM offers around 40 extra commands and utilities, all of which are RSX's (Resident Systems Extensions) and so need a bar ("|") prefix, e.g. |FRAME.
The commands are arranged in four different categories of which the first is the actual writing and debugging commands to help you to find errors in your own programs. Particularly useful among these is the find/replace command, which will search through listings in much the same way as a word processor will go through a document finding one word and replacing it with another. Other useful commands include one to trace the program currently running to the printer.
The second group of commands comprises those missing from 464 BASIC but which are present in BASIC V1.1. A program written on a 664 or 6128 (so long as it does not use too much memory) is fairly easy to translate to the 464 with these commands. However, since a program written with these RSX's will not work on a 664 or a 6128 until all the bar ("|") prefixes have been removed they are not quite the complete answer to the compatibility problem.
The ROM also contains some commands which do not exist in any form of Locomotive BASIC. These include two dump routines which take the graphics screen and dump it to either an Amstrad or an Epson printer. (An extra command, |PRINTER, selects the printer type). The problem with these commands is that if you write a program containing them, nobody else can use that program because their machines will not be able to handle the extra commands.
The last group of commands features design programs. These include a character generator and an envelope tester, and are very useful as they produce BASIC Program lines when you have finished designing. You can then put those BASIC lines in your own program, and they will recreate the sound. Much better than trial and error to find the right sound or character shape.
All the routines are well designed. The screen layouts are very good and fairly easy to grasp. If you feel at ease with most of Locomotive BASIC then you can master these with a little effort.
P. Wide range of extra commands; it's likely you will find something that will help you.
P. The manual is well written, explaining things very clearly.
N. No facility to save commands, so other people cannot use your programs unless they also have a copy of this ROM.