Reviewer: Tim Hartnell
Magazine: Your Computer
Date: October 1981
The TRS-80 Colour Computer is Tandy's answer to the Commodore Vic-20. Tim Hartnell runs through its key features including its game-playing ability and its potential for expansion. Prices start at £349 for a basic system with 4K of memory.
The manufacturer of the Tandy Colour Computer has not, in my opinion, made any major design errors, The computer is housed in a standard alpha-numeric keyboard, about the size of the TRS-80, but slightly thicker. The only design problem I found was that a push-button switch at the back, which is an on/off switch, did not appear to turn off the internal transformer, so although the machine appeared to be turned off, the transformer continued to operate.
After a few hours of being “off’, the computer grew very hot, This, coupled with the fact that it was impossible to tell if it was off or on without turning on the television display, meant the push button was, literally, a complete waste of energy - you still have to turn the computer off at the power point.
Apart from this, the computer was a joy to use. The keyboard is full-size, the Basic almost completely standard Microsoft and its only non-standard features were some very useful extra commands and statements.
An oblong cursor, which cycles through the eight available colours, appears when you turn the computer on, If you do not specify a colour-graphic mode, you obtain black letters on a pale-green background. The text on the screen is clear and easy to read. There are no graphical characters obtainable directly from the keyboard - you need to use CHR$n for them.
Although there are eight colours available - green, yellow, blue, red, buff, cyan, magenta and orange - only black on green is available when using text. The command CLS clears the screen to green for text, or if a graphic mode has been previously selected, CLSn clears to the colour specified by n.
If you do not want to use the colour immediately, and you have had some experience using other Basic computers, you will find you can probably use the Tandy Colour Computer from the moment you first turn it on, without even referring to the manual.
The standard Basic supplied on the machine - the review machine had Extended Colour Basic - is such a common subset of Microsoft you should find you can use it without any problems at all - a very big plus for the machine.
The only slightly non-standard feature is the generation of random numbers. To obtain a random number in the range 1 to 10, for example, you enter RND(10) rather than the more usual
INT(RND*10) + 1
Tandy Colour Basic and Extended Colour Basic require the use of the word Then in an If statement, but do not need Let, as in
IF A = 6 THEN LET B = 7
the Let is not needed, whereas the Then is required. The extended Basic will allow the word Let to be in a listing, and will ignore it, while the standard Basic will hang up on the word.
I predict that Tandy will find a ready market among the ex-ZX-80 fraternity, because the standard Basic is almost exactly the same as ZX-80 Basic. Apart, that is, from the character set; Tandy uses ASCII, Sinclair uses its own. The vast majority of ZX-80 programs I tried - except those using screen Peeking and Poking - worked perfectly, when entered without modification on the Tandy.
A simple arithmetic modification allowed even many Peek/Poke programs to run. The address in the first line of a program after the word Rem on the Tandy is 7686, on the ZX-80 it is 16427.
It is in the special features of the Tandy extended Basic that the computer really moves into its own. Here are a few of the unusual commands and functions available:
- This connects or disconnects the cassette output to the TV speaker.
- Draws a circle at a specified location, of specified radius and colour, with a height/ width ratio of your choice - so ellipses can be plotted. All the required information can be entered in a single program line.
- Sets foreground and background colour. Defuser: This command defines the entry point for the USR function.
- This draws a line beginning at a specified starting point, of specified length and colour. As with circle, all the information is entered as a single line.
- A splendid command, it functions somewhat like an Inkey$ command, returning the horizontal or vertical co-ordinates of the left or right joystick.
- Another useful command which fills an area from a specified point with a chosen colour, and stops at a border of a specified colour.
- This triggers the sound output, heard through the TV speaker, and plays music of a specified note, A to G over five octaves. The note duration and volume can be set with the same line. The music played is held in a string. Pos: Returns current cursor position.
- An apparently instantaneous re-number function, used in the direct mode, which also re-numbers Gotos and Gosubs.
- Cycles from zero, or from a number specified, to 65535.
This is a selection of some of the most interesting commands available in the Extended Colour Basic. As you can see, it is highly flexible. You can also program and output in decimal, hexadecimal or octal without any problems. There is also a
PRINT AT (PRINT @)
function, plus Set and Re-set - called ambiguously PSet and Preset, They make dramatic graphic displays relatively easy to achieve.
The only real complaint I have about the Basic is the Edit function. I was unable to understand the instructions in the manual for using Edit - there seem to be about four different procedures which have to be followed, depending on what and where you wish to edit. So I was reduced to re-typing lines whenever I wanted to change them.
I also feel brickbats should be awarded to the supplied software. You can save and load your own programs through the DIN-jack at the back of the computer, but can use commercial software supplied as firmware, plug-in cartridges. The general standard of the supplied software was very low.
The space attack game Quasar Commander and Pinball use PSet and Preset and were apparently written in Basic, so they were slow, jerky and unimpressive. The Football program is incomprehensible without a detailed knowledge of Grid-Iron. Music is a reasonably impressive machine-code program, but entering a melody was slow and laborious, although it played well once entered.
The three most interesting games included Dinowars, which features two dinosaurs moving in three dimensions - that is, towards and away from the players, as well as right to left on the screen. There was a most impressive death howl when one of the beasts was injured.
Backgammon had good graphics and a rapid response, but I could not help feeling the computer was cheating, throwing itself good dice. When I confided this feeling to the distributor of the Tandy, he said he had had the same impression.
Checkers has eight levels of play, an autoplay facility and good graphics. As I have long been interested in computer draughts and have studied many of the game algorithms, I was impressed to be beaten by this Checkers program on level four. My pride would not let me attempt a complete game at level eight.
The colour was bright and vivid from the review computer, although the one supplied was of U.S. origin, running off 110 volts and producing a picture on an American TV. I will be most interested to see if the colours are all well-defined and intense on a U.K. set.
The colours are relatively easy to access from the keyboard, although they are a rather unusual selection. You are never quite sure, as the manual frankly points out, exactly which colour will be produced. Despite this, I managed to produce some splendid, high-resolution designs with short programs.
- Although it is a splendid computer which I found almost impossible to crash, with a good range of standard Basic functions and an imaginative set of additional features, it could well be overshadowed by the Vic, simply because Commodore started to market the Vic aggressively long before it was available here, and may well have better back-up in terms of software, literature and dealer distribution.
- I would think, however, that the Tandy Colour Computer, which has proved very popular in the U.S., should be considered very carefully - especially if you are more interested in writing your own programs than buying commercial software.
- Although the colours are easier to access than are the Vic's, there are fewer of them and they are slightly less predictable.
- There are a number of useful :commands to make using machine code simple on the Tandy, including Cloadm which loads a machine-language program from the cassette; Defuser; Dload which loads a machine-language program at a choice of baud rates, 300 or 1,200; and Exec, which transfers control to machine-language programs at a specified address.
- Also, you can work in decimal, octal or hexadecimal as you choose - or even mix them.
- In short, I feel the Tandy Colour Computer is a flexible and impressive machine which, despite having limited Edit facilities and an unconventional colour system, features a good range of extended Basic commands.
- The close similarity between the Tandy standard Basic and ZX-80 Basic may well make it an attractive next computer for Sinclair users who outgrow their first machine.