Classic Computer Magazine Archive CREATIVE COMPUTING VOL. 10, NO. 12 / DECEMBER 1984 / PAGE 233

Tandy gram. (Radio Shack Color Computer) Jake Commander.

Creative Computing is ten years old--a venerable old age for a microcomputer magazine. No other magazine in this business has been around that long. Creative is the rock of ages of the computer mags. The TRS-80 wasn't even a twinkle in Radio Shack's eye when David Ahl started this thing--a thought that should humble all of us TRS-80 pioneers. This isn't a magazine; it's an institution. As a result, I feel as if I have accepted a position at some long-established hall of learning. So many writers have gone before me; I think to myself in respecful tones, "Who? Me?"

In all seriousness, it is with pleasure and delight that I have accepted the invitation to write a TRS-80 column for this magazine. And bearing in mind that awfully long tradition, I hope I can impart some entertaining, informative, and useful information on the way.

This is a welcome opportunity to share some of the TRS-80 secrets I have managed to unravel during many, many hours of works. For the last seven years, I have been using a TRS-80 in one form or another and can honestly say I have never regretted my original decision to buy one. The product line seems destined to be as long-lived as this magazine. A Bit of History

In days past, however, things were much simpler. When I think back a mere five years ago, I remember that the term TRS-80 meant one thing--the Model I. I could concentrate on writing software for it with the knowledge that my potential audience consisted of a majority of people with Level II Basic installed in their machines. The minority that insisted on using Level I Basic, well, surely they couldn't be serous, and they represented less than 10% anyway. In those days, if you were a Level II expert, you had your TRS-80 doctorate.

In the meantime however, Radio Shack was having other ideas. First the Model II appeared. Apart from sharing the same Z80 microprocessor as its smaller sibligh, the Model II was radically different from the Model I. For a start, the price was nearly eitht times higher, raising the ante to the point were you actually had to save some money if you wanted to buy one.

Radio Shack had also foreseen the business potential of micros and had started courting that fraternity. As far as non-business use went, the Model II didn't change anything. The hackers, beepers, hobbyists, and computer prodigies were still content to poke around inside the Model I, elevating it to heights that must have surprised even Radio Shack.

Then, along came the Color Computer. Apparently, Steve Leininger, the Radio Shack design whiz, has been hard at it again following the success of his Model I design. At first glance, the Color Computer appeared an innocuous little machine that suffered from an incurable 32 characters per line and no lower case. But the harder you looked, the more you could see.

Like a fool, I bought one, opened the case (warranty? what warranty?) and peered inside. Fascinating. It was all so tidy compared with the Model I--no messy external power supplies or expansion interfaces with vulnerable cables dangling out of the back. A screened metal compartment and printed circuit board reduced ratio frequency interference as per FCC regulations. The cassette interface has been redesigned into some semblance of reliability. The keyboard was somewhat inelegant but it had an importan something over its predecessor--no keybounce.

A noticeable feature of the circuit board was preponderance of Motorola integrated circuits. And what was this new chip? A 6809E microprocessor, a long overdue improvement on the Z80. The Color Computer was a very interesting piece of hardware but for a while remained little more than a curiosity as the Model I continued to reign supreme.

Radio Shack can never be accused of standing still. They are a very tight-lipped organization with a more effective control of information leaks than the White House. In Mohammed Ali style, they were about to deliver a one-two. The one had been the Color Computer, and the two was the Model III, a grown up, fully mature Model I--once again, a tidy piece of equipment with nothing more than a power cord for a external cable. While TRS-80-ville was admiring this latest addition to the product line, the Color Computer had begun to defy the critics, and demand had outstripped supply. Fort Worth had started playing hardball, and life in the TRS-80 lane would never be quite the same again.

With the addition of several species of pocket computer, the Model 12, the Model 16, the Model 100, the Model 2000, and various upgrades of the Color Computer, the term TRS-80 is no longer a specific definition. It now refers to whole product line rather than just one or two machines.

Even the microprocessor used in the various machines vary enormously, ranging from the 8085 in the Model 100 to the 80186 in the Model 2000. All this has important implications for a columnist with the task of writing a "TRS-80 column." Future Columns

Ok, so there's the excuse. Now what to do about it. Well, I'm hoping to take up some of the slack left by the departure of The Color Computer Magazine from the scene. So I definitely to cover that machine as a priority. Next on the list, place the Model I/III/4 crowd.

My main workhorse is a trusty old Model III running under LDOS, but I still use my original Model I for many tasks. The sheer volume of Model I software I own precludes me ever ditching the machine. I probably have four times more money invested in Model I software than I do in Model I hardware. Naturally, much of that software will work on the Model III, but you know the name of that game: you can never count on compatibility until you've tried it. Much of the machine code software dosen't transfer across because of direct accesses to the floppy disk controller (which is handled differently on the Models I and III).

Machine code software in both 6809 and Z80 is something I'll try to give some space to. I was professionally dragged up through the ranks of operating systems maintenance on a Honeywell 6000 mainframe, and this has influenced my outlook on computing to this day.

I particularly enjoy nudging my way into the operating system of a microcomputer and convincing it to behave in a different and hopefully more sophisticated manner. I have several pieces of software both in Basic and machine code which have been waiting for a suitable opportunity to be aired. Reviews

Reviews are another possibility dependent upon both the availability of review material and space in the column. For my own personal taste, I find computing per se at least as exciting (if not more so) than staying abreast of the latest developments in the industry.

For the Color computer and Models I/III/4, I'll be glad to pass on any impressions of the latest pieces of software or hardware. To his end, if you are a product developer and would like me to take a look at your latest offering, you can send it to me direct at P.O. Box 495, Peterborough, NH 03458 or via the magazine at 39 East Hanover Ave., Morris Plains, NJ 07950. I can't guarantee inclusion; it all depends on availability of space. Of course, if I see a blockbuster of a product, how could I refuse?

Another source of information is hopefully going to be Fort Worth itself. I make it a point stay in touch with Ed "I know nothing" Juge, Tandy's director of market planning, and he makes it a point to tell me as little as possible in keeping with their policy of not talking about a product until it exists. This is all very laudable but extremely frustrating and usually ends up with me trying to analyze everything he says over the phone to see if he has inadvertently given me a clue to some wonderful new product. I'll try my best. Playing with your Color Computer

It's your column. I aim to please. Let me know what you want to see in it. I am especially interested to know how much review materal you want to see.

Well, after that lengthy introduction, I guess I ought to leave something in my wake other than an empty space, so this small program is included as a tidbit for Color Computer owners. It is the result of some experiments I tried when I first got my Color Computer.

I wanted to put the PLAY command through it paces and see if I could get anywhere close to playing a chord. This is, unfortunately, impossible from Basic on a machine with a single voice, as you need at least three to get a chord. So the idea was to experiment with arpeggios to see if playing them very fast would convince the ear that it was hearing a chord.

Well it doesn't, but in discovering that I ended up with a program that sings like a castrated nightingale that knows no dawn. I also found out something about the PLAY command that is not in the manual.

According to the manual, the Variables contained within the quoted PLAY string (such as octave and volume) must be followed by a numeral. This struck me right away as a little awkward if you wanted to manipulate one of the parameters, say, the volume. To do this as per the instructions in the manual, you would have to change the appropriate numeral within the string. For example, you might have to change V = 10 to V = 9. It would be much simpler if you could just say V = VL where VL is any variable name containing the volume or other parameter desired.

It turns out you can do just that as long as you append a semicolon to the variable names as in V = VL;. This works not only for all the numeric parameters in the PLAY command, but in the DRAW command too.

Here is a line-by-line breakdown:

Line 10 blanks the screen.

Line 20 initializes eight arpeggios.

The whole program is based around the four-chord progression C Am F6 G6. The first four arpeggios are a fast rendering of these, and the second four paly a slower arpeggio.

Line 30 makes a random choice R of the type of arpeggio to be played. If R = 1, then the arpeggio is not one of the four name above but up to five random notes in the key of C.

Line 40 initializes the echo loop.

Line 50 chooses the arpeggio according to the variable R. If R = 1, the arpeggio is already set up. If R = 2, then a slow arpeggio is picked. If R = 3, one of the eight arpeggios is chosen.

Line 55 assigns the chosen arpeggio to the variable X$ (unless already assigned in line 30).

Line 60 scales the octave (one to five) and the volume (1-31) as per the echo-repeat variable, X.

Line 70 plays the arpeggio selected.

Line 80 completes the echo loop, then fades out as four more of the last arpeggios play.

There you have it. It won't balance any checkbooks or fix any of your lost directories. It is strictly for amusement, and I defy you to whistle any of the tunes it invents.