Gary Herman focuses his not inconsiderable attention on the Oric Atmos

The Oric 1 was hailed as a major challenger to the Sinclair Spectrum when it was first unveiled over a year ago. It was, in fact, the first home computer to be reviewed at length in these pages mainly because its virtues were obvious and considerable. Not least of these were a cheap but reasonably pleasant and efficient keyboard and a four-channel programmable sound generator that could use pre-set envelopes and produce a wide range of musical tones at a good volume.

Unfortunately, the machine had its problems. Cassette-based program loading and saving was often troublesome and not very well supported by software. Despite a generally excellent BASIC, there were one or two niggling little omissions. The manual was not very comprehensive though no worse than any other computer's. The keyboard was only superior when compared to the tacky rubber of the Spectrum type. And — worst of all — the company's ups and downs and a general lack of confidence in the machine ensured that it was not adequately supported by hardware add-ons or software (despite which, 160,000 Oric 1's have reportedly been sold to date — one of them to this reviewer).

In fact, all these objections are relatively minor when you consider the Oric 1's price — £10 more than the Spectrum for a vastly superior machine. And now, these objections have been answered by the introduction of the Oric Atmos.

Atmos' here

The Atmos is really a souped-up version of the Oric 1. The bugs have been ironed out (according to Oric), and the cassette routines have been improved and enhanced, whilst the BASIC has been extended to include logical operators (AND, OR and NOT). A new excellent manual has been produced and the Oric 1's calculator-type keyboard has been replaced by a proper typewriter set-up.

The general shape of the machine — including its wedge styled base — and most of the insides remain the same as the Oric 1's. I find the new colours (black and red) a considerable improvement on the blue and off-white of the Oric 1 but I have to reserve judgement on hardware add-ons and software support.

The Atmos is priced at £170 (less than the Electron which I think it beats into a cocked hat) and I can see no reason why its existence should not encourage hardware and software companies to start churning out the goods.

GI Chips

Like its predecessor, the Atmos's music facilities are built round a General Instruments AY-3-8912 programmable sound generator. This chip is similar to the Texas Instruments' 76489 (as used in the BBC computer) but is, in my opinion, just that bit superior. For one thing, it supports a small number of preset amplitude envelopes, unlike the TI chip. For another, it has separate outputs for each audio channel. In the Atmos these are just wired together but it would not be too difficult to break the connection (and your warranty) and run leads to a stand-alone mixer.

I said there were four sound channels on Oric machines. This is not strictly accurate since the noise channel — used for percussive effects and the like — is mixed in the chip with the output of one of the other channels and only three independent tones actually exit the chip. However, that is not much of a restriction.

The Atmos's software includes three powerful sound commands. MUSIC is used to select pre-set notes which are identified numerically, while SOUND gives you access to the full range of frequencies produced by the 8912 chip (some six octaves' worth). Both these commands allow you to select a channel and control volume — MUSIC includes an octave parameter. PLAY is the command which actually produces the sound. It mixes channels (they are, therefore, easy to synchronise) and specifies the duration of the final sound. It also selects a preset envelope if that is indicated in the MUSIC or SOUND commands. You can, of course, create your own envelopes by, for example, playing a rapid sequence of the same frequency at differing volume levels. Use an array in the MUSIC command to specify volume and insert it — and the PLAY command — in a suitable FOR...NEXT or REPEAT...UNTIL loop.

Predictably enough, the Atmos produces all its sounds using unfiltered pulse waves. The only home computer on the market which offers a variety of wave-forms and digital filtering remains the Commodore 64. It is, of course, easier to implement a pulse wave sound generator on a computer than anything else and the use of pulses also means that you don't have to worry about distortion (since your sound is already about as distorted as it can get). However, the resulting tones are invariably marked by a 'mechanical' feel which is acceptable as long as you're happy to make computer music that sounds just like music made by a computer.

Holding It's Own

The Atmos offers an apparent range of timbres and colours that, I think, is not even approached by the BBC Micro. In this respect, it has only two serious competitors — the Commodore 64 and, surprisingly, the Sord M-5 with BASIC-G. For ease of use, the Sord is probably superior, but I think the Atmos — especially with the improvements it contains — holds its own against the Commodore. The music facilities on the latter are inherently superior, but the Atmos is much easier to use. Like the 64, the Atmos has a straightforward audio output so, if you've a soldering iron and a little curiosity, you could be rewarded by using it as a source for sounds to be modified by external digital or analogue circuitry.