Reviewer: David Stobie

Magazine: Your Computer

Date: January 1984

Are the extras worth the extra? David Stobie takes a Peek and a Poke at the 32's big memory brother.

DRAGON DATA has refused to accept the challenge offered by newer arrivals on the market such as the Electron or the Elan and instead of producing a new machine has concentrated on enhancing its old one. A 64K version of the Dragon is now available at a number of high-street stores for £229.

As a long-standing Dragon user, I was excited to find out just how different the new machine was. On opening the box, I discovered that it looked just like the old one. It had the same large and sturdy plastic case, and the same keyboard with real keyswitches. Admittedly it was a smarter grey colour and had the number 64 rather than 32 alongside its rainbow-coloured logo. Closer inspection revealed that it had an extra DIN socket, beside the three for joysticks and the cassette port. This is an RS-232 interface which allows communication between the Dragon 64 and other computers or peripherals, such as serial printers.

I switched on to exactly the same boring green display that I was so used to on the 32. The manual that comes with the machine is identical to that for the 32, but there is an eight-page supplement that tells us all about the extras available on the 64. When switched on, the 64 is actually as 32 and is fully software compatible with the 32. So all cassettes and cartridges work as normal.

To "convert" it to a 64 you need to call up a little bootstrap by typing in EXEC. On doing this, you are greeted by exactly the same turn-on screen but this time the cursor has turned blue. Typing


will tell you that you have 41,241 bytes of user memory available. This is 16,370 bytes more than the 24,871 free on the 32. Of course, with both machines this is extendable by clearing some of the space saved for high-resolution graphics, if you are not using them. Similarly, if you are working in machine code then you do not need the Basic interpreter so the whole 64K becomes available for user programs.

One thing that I have discovered is that some existing machine-code programs do not work in the 64K mode. The space for the extended memory means that the Basic interpreter has to be shifted elsewhere. Where would you guess it has been shifted to? The answer is that it has been placed over the address of the cartridge port, thus making the port unusable. This does not affect games that may be used as normal - you need to turn off the power in order to plug in a cartridge, and when you switch on you are automatically in 32 mode - but it does affect such utilities as a cartridge word processor, or a machine-code monitor or assembler, all of which could make excellent use of the extra space that would be available.

This also denies the use of the cartridge port for other expansions; as a CPU extension bus, it can be used for a variety of peripherals, control and even for a second processor.

Disc drives also use the cartridge port but the operating system is provided by the disc OS and the Bask interpreter is not needed. This leads to one of the chief advantages of the Dragon 64. OS-9 is a powerful 6809 operating system with a great deal of software for business and other "serious" uses. OS-9 needs the memory space available to the 64 and cannot operate on the 32.

As already mentioned, the RS-232 port can be used for communication both with other computers and databases and with serial peripherals; a printer or a plotter. Extra commands are available for using the port; DLoad and DLoadM replace CLoad and CLoadM. Machine-code Pokes are needed to use the RS-232 as a serial printer port and further Pokes may be used to alter the baud rate - the speed at which characters are transmitted. This may need to be altered to match up with the communicating equipment.

The port may also be used with a Modem or acoustic coupler to send or receive data through a telephone line. There is another drawback here though as many databases are transmitted in teletext mode which is not available on the Dragon.

The other new facility available on the 64 is auto-repeat on the keys and, no doubt in answer to criticisms of the 32, a much faster keyboard response. I am no touch-typist but I frequently find on the 32 that if I type "the" or "Run" quickly, I often end up with "te" or "Rn" because the keyboard cannot keep up with me. This is put right in the 64 and may be added to the 32 mode on the 64 machine with, inevitably, another series of Pokes. These do not work on the old 32 machine; I tried.

The infamous USR0 bug has been put right on the new machine. All USR1 USR2 etc., calls now work instead of all defaulting to USR0, In fact, there was a cure for this on the old machine. If you defined user calls as USR01, USR02 etc., they worked correctly. They have also had to juggle with numbers a little so that memory or variable pointer addresses do not become negative numbers if they go above 32768.

The 64 then is a powerful business machine if one wishes to make use of the RS-232 port and/or OS-9 with discs but for the ordinary man in the street there seem to be few advantages and even some disadvantages. The extra memory will appeal to some but do not forget that 32K is already a lot of memory and should be plenty for most home-computer applications. The 64 is really a 32 with the extra facilities stitched on instead of a really new machine. Execs and Peeks and Pokes are needed to use most of the new facilities when they should be an integral part of the machine.

After a year-and-half's experience, I think it is worth having a second look at the Dragon 32. Theoretically it has one of the very best eight-bit processors, the Motorola M6809E which is halfway between an eight- and a 16-bit micro with a large number of instructions.

The Extended Microsoft Colour Basic is a very complete and powerful version with a number of graphics instructions, Paint, Fill, Circle etc., not available on other micros.

The line editor takes some getting used to but works well. The Dragon's greatest disadvantage is the alphanumeric display. Only 16 lines of 32 characters. No lower-case letters, no variation in Ink or Paper, just the same boring black on green - or green on black if you like. The four-colour graphics high-resolution modes seem to choose the ugliest colours possible.

I know that secret colours may be extracted and that text may be added to the high-resolution - 254 by 200 - display by some clever machine-code programming or tedious Pokes, that upper- and lower-case characters may be user-defined on the high-resolution screen but this should not be necessary; they should be there as standard.

However, there are compensations. The keyboard is physically very good with solid typewriter keys and a spacebar. There are no single-key entries as there are on the Sinclair computers, there are no programmable function keys, though this is easy to simulate:


The cassette interface is very reliable and there are few Loading and Saving problems.

Other hidden advantages are that the joysticks ports accept analogue inputs and so may be used for temperature sensors or other transducers. The printer port may also be used to provide digital input/output facilities.

The Dragon is software-orientated so that almost any facility needed can be provided by a program instead of an add-on piece of hardware. For instance Dragon Data with its Compuvoice cassette showed how easy it was to have a speech synthesiser when most other computers need a dedicated chip.

It seems a shame that Dragon Data has not put right the shortcomings of the 32 with its new machine. It might have meant taking a bit of a risk, perhaps abandoning the compatibility with the Dragon 32. But I am sure it would have been a great success.