Aquarius Computer System

[Henoch Holverson]

Aquariusis a home computer designed by Radofin and released by Mattel Electronics in 1983. Based on the Zilog Z80 microprocessor, the system has a rubber chiclet keyboard, 4K of RAM, and a subset of Microsoft BASIC in ROM. It connects to a television set for audiovisual output, and uses a cassette tape recorder for secondary data storage. A limited number of peripherals, such as a 40-column thermal printer, a 4-color printer/plotter, and a 300 baud modem, were released. The Aquarius was discontinued in October 1983, only a few months after it was launched.

Looking to compete in the home computer market, Mattel Electronics turned to Radofin, the Hong Kong based manufacturer of their Intellivision consoles. Radofin had designed two computer systems. Internally they were known as "Checkers" and the more sophisticated "Chess". Mattel contracted for these to become the Aquarius and Aquarius II, respectively.[2]

The Aquarius was often bundled with the Mini-Expander peripheral, which added game pads, an additional cartridge port for memory expansion, and the General Instrument AY-3-8910 sound chip. Other peripherals were the Data recorder, 40 column thermal printer, 4K and 16K RAM carts. Less common first party peripherals include a 300 baud cartridge modem, 32k RAM cart, 4 color plotter, and Quick Disk drive.

Although less expensive than the TI-99/4A and VIC-20, the Aquarius had comparatively weak graphics and limited memory. Internally, Mattel programmers adopted Bob Del Principe's mock slogan, "Aquarius -a system for the seventies".[3] Of the 32 software titles Mattel announced for the unit, only 21 were released, most of which were ports of Intellivision games. Because of the hardware limitations of the Aquarius, the quality of many games suffered. There was such a lack of programmable graphics that Mattel added a special character set (see Character set section), so the games could at least use semigraphics.

Despite its relatively short time on the market, Mattel Electronics and Radofin managed to have most of the announced peripherals available within a month or so of the release of the system. Some products never materialized beyond prototype phase, and some were available only in specific markets. Beginning in 2016, new user-designed peripherals began to show up, mostly on eBay or on vintage computer forums such as AtariAge.

The Aquarius manual did not contain details of any of the ports available. The cassette port, although using the same 5-Pin DIN 41524 connector as the TRS-80, did not have the same pin out and thus was incompatible with readily available cables for the TRS-80, even though they physically fit the sockets on both the computer and cassette player. The Aquarius branded cassette deck came with the appropriate cable.[8]

The printer interface is a mini-stereo socket with 3 lines, the same as on the Mattel Entertainment Computer System. The Aquarius printers came with their own cables. The interface conforms to RS-232 serial signal standards (+12VDC/-12VDC), with the knowledge of the pinout it is possible to interface printers with a corresponding RS-232 interface.[8] The serial is fixed to 1200 baud 8N2 and provided both carriage return and line feed commands to the printer, thus the printer needed to be set to not auto feed with carriage return.[8]

Typical serial printers had DB-25 interfaces; some had DE-9 interfaces; and, some Radio Shack (RS) printers had round 4-pin female DIN connector serial interfaces (with the pin sockets numbered left-to-right: 4, 3, 2, 1). The proper cable for connecting such a printer is as follows:[8]

HISTORY OF HOME AND GAME COMPUTERS

The BeginningAtari's PongMagnavox Odyssey Home ComputersCommodore SX-64MattelAquariusPhilips P2000RobotronZ1013Sinclair ZX80Sinclair ZX81SinclairZX SpectrumSinclairZX Spectrum PlusSinclairZX Spectrum 128TexasInstruments 99/4TexasInstruments 99/4a Game ConsolesAtari's Home PongMattelIntellivisionPhilipsVideopac G7000Vectrex Navigator

Many prototypes

As a consequence of the bizarre history of the Aquarius computers, many extensions which were announced hardly appeared on the shelves or never became more than a prototype. An example is the Master Expansion Module. According to employees, only the cases of the module were ever manufactured. The Master Expansion Module should have contained two floppy drives and should facilitate the use of CP/M.

Causes of failure

The main cause for the failure of the Mattel Aquarius is most probably that it halted between two opinions. The developers had hoped to make a combination between a game console and a home computer, but in both respects it performed terribly. Hold your breath: which follows is a long list of mistakes. Expensive extensions

Indeed, the Aquarius had 4K of RAM at its disposal, but in fact the consumercould only use 1,7 K. Needless to say that this amount of RAM was fairlyuseless. In this way, working with the word processor Fileform which Mattel soldon a cartridge, was almost impossible. Unless the user was prepared to storeparagraphs again and again on tape or print them on paper.

In an attempt to compensate this, Mattel Electronics sold various comparativelyexpensive extension options. Examples are the 4K and 16 K RAM memory expansions;cartridges which could be plugged into the Aquarius. Besides that, there was theso-called Mini Expander that could be attached to the computer. With the MiniExpander - almost taller then the tender Aquarius itself - you could use twocartridges at the same time (e.g. RAM-extension and a game). It gave theAquarius also two extra sound channels and two Intellivision-like controllers forplaying games.

Besides that, the Mini Expander was equipped with the same sound chip (AY-3-8914) as the Intellivision. But that didn't appeal to the programmers: they almost considered it as a punishment to develop a game for the Aquarius. Programmer Bob Del Principe even invented this cynical slogan: 'Aquarius - system for the seventies!'

A while back, I started a thread which was intended to be a place where interested programmers could go to find everything they needed to get started with assembly language programming on the Aquarius. Since then, with the popularity of batari Basic for the Atari 2600 and other homebrew-oriented languages, there has been some interest in developing games for the Aquarius in BASIC, so ... here's another Aquarius thread, just for BASIC programmers!

Fortunately, the Aquarius already has its own version of BASIC, and it's built right in to the computer! When you turn on your Aquarius (without a cartridge inserted), or start your favorite Aquarius emulator, you'll be presented with a startup screen for Microsoft BASIC. This is the BASIC interpreter that is built in to the Aquarius OS ROM, and contrary to what you might have read elsewhere, it is a perfectly capable implementation of BASIC; it is not a "crippled" version that is missing such elementary features as the ability to do FOR-NEXT loops. The Extended BASIC cartridge (released in very limited quantities, and available today as part of the Aquaricart) did add a few "missing" features, such as the ability to edit previously entered lines of code, but you can easily live without most of them, and as we'll see, there are even better ways of editing BASIC programs using the tools available today.

This distribution archive includes the emulator itself, the OS ROM, several cartridge and cassette images, and a few sample BASIC programs in ASCII text format to get you started (more on these later). This is the primary emulator that I will be writing my instructions for in this thread, since it has a few features which are especially useful for BASIC programming but which other Aquarius emulators (such as MESS) presently lack.

(There is no "installer" for this emulator; just unpack the ZIP archive into a folder, move the folder to a convenient place, and open the "aquarius.exe" executable inside the folder to start the emulator. It's a few years old now, but I've used Virtual Aquarius under every version of Windows from XP through Windows 8 (in Desktop mode), and it appeared to function perfectly.)

Next is a bootloader utility, generously provided by Martin v.d. Steenoven, which will convert completed BASIC programs of up to 16K into cartridge images. You can use these images in Virtual Aquarius like any other cartridge binary, or even burn them to a 16K cartridge ROM for use with a real Aquarius. In either case, your BASIC program will load and start automatically when the Aquarius is started; the users will not even see BASIC. Here is a link to the most recent version of the bootloader from the assembly thread, along with Martin's usage instructions:

(Note that it is not necessary to use this bootloader utility until after you have completed your BASIC program. While you are writing your program, you would load it into BASIC for testing, using the procedure I will outline in my next post. If you are interested in putting your first completed program onto a real cartridge, send me a PM; I'll be offering a cartridge publishing service in the near future.)

For a long time, this character set posed a problem for emulation authors: the contents of the original ROM are not directly accessible, so most emulators (including Virtual Aquarius) have used "approximations" of the original Aquarius characters. For complete character sets that were drawn by hand, they were remarkably close, but several of them included subtle but noticeable discrepancies.

You can use the replacement ROM with the Virtual Aquarius emulator, but the current version has a bug: it provides a "Browse" button to choose a different character set, but this button doesn't seem to do anything. Here is a workaround:

Once you have unzipped the Virtual Aquarius archive into its own folder, look for a subfolder inside it called "ROM". This contains several cartridge dumps, as well as a dump of the Aquarius operating system. Copy this character ROM into this folder and rename it to "CHARS.BIN". Then, open Virtual Aquarius, open the "Configure" menu, select "Memory ...", and toward the bottom of the dialog box, select the "Load 2K Character ROM from disk" radio button and click the "Browse" button. Click OK to reset the emulator.

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