GameStation (console)

The Xaoni GameStation, often referred to as the XGS, is a home video game console developed, manufactured and sold by Xaoni Computer Entertainment. The system was released on the 4th August 1992 in Akarea, while its worldwide roll-out lasted for multiple years, ending with Amurria in 1997. The XGS was the first of the GameStation consoles, which now consists of six systems, two of which are portable, with a seventh slated for release in summer of 2019.

The XGS was an immediate success, becoming the best selling console in most of the countries within which it was sold. While it's high price point became a frequent criticism, it was lauded for its revolutionary Floptical media, which allowed for the use of low-cost floppy diskettes to store games well over 21MB in size, suitable for the immense processing power of the XGS. It remained popular well into the next generation of systems, before pressure from the competition forced Xaoni to introduce an upgraded version called the GameStation SE, which replaced the Floptical technology with standard CD-ROM, and featured more memory and a faster processor. Xaoni stopped manufacture of XGS systems in 2003, although customer support and repairs are still offered.

Technical Specifications
The XGS was notable for being significantly more powerful than its competition. Unlike most consoles of the time, the XGS had a single powerful CPU responsible for logic, video and sound all at once, with the use of software MIDI and a proprietary software renderer optimised for XGS hardware. It was cooled by a single PWM fan mounted to the top of the system, although many electronics experts have questioned the necessity of the fan instead of a large heat-sink.

CPU & Memory
In an unexpected move, Xaoni cooperated with processesor manufacturer IDM to create the GS486 CPU, to be used as the heart of the XGS. Based on the IDM 486XT, a processor designed for desktop workstation computers, the GS486 incorporated extra instructions on top of the standard 486 set for accelerated software rendering and MIDI playback. When interviewed in 1994, the XGS's designer Yuin Qaoying described the decision as "totally, totally necessary." He went on to explain that the XGS was envisioned as a "brute-force powerhouse" from day one, and there were simply "no alternatives" to a cooperative effort with IDM to produce a chip powerful enough to bring their vision for the XGS to life.

The GS486 in the XGS runs at a maximum speed of 58.2Mhz, and during most system operations this speed is maintained. Under some circumstances, such as low CPU utilisation or excess heat production, the clock speed can be reduced to save power and reduce heat production respectively. This behaviour will only occur should the system BIOS detect that doing so would not affect game performance; Since most games use the system's clock speed for timings, performance-incremental CPU speed is rarely used.

The GS486, like the IDM 486XT, has both a 32-bit address bus and a 32-bit memory bus, through which it interfaces with 4096KB of SDRAM. This memory is split across sixteen physical chips, each with 256KB of memory, on a daughterboard which connects to the motherboard with a ribbon cable. Each 256KB cluster was addressable with a single hexidecimal digit, 0 through F, meaning that developers could often split their memory usage, with specific clusters used for specific purposes in the game code. While this is useful from a structural perspective, storing contingent data larger than 256KB is impossible as a result - rather, it would have to be split every 255KB, addressed, and then reconsolidated when needed.

In SUPER SHOCK, the player fights a cyborg
with a pistol. The 256 colour palette can be
seen causing large amounts of dithering in the
darker areas of this screenshot.

Video & Sound
The XGS outputs video at a resolution of 380x240 with an 8-bit colour palette for a total of 256 colours, alongside stereo sound at 22050Hz per channel, generated by both software MIDI and support for low resolution audio sampling from RAM only. These signals would be sent in parallel over a SCART connection to a television set, although an adapter was included with the system to separate the signals for composite cables. In countries where the SCART standard was not recognised, the composite adapter was attached to the back of the unit with four Philips-head screws, although it could still be revealed to show the original SCART socket.

The XGS uses a software renderer stored on the BIOS ROM called HASR, shorthand for Hardware-Accelerated Software Renderer. This software renderer takes advantage of the GS486's instructions for drawing graphics in both 2D and raycasted 3D to provide fast, yet high-fidelity graphics without the use of a dedicated GPU. While many experts and critics were sceptical of the performance a software renderer would offer to game developers and then, in turn, the end consumers, the HASR proved successful, and the XGS was notable for it's high resolution output and consistent refresh rate even when producing complicated polygonal scenes and particle effects, in comparison to its 16-bit competitors.

Similarly, the XGS uses an audio engine, also stored on the BIOS ROM, called MWHAS, shorthand for Midi and Wavetable Hardware-Accelerated Synthesizer. Like the HASR, the MWHAS takes advantage of the GS486's instructions for the acceleration of MIDI audio generation and audio sample playback from memory. Some games took advantage of a small machine code workaround which allowed for sample playback directly from the game diskette itself, although the slow read rate would often prove insufficient for long or higher resolution audio sample playback. The MWHAS featured 128-voice polyphony and support for a live wavetable synthesis, used for the playback of sound samples, although instructions were available for games to use this wavetable synthesis engine as a general purpose synthesizer. Very few games utilised this due to the high CPU usage.

Media
The XGS featured a 3.5" backwards-compatible "Floptical" diskette drive. While the XGS is capable of reading standard 1.44MB floppy diskettes, most games were distributed on 21MB "Floptical" diskettes, manufactured in-house by Xaoni, which use a smaller magnetic read-write head in conjunction with an optical tracking mechansim, allowing for a finer data density over conventional floppy diskette systems which use the magnetic layout for both tracking and data.

The GS486 CPU used in the XGS includes a hardware-level hardware lockout for overwriting "Floptical" diskettes. This means that the game data cannot be tampered with, while the unused space at the end of the diskette can be used for save data storage and, in some cases, as a page file. BIOS modifications have been created which allow this logic to be circumvented, making the XGS extremely popular in console modding and homebrew development communities. Standard magnetic floppy can not be written to at all, even for save data or paging. As a result, standard floppy diskettes were almost exclusively used for shareware demos and arcade ports that did not require data to be kept between sessions.

Xaoni hoped that the immense global success of the XGS would promote the "Floptical" diskette as a viable storage format in the personal computer market. However, attempts to introduce the "Floptical" diskette into the personal computer market were feeble, since the CD-ROM was beginning to emerge at the time, promoting a much greater data capacity and readable speed at a lower cost. The "Floptical" diskette format would soon be abandoned entirely by Xaoni; The successor to the XGS, the Xaoni GameStation SE, used CD-ROMs.