Demo Effect - Hardware Considerations

Hardware Considerations

There are demos written for many different devices that vary considerably in their graphical features and data processing capabilities. The variability in hardware also reflects in types of effects invented for each platform as well as in the methods used in the implementation.

The demoscene took off on home computers such as the Commodore 64 and the Amiga, which had relatively advanced and very "hackable" custom chips and CPUs. Before the widespread use of advanced computer aided design for integrated circuits, chips were designed by hand and so often had many undocumented or unintended features. A lack of standardisation also meant that hardware design tended to reflect the designers own ideas and creative flair. For this reason, most "old school" demo effects were based on the creative exploitation of the features of particular hardware. A lot of effort was put into the reverse-engineering of the hardware in order to find undocumented possibilities usable for new effects.

The IBM PC compatibles of the 1990s, however, lacked many of the special features typical for the home computers, instead using standard parts. This was compensated for with a greater general-purpose computing power. The possibility of advanced hardware trickery was also limited by the great variability of PC hardware. For these reasons, the PC democoders of the DOS era preferred to focus on pixel-level software rendering algorithms.

Democoders have often looked for challenge and respect by "porting" effects from one platform to another. For example, during the "golden age" of the Amiga demos, many well-known Amiga effects were remade with Atari ST, Commodore 64 and PC, some of which were considered inferior in the key features required in the effects in question. Since the mid-1990s, when the PC had become a major platform, demos for the Amiga and the C-64 started to feature PC-like "pixel effects" as well.