[硬件改造] 硬件设计缺陷 爆料吧

土星的三大设计缺陷


1、Dual CPUs

The Saturn had impressive hardware at the time of its release, but its design, with two CPUs and six other processors, made harnessing this power extremely difficult for developers accustomed to conventional programming. Also, many of the ancillary chips in the system were "off the shelf" components, increasing the complexity of the system because the components were not specifically designed to work together. The hardware also lacked hardware video decompression support, the latter being a major disadvantage during a time when full-motion video was quite popular.

"One very fast central processor would be preferable. I don't think all programmers have the ability to program two CPUs—most can only get about one-and-a-half times the speed you can get from one SH-2. I think that only 1 in 100 programmers are good enough to get this kind of speed [nearly double] out of the Saturn."

—Yu Suzuki reflecting upon Saturn Virtua Fighter development.[8]

The Saturn's dual-CPU architecture was the source of some difficulty for developers. The biggest disadvantage was that both processors shared the same bus and were unable to access the memory registers at the same time. As a result, only one processor could utilize system memory at a time. The 4 KB of cache memory in each CPU was critical to maintaining performance. In general, very careful division of processing, in addition to the already-challenging task of parallelizing the code, was required to get the most out of the Saturn. One example of how the Saturn was utilized was with Virtua Fighter's use of one CPU for each character.[8]
Many of the Saturn's developers, such as Lobotomy Software programmer Ezra Dreisbach, found it difficult to develop for compared to the PlayStation because of its more complex graphics hardware.[9] In order to port Duke Nukem 3D and PowerSlave/Exhumed to the Saturn, Lobotomy Software had to almost entirely rewrite the Build engine to take advantage of the Saturn's unconventional hardware.[9] Also, during testing of an unreleased Quake port for the PlayStation, the Saturn's performance was found to be notably inferior for the game.[9] Arcade conversions like Virtua Fighter were often criticized by the videogame press for its poor, glitchy graphics.
Other developers have contested that the Saturn's shortcomings in these respects are overstated at best. WARP leader Kenji Eno, when asked how WARP managed to produce the impressive 3D visuals of Enemy Zero (a game originally developed for the PlayStation) on the Saturn, replied, "...the PlayStation and the Saturn aren't that different, so moving it[Enemy Zero] to Saturn wasn't too difficult."[10]
Third-party development was initially hindered by the lack of useful software libraries and development tools, requiring developers to write in assembly language to achieve good performance. At least during early Saturn development, programming in assembly could offer a two to fivefold speed increase over C language.[8] To save development costs and time, some programmers would utilize only one CPU, such as with Alien Trilogy.[citation needed] Sega responded to these criticisms by writing new graphics libraries which were claimed to help make development easier.[11] These libraries were presented as a new operating system by Sega of Japan.[11]
Saturn games also improved with time, as with nearly every other console system. One notable example is the Saturn port of Virtua Fighter 2.[11] For instance, later programming techniques employed by Sega's AM2 saw an improvement in performance. Video exists of a canceled version of Shenmue - later released on the Sega Dreamcast - running on a stock Sega Saturn. The video was included in the Dreamcast title Shenmue II.[12][13]


2、Quadrilaterals

Unlike the PlayStation and Nintendo 64 which used triangles as its basic geometric primitive, the Saturn rendered quadrilaterals with forward texture mapping, similar to the 3DO. This proved to be a hindrance because most of the industry's standard design tools were based on triangles, with independent texture UV coordinates specified per vertex. One of the challenges brought forth by quadrilateral-based rendering was problems with textured surfaces containing triangles. In order to make a triangular shaped object, rendering had a fourth side with a length of zero. This technique proved problematic as it caused texture distortion and required careful reworking to achieve the desired appearance - Sega provided tools for remapping textures from UV space into rectangular tiles. These complications can be seen in the Saturn version of Tomb Raider, in which triangular rocks are not rendered as well as other systems' versions of the game.[9]
If used correctly, the quadrilateral rendering of the Saturn had advantages. It could sometimes better approximate perspective than the PlayStation's triangles (linearly interpolated in screenspace),[14] as demonstrated by several cross-platform titles such as Wipeout and Destruction Derby. However, the lack of UV coordinates could produce further problems with clipping textured surfaces - in some games like Sega Rally the UV's would simply be clamped at the near clip plane, although the polygon outlines were clipped correctly. The quadrilateral-focused hardware and a 50% greater amount of video memory also gave the Saturn an advantage for 2D game engines and attracted many developers of role-playing video games, arcade games and traditional 2D fighting games. With creative programming, later games like Burning Rangers were able to achieve true transparency effects on hardware that used simple polygon stipples as a replacement for transparency effects in the past.

3、Cartridge

The cartridge slot gave the potential for adding extra RAM or storage devices for saving games to the system.
Two ROM cartridges were released with Sega Saturn games: one with King of Fighters '95 and the other with Ultraman: Hikari no Kyojin Densetsu. The ROM cartridges contained part of the game data because not enough system RAM was available.
Two different RAM cartridges were released for the system; a 1 MB RAM cart by SNK for King of Fighters '96 and a 4 MB RAM cart by Capcom for X-Men vs. Street Fighter and Marvel Super Heroes vs. Street Fighter. A RAM expansion cartridge was also required for the games Groove on Fight & Final Fight Revenge. Both companies were known for their sprite-based 2D competitive fighting games and many of their subsequent games utilized their respective cartridges (such as Vampire Savior: The Lord of Vampire and Cotton 2: Magical Night Dreams).