We traditionally divide consoles into “generations”—the earliest devices like the Magnavox Odyssey are the first generation, the Atari 2600 is second, the NES third, the SNES and Genesis fourth, the PlayStation fifth, and so on. These divisions turn out to be pretty slippery when you look at them more closely—generations don’t really match product lineage, raw power, or year of release all that closely at all. The closest we come to a real division is that consoles in the same generation competed against one another as peers.
Sega’s third generation may be the most blatant gap there. The SG-1000 came out on the very same day as the Famicom, and it is reckoned as a third-generation console. However, its actual hardware closely matches the ColecoVision, released less than a year before but which is firmly in the second generation. It doesn’t spread terribly far, either. Sega doesn’t make a major play for the international market until 1986, three years after the original SG-1000 release and one year after Nintendo started selling the Famicom internationally as the NES. The NES was a slightly modified Famicom—firmly 1983 tech, albeit very good 1983 tech that had been dominant in Japan for some time by this point. Sega’s offering—the “Master System”—was based on their “Mark III” console from 1985. Those extra two years were pretty busy ones in home computing—1985 in particular sees the release of the Amiga 1000 and the MSX2, both of which offered far more sophisticated graphics than their predecessors. (Indeed, the MSX 1 released the same year as the SG-1000 and had the same graphics chip!) The Master System manages a similar jump as the MSX 1-to-2 advance, or as the Atari 5200 did from the 2600 earlier in the decade.
Also, much like the 5200, the Master System is reckoned as being in the same generation as its own predecessor, though unlike the 5200 the Master System is far more famous and successful than the system it succeeded.
(If you’re looking at the Japanese name of “Mark III” and assuming that the SG-1000 is the Mark I, you may be wondering where the Mark II went. The only real candidate for this is an SG-1000 in different packaging that came out along the way. We’re not missing anything important.)
Head to Head
The Master System was clearly designed to compete directly with the Famicom, but it is also clearly designed to be a broadly-compatible upgrade to the SG-1000. Looking at what the system offers really requires us to compare it both to its predecessor and to its primary competitor. These sorts of comparisons are often a fool’s errand—in this era of home computing particularly, the core capabilities of different machines is so different even in operating principles that the only thing you can do is gesture at how they approached it—but these three systems all have enough in common in their core design that we are on firmer ground. It helps that the Master System’s VDP is explicitly a mostly-compatible upgrade to the SG-1000’s, and that the NES’s PPU is also very clearly inspired by the original principles of that 1979-era chip.
CPU Memory. The SG-1000 matched the ColecoVision, with a single kilobyte of memory visible to the CPU. The Famicom doubled that to 2KB, and the Master System jumped it up to 8. In 1987, an expansion system for the Famicom was releaesd in Japan called the Famicom Disk System or FDS which loaded games off of floppy disks instead of cartridges, and it offered 32KB of additional RAM to actually load games into. This replaced the memory normally mapped to the cartridge ROM but could be used as working RAM by the games themselves.
The SG-1000 matched the ColecoVision, with a single kilobyte of memory visible to the CPU. The Famicom doubled that to 2KB, and the Master System jumped it up to 8. In 1987, an expansion system for the Famicom was releaesd in Japan called the Famicom Disk System or FDS which loaded games off of floppy disks instead of cartridges, and it offered 32KB of additional RAM to actually load games into. This replaced the memory normally mapped to the cartridge ROM but could be used as working RAM by the games themselves. Video Memory. The SG-1000 also matched the ColecoVision here, with a full 16KB of VRAM that enabled full use of all of its graphics modes. The SMS does not meaningfully expand it further; 16KB is enough for its enhanced graphics as well. The only addition on this side is that its palette information is stored in an independent “Color RAM” that only holds 32 bytes. The Famicom only offers 2KB of ordinary video RAM, with 32 bytes of palette RAM elsewhere in the VRAM space, and 256 bytes of “Object Attribute Memory” for sprite data also split out into its own 256-byte bank. 2KB of VRAM is impossibly small; the Famicom’s innovation here is that 8KB of the cartridge ROM is actually mapped directly into the VRAM’s address space as “character ROM” or “CHR-ROM.” Those 8KB are backed by fast RAM in some later cartridges, and the FDS also does this for its disk-based software, ultimately raising the total space available to a hair over 10KB.
The SG-1000 also matched the ColecoVision here, with a full 16KB of VRAM that enabled full use of all of its graphics modes. The SMS does not meaningfully expand it further; 16KB is enough for its enhanced graphics as well. The only addition on this side is that its palette information is stored in an independent “Color RAM” that only holds 32 bytes. The Famicom only offers 2KB of ordinary video RAM, with 32 bytes of palette RAM elsewhere in the VRAM space, and 256 bytes of “Object Attribute Memory” for sprite data also split out into its own 256-byte bank. 2KB of VRAM is impossibly small; the Famicom’s innovation here is that 8KB of the cartridge ROM is actually mapped directly into the VRAM’s address space as “character ROM” or “CHR-ROM.” Those 8KB are backed by fast RAM in some later cartridges, and the FDS also does this for its disk-based software, ultimately raising the total space available to a hair over 10KB. ROM Capacity. The SG-1000 had a hard 32KB limit on the “Sega Cards” that held its games. The Master System expands the ROM space to 48KB and relies on a standardized bankswitching mechanism to allow cartridges to expand up to 512KB. The Famicom relied on more manufacturer-specific bespoke on-cartridge hardware for this capability, with Nintendo requiring standardization to a set of models of their design in the international markets. Famicom bankswitching was generally a bit more sophisticated because its 32KB of CPU ROM space and its 8KB of VROM space needed to be independently controlled. The FDS allowed disks to be swapped so the limit here was more the patience of the end user. By the end of the system’s lifecycle, the largest games for both the NES and Master System were about a megabyte in size.
The SG-1000 had a hard 32KB limit on the “Sega Cards” that held its games. The Master System expands the ROM space to 48KB and relies on a standardized bankswitching mechanism to allow cartridges to expand up to 512KB. The Famicom relied on more manufacturer-specific bespoke on-cartridge hardware for this capability, with Nintendo requiring standardization to a set of models of their design in the international markets. Famicom bankswitching was generally a bit more sophisticated because its 32KB of CPU ROM space and its 8KB of VROM space needed to be independently controlled. The FDS allowed disks to be swapped so the limit here was more the patience of the end user. By the end of the system’s lifecycle, the largest games for both the NES and Master System were about a megabyte in size. Resolution. The SG-1000 and Master System both offer 256×192 displays, while the Famicom expands this to 256×240. In practice, the visible display for all three systems generally ends up more like 248×192 just because analog TVs didn’t render the whole signal visible.
... continue reading