The Saturn was built from eight processors. Two Hitachi SH-2s shared the main work, one video chip drew sprites and polygons while a second built the backgrounds and combined the picture, a Motorola 68EC000 ran the sound, and a separate SH-1 ran the CD drive. Sega’s own hardware manual for it runs to six volumes. In Japan the machine sold out on its first day and went on to do well. In America, Sega launched it four months early as a surprise, and the PlayStation took the market anyway.
Fast facts
- Manufacturer: Sega.
- Launched: Japan, 22 November 1994 (¥44,800); North America, May 1995 ($399); Europe, 8 July 1995 (£399 with Virtua Fighter).
- CPUs: two Hitachi SH-2s at 28.6 MHz, each with a 4 KB cache, sharing one bus.
- Video: VDP1 draws sprites and polygons into a frame buffer; VDP2 scrolls and rotates up to five background screens and combines them with VDP1’s output.
- Sound: SCSP (Saturn Custom Sound Processor), made by Yamaha, with 32 PCM/FM slots and its own DSP, driven by a Motorola 68EC000 at 11.3 MHz.
- Memory: 2 MB main RAM; 512 KB VDP1 VRAM plus two 256 KB frame buffers; 512 KB VDP2 VRAM; 512 KB sound RAM; a 512 KB CD buffer.
- Media: double-speed CD-ROM (300 KB a second), controlled by its own SH-1; a cartridge slot.
Eight processors
Sega’s 1997 overview manual lists the parts. The main system has two SH-2 RISC processors at 28.6 MHz, 32-bit inside and out, each with a hardware multiplier and divider and a 4 KB cache. The clock depends on the screen mode: 28.6364 MHz in the 352-pixel mode on an NTSC machine, 26.8741 MHz in the 320-pixel mode. The System Control Unit (SCU) connects the processors’ buses and has its own DMA controller and a DSP running at 14.3 MHz, which programmers could use for geometry calculations. The sound block has its own processor, a 68EC000 at 11.3 MHz, and the CD-ROM system has another, an SH-1 at 20 MHz, so the main CPUs only have to send it commands.
Count the two SH-2s, VDP1, VDP2, the SCU’s DSP, the sound DSP, the 68EC000 and the SH-1, and you have eight. Getting them to work together was the job. The SH-2s shared one bus to main memory, so when both wanted it, one waited. Fabien Sanglard, who studied Sega’s manuals for his Game Engine Black Book: DOOM, notes that the programmer had to protect shared variables with mutexes and semaphores, which were “uncommon concepts for game console programmers”. A 1995 development journal by Mick West, quoted in the same book, shows where many teams started:
Currently we only use the Master SH2, the slave SH2 will be used when we get around to figuring out how.
Two video chips
The Saturn’s graphics are split between two chips with very different jobs. VDP1 draws. It reads a list of commands and draws “parts” into a frame buffer one pixel at a time: sprites (textured shapes), polygons, polylines and lines. Sega’s VDP1 manual defines polygons as “filled squares”. The machine has no triangle primitive, so a 3D model is built from four-sided shapes. The “distorted sprite”, a texture stretched between four freely placed corners, is how the Saturn draws a textured 3D surface. VDP1 fills the shape with lines, and Sega’s manual is candid about the cost: to stop gaps appearing, “holes are filled”, so “there may be some pixels that are written twice”, and the result of half-transparency on a distorted sprite “cannot be guaranteed”.
VDP2 does not draw anything. It scrolls and rotates up to five background screens, decides which layer is in front, and mixes VDP1’s frame buffer into the result with colour calculations such as transparency. While VDP1 draws the next frame into one buffer, VDP2 shows the previous one from the other.
That split suited 2D games, with several scrolling layers behind large sprites. It made 3D harder. A game built for triangles had to be reworked around quadrilaterals. Textures were mapped forwards across the shape, which Sanglard notes is efficient for sprites but not when a 3D texture is magnified or shrunk. And the programmer had to sort the scene: “Priority has no effect between parts,” Sega’s introduction for developers explains; “to place parts in front of other parts, you must draw them in sequence, backmost part first.” Sanglard’s summary is that the Saturn’s quads “could be distorted in screen space to poorly fake perspective. It was not a matter of not trying hard, the hardware was complex.”
A sell-out in Japan
Edge was in Akihabara on 22 November 1994, ticket number 306 in a queue of about 600 outside the Laox Computer Game Centre. It waited two and a half hours. “200,000 units sold out instantly on day one,” it reported, and a Sega source said the company had held back 300,000 more for when Sony’s PlayStation arrived. The price was ¥44,800 (£290), “with Virtua Fighter the only worthwhile game available”. Edge called it “a near-perfect conversion of the Virtua Fighter coin-op”.
Japan remained the Saturn’s strongest market. In May 1996 Edge reported the Nikkei newspaper’s estimate that Sega’s share of the Japanese market had risen from 12 per cent in 1994 to 32 per cent in 1995, while Nintendo’s had fallen from 75 per cent to 33. Hideaki Sasaki of Sega Multimedia told Edge that Sega had “shipped over 3.7 million Saturns by October ’96”. Sega also sold a Saturn modem in Japan, at ¥14,800, with a web browser and access to the X-Band network for online play; Sasaki said 30,000 had shipped by the end of October 1996.
The surprise American launch
Sega had announced “Saturnday”, 2 September 1995, as the American launch. On the morning of Thursday 11 May, at the Electronic Entertainment Expo (E3) in Los Angeles, Sega of America’s president Tom Kalinske told the audience that the date had been a decoy. “We started our roll-out yesterday; we’re at 1800 stores around the US and Canada today,” Edge quoted him. Sony learned of the move a few hours before its own PlayStation presentation. The PlayStation was due in September, at $299.
The Saturn cost $399 on its own, or $449 with Virtua Fighter. Edge found that stores were buying the machines from Sega at $399 and making their money on the five games available at launch.
Europe followed on 8 July 1995, two months earlier than planned, at £399 with Virtua Fighter. More than 5,000 were sold in Britain in the first week. Supply was short: the distributor Centregold received 50 of the 500 machines it ordered.
Losing to the PlayStation
The PlayStation cost $100 less in America, and Sanglard notes that Sega’s 3D games suffered beside Sony’s Ridge Racer, with a lower frame rate and polygons popping into view. By July 1997 Sega had cut the American price of the Saturn to $149, and admitted that it expected to ship 1.9 million Saturns worldwide that year, “half as many as in ’96”, and would concentrate on software rather than “unprofitable hardware”. Comments at E3 in 1997 that “the Saturn is not our future”, which Wikipedia attributes to Sega of America’s Bernie Stolar, reached Edge’s letters page that September from a reader who felt Sega had “let down its console owners yet again”.
Sega was already working on the Saturn’s successor. It had commissioned a graphics chipset from the American company 3Dfx, and cancelled the contract in July 1997; the machine that followed was the Dreamcast.
Wikipedia’s figures, a secondary source, put total sales at 9.26 million: 5.75 million in Japan, 1.8 million in the United States, 1 million in Europe and 530,000 elsewhere. By the same account Sega stopped selling it in North America and Europe in 1998 and in Japan in 2000.
The games
The Saturn’s library is strongest where its hardware was: Sega’s arcade conversions and Japanese 2D games. Sega brought over its own coin-ops, from Virtua Fighter and Daytona USA to Virtua Cop and Sega Rally. Sonic Team made NiGHTS into Dreams, which came with an analogue controller, and Treasure made Guardian Heroes, a side-scrolling 2D beat ’em up whose “enormous sprites take full advantage of Saturn’s hardware abilities”, in Edge’s words, with up to twelve enemies on screen at once. The Panzer Dragoon series ran to a role-playing game, Panzer Dragoon Saga. Capcom’s fighting games pushed the memory: its Marvel Super Heroes was sold in Japan packaged with a RAM cartridge for the expansion slot, and Edge found the two together gave “a stunning, near arcade-perfect experience” with shorter loading and more frames of animation.
Sources
- Sega, Sega Saturn Hardware Manual (1997): Overview Manual, chapters 1–3 (processors, clocks by screen mode, cache, memory sizes, the SCU DSP, the SH-1 and the double-speed CD-ROM at 300 KB a second); SCSP User’s Manual, section 2 (32 slots, FM and PCM, the 128-step DSP, the 68EC000 at 11.2896 MHz).
- Sega, VDP1 User’s Manual: parts, “polygons are filled squares”, the distorted sprite, drawing order and the half-transparency limitation.
- Sega of America, Introduction to Saturn Game Development, preliminary draft, July 1995: VDP2’s background screens, priority and colour calculation; “Priority has no effect between parts”.
- Fabien Sanglard, Game Engine Black Book: DOOM (2018), section 6.6, pp. 352–356: Mick West’s 1995 development journal; the shared bus and the concurrency problem; VDP1’s forward texture mapping; Daytona USA beside Ridge Racer; the SCSP identified as Yamaha’s YMF292.
- Edge issue 17, February 1995: the Japanese launch, sales and price.
- Edge issue 32, May 1996: the Nikkei market-share estimates.
- Edge issue 41, January 1997: Hideaki Sasaki on the Saturn modem, X-Band and 3.7 million Saturns shipped.
- Edge issue 23, August 1995: Kalinske’s E3 announcement, the $399 and $449 prices, retailer margins; the UK launch date and price.
- Edge issue 24, September 1995: the European launch, first-week UK sales and the Centregold shortage.
- Edge issue 47, July 1997: the $149 price, the 1.9 million forecast and Sega’s shift to software.
- Edge issue 31, April 1996: review of Treasure’s Guardian Heroes.
- Edge issue 33, June 1996: Sonic Team’s NiGHTS.
- Retro Gamer issue 5, 2004, “Sega Ages”: NiGHTS and the analogue pad.
- Edge issue 50, October 1997: Marvel Super Heroes and the Saturn RAM cartridge.
- Edge issue 49, September 1997: the reader’s letter on “the Saturn is not our future”; the cancelled 3Dfx contract.
- Wikipedia, “Sega Saturn” (web, secondary): lifetime and regional sales; the dates Sega stopped selling the Saturn; Stolar’s E3 1997 remark. https://en.wikipedia.org/wiki/Sega_Saturn