| Fast facts on Sega Dreamcast
| Manufacturer: Sega
| Variants: Sega NAOMI, Atomiswave, Sega Aurora
| Main processor: Hitachi SH-4
|| 499DM €?
|| ?Pts €?
|| ?FF €?
|| 1999-10-14 
|| £199.99 
|| 1999-10-04 
The Sega Dreamcast (ドリームキャスト) is a home video game console manufactured by Sega as a successor to the Sega Saturn. It was originally released in November 1998, becoming first machine to be released in what is now known as the sixth generation of video game consoles, sharing a platform with the PlayStation 2, Nintendo GameCube and the Xbox.
The Dreamcast was Sega's last home console, developed primarily to detoxify the Sega brand and rekindle the trust and market success seen in the days of the Sega Mega Drive. However, faced with significant competition going into 2001, the Dreamcast project was cancelled, with Sega pulling out of the console hardware business it had been persuing for nearly twenty years. Roughly 10.6 million Dreamcast consoles have been sold worldwide.
An arcade counterpart to the Dreamcast exists as the Sega NAOMI.
The Dreamcast is a small, white box with aesthetics designed to appeal to a wide-ranging audience. It was envisioned as an "128-bit" "super console", designed to leapfrog "32-bit" and "64-bit" contemporaries in the form of the PlayStation and Nintendo 64, respectively (although from a technical standpoint, its main processor deals in 32-bit or 64-bit instructions, with the 128-bit figure coming from the graphics hardware). Incidentally the Dreamcast was the last home console to use "bits" as a selling point, with processing capabilities now typically measured in other ways.
Taking design cues from the Nintendo 64 and the Sega Saturn, the Dreamcast contains four control ports, a removable modem, disc drive and an extension port (as well as the expected AV and power inputs). It is not backwards compatible with any prior Sega hardware or software (although its controller derives from the Saturn's 3D Control Pad), and operates in much the same way as the Saturn (and PlayStation) does, with a configurable settings and memory management accessed through a BIOS screen.
The Dreamcast uses a proprietary format of storage called GD-ROMs for games in order to circumvent software piracy, a strategy that ultimately backfired when the first run of discs had a high rate of defects. The format was also cracked fairly quickly (and in some cases, the pirated games were released before the legitimate versions). Sega largely had themselves to blame for the high levels of Dreamcast piracy—their use of the GD-ROM format was completely undermined by the console's support for the Mil-CD format, which allowed the console to boot from a standard CD-R. Mil-CD support was removed from the final Dreamcast revisions toward the end of the console's life.
The GD-ROM format also put the console at a disadvantage when competing against the PlayStation 2 - the PS2 used DVDs, and could therefore run DVD videos making it an inexpensive DVD player as well as a video game console. DVD-ROMs also have more storage space, allowing for bigger games (though the initial run of PS2 games used a blue CD-ROM format). Sega looked into DVD technology during the Dreamcast's development but claimed it was too expensive.
The Dreamcast was the first video game console to ship with a built-in 56k modem, with broadband adapters being made available later on in certain regions. This allowed the system to connect to the internet using a custom, fully-functional web browser and e-mail client. Many games released for the Dreamcast shipped with online play modes, the most popular being Phantasy Star Online and the Sega Sports lineup (now published under the ESPN label). Although other consoles before the Dreamcast had network gaming support, such as the Sega Saturn's NetLink and the Sega Mega Drive's XB∀ND, the Dreamcast was the first game console to include this ability out of the box and is therefore considered the first internet-enabled home game system.
The Dreamcast has a modest hacking enthusiast community. The availability of Windows CE software development kits on the Internet—as well as ports of Linux (LinuxDC) and dreamcast NetBSD operating systems to the Dreamcast—gave programmers a selection of familiar development tools to work with, even though they do not really support the high speed graphics. A homebrew minimal operating system called Kallistios offers support for most hardware, while not offering multi-tasking, which is superfluous for games. Many emulators and other tools (MP3, DivX players, and image viewers) have been ported to or written for the console, taking advantage of the relative ease with which a home user can write a CD which is bootable by an unmodified Dreamcast.
Sega released an arcade board, using the same technology as the Dreamcast, called Sega NAOMI, leading to many Dreamcast-exclusive games with a high level of arcade quality. They later packaged the Dreamcast into an arcade board as the Atomiswave.
- Main article: Dreamcast consoles.
Japanese Dreamcasts can be identified by the triangle at the front of the unit. Though the power LED is identical across all regions, the piece of plastic attached to the lid of the Japanese model is transparent, while in North America it is grey.
For a full list of special edition Dreamcasts, see Special Dreamcast Models.
- Main CPU: Hitachi SH-4 (RISC, 2‑way Superscalar) 
- Operating frequency: 200 MHz
- Units: 128‑bit SIMD vector unit with graphic functions, 64‑bit floating‑point unit, 32‑bit fixed‑point unit
- 128‑bit SIMD @ 200 MHz: Vector unit, geometry processor, graphic functions, DMA controller, interrupt controller 
- 128‑bit graphic computational engine: Calculates geometry and lighting of polygons, creates display lists of polygons for tiling, DMA allows SH4 access to VRAM and PowerVR2 access to Main RAM, store queue mechanism (allowing high‑speed packet transfers between Main RAM and VRAM) 
- Bus width: 128‑bit internal, 64‑bit external
- Bandwidth: 3.2 GB/s internal, 1.6 GB/s external
- Fixed‑point performance: 360 MIPS
- Floating‑point performance: 1.4 GFLOPS (7 MFLOPS per 16 MB/s)
- Geometry performance: More than 10 million polygons/sec, with lighting calculations (140 FLOPS per polygon)
Graphical specifications of the Dreamcast: 
- GPU: 2 core processors (SH‑4 SIMD, PowerVR2)
- Core units: 5 units (SH‑4 SIMD, 4 PowerVR2 cores)
- GPU Geometry Processor: Hitachi SH‑4 SIMD @ 200 MHz
- GPU Rasterizer: NEC‑VideoLogic PowerVR2 CLX2 (PVR2DC/HOLLY) @ 100 MHz
- PowerVR2 Cores: Tile Accelerator (TA), Image Synthesis Processor (ISP), Texture & Shading Processor (TSP), RAMDAC
- TA: Tile renderer, partitions infinite strip polygon data, divides polygons into tiles, performs tile clipping, generates object lists, retrieves display lists from SH4 (through store queues and DMA), generates ISP/TSP parameters
- ISP: Rasterizer, depth‑sorting, RLE tile/polygon compression, parallel‑processing of tiles/polygons at high speeds (1 clock cycle per vector, 32 pixels per clock cycle)
- TSP: Shader and texture‑mapping unit, avoids shading/texturing overdrawn pixels/tiles and back‑facing polygons to maximize bandwidth for on‑screen pixels/tiles and front‑facing polygons
- RAMDAC: 230 MHz 
- PowerVR2 Capabilities:
- Texture mapping: Perspective‑correct mipmapping, environment mapping, 1×1 to 2048×2048 texture sizes, VQ texture compression  (12.52% to 37.5% compression ratios), texture clamping/wrapping/mirroring, multi‑texturing, bump mapping (2‑pass), normal mapping (Dot3 bump mapping)
- Filtering: Point filtering, bilinear filtering, trilinear filtering, anisotropic filtering
- Anti‑aliasing: Super‑sampling anti‑aliasing (up to 4× SSAA), full‑scene anti‑aliasing (FSAA), edge anti‑aliasing
- Alpha blending: 256 levels of transparency, multi‑pass blending, per‑pixel translucency sorting
- Shading: Perspective‑correct ARGB Gouraud shading, flat shading, shadows
- Rendering: ROP (render output unit), 32‑bit floating‑point Z‑buffering (on‑chip), 256 fog effects, vertex fog. per‑pixel table fog, hardware clipping to viewport
- Lighting: Specular highlighting, per‑pixel lighting 
- Tiled rendering: Screen partitioning into 32×32 tiles, tile/strip/line buffer (framebuffer compression), each tile rendered in internal 32×32 buffer in register memory before being copied to main framebuffer, increases fillrate significantly 
- Deferred rendering: Hidden surface removal (32‑bit floating‑point), back‑face culling, culling of tiny polygons
- Polygons: Triangle polygons, quad polygons, sprite polygons, effective performance of more than 10 million polygons/sec (including overdrawn and back‑facing polygons), capable of drawing 7 million front‑facing polygons/sec on screen (geometry data storage for polygon models reduce VRAM available for textures), purely opaque polygons drawn at high speed (32 pixels per clock cycle) 
- GMV (general modifier volumes): Light beams, shadows, lasers, glowing suns 
- Display Resolution: 320×240 to 800×608 pixels, interlaced and progressive scan, TV and VGA
- Internal resolution: 320×240 to 1600×1200 pixels 
- Color Depth: 16‑bit RGB to 32‑bit ARGB, 65,536 colors (16‑bit color) to 16,777,216 colors (24‑bit color) with 8‑bit (256 levels) alpha blending, YUV and RGB color spaces, color key overlay 
- Full framebuffer: 320×240×16‑bit (150 KB) to 1600×1200×32‑bit (7500 KB)
- Strip/Tile buffer: 32×32×16‑bit (4 KB) to 32×1024×32‑bit (256 KB) 
- Geometry Performance: 23 million vertices/sec (60 FLOPS per polygon) 
- Polygon Geometry: Effective performance, including overdrawn and back‑facing polygons not drawn on screen
- 11 million polygons/sec (130 FLOPS per polygon)
- More than 10 million polygons/sec: Lighting (140 FLOPS per polygon) 
- Rendered On‑Screen Polygons: Front‑facing polygons drawn on screen, not including overdrawn and back‑facing polygons (including them, effective performance is more than than 10 million polygons/sec) 
- 7 million polygons/sec: Lighting, textures, shadows, trilinear filtering 
- 6 million polygons/sec: Lighting, textures, trilinear filtering, Gouraud shading (243 FLOPS per polygon)
- 3.3 million polygons/sec: Lighting, textures, trilinear filtering, Gouraud shading, bump mapping (430 FLOPS per polygon) 
- Rendering Fillrate: 
- 3.2 GPixels/s: Opaque polygons (32 pixels per clock cycle)
- 200–500 MPixels/s: Average fillrate 
- 100 MPixels/s: Translucent polygons with maximum hardware sort depth of 60 (1 pixel per clock cycle)
- 100 MPixels/s to 3.2 GPixels/s, depending on opacity/translucency of polygons (1–32 pixels per clock cycle) 
- Texture Fillrate:
- 200–500 MTexels/s: Effective fillrate (including overdrawn and back‑facing textures)
- 100 MTexels/s: Front‑facing textures drawn on screen
- VRAM: 8 MB (unified framebuffer/polygon/texture memory) 
- Framebuffer: 4 KB to 7500 KB
- Polygons: Up to 6511 KB (10 million polygons/sec, 32‑bit precision, 40 bytes per polygon)
- Textures: Up to 8188 KB (63.8 MB with maximum compression)
- Note: Main RAM can also be used to store textures and polygon display lists
- Full Motion Video: MPEG decoding, video compression, 320×240 to 640×320 and 320×480 video resolutions, 3D polygons can be superimposed over FMV video 
- System RAM: 26.125 MB
- Main RAM: 16 MB SDRAM (Hyundai HY57V161610D)
- Can be used for storing textures and polygon display lists, accessible by SH4 and PowerVR2 (via SH4 DMA) 
- VRAM: 8 MB SDRAM (unified framebuffer/polygon/texture memory)
- Accessible by Power VR2 and SH4 (via DMA and store queues)
- Sound RAM: 2 MB SDRAM
- GD-ROM buffer RAM: 128 KB 
- System ROM: 2 MB 
- Flash Memory: 128 KB 
- Internal Processor Memory: 65,232 bytes (63.703 KB) 
- SH4: 26,178 bytes (8 KB instruction cache, 16 KB data cache, 64 bytes store queue cache, 1538 bytes registers)
- PowerVR2: 6274 bytes (128 bytes ISP cache, 1 KB texture cache, 509 bytes fog table, 4093 bytes palette RAM, 256 bytes FIFO buffer, 264 bytes registers)
- AICA: 32,780 bytes (32 KB sound registers, 8 bytes RTC registers, 4 bytes FIFO buffer)
- GD-ROM Drive: 12× maximum speed (when running in Constant Angular Velocity mode) 
- Disc formats: GD‑ROM, CD‑ROM, CD‑DA, , Photo CD, Video CD, CD Extra, CD+G, CD+EG
- Storage capacity: 1 GB per GD‑ROM, 656 MB per CD‑ROM
- System RAM Bandwidth: 1.8 GB/s 
- SH4 <‑> Main RAM — 800 MB/s (64‑bit, 100 MHz)
- PVR2 <‑> VRAM — 800 MB/s (64‑bit, 100 MHz, 7 ns) 
- AICA <‑> Sound RAM — 132 MB/s (16‑bit, 66 MHz)
- SH4 <‑> GD‑ROM buffer — 13.3 MB/s (16‑bit)
- System ROM Bandwidth: 20 MB/s (16‑bit, 10 MHz)
- Internal Processor Memory Bandwidth: 2.7 GB/s
- SH4: 1.6 GB/s (64‑bit, 200 MHz)
- PowerVR2: 800 MB/s (64‑bit, 100 MHz)
- AICA: 256 MB/s (32‑bit, 67 MHz)
- GD‑ROM Drive: 1.8 MB/s transfer rate, 250 milliseconds access time
- Operating Systems:
- Inputs: Four ports that can support a digital and analog controller, steering wheel, joystick, keyboard, mouse, and more
- Dimensions: 189mm x 195mm x 76mm (7 7/16" x 7 11/16" x 3")
- Weight: 1.9kg (4.4lbs)
- Modem: Removable; Original Asia/Japan model had a 33.6 Kbytes/s; models released after 9 September 1999 had a 56 Kbytes/s modem
- Sega Dreamcast Broadband Adapter: these adapters are available separately and replace the removable modem
- HIT-400: "Broadband Adapter", the more common model, this used a RealTek 8139 chip and supported 10/100mbit
- HIT-300: "Lan Adapter", this version used a Fujitsu MB86967 chip and supported only 10mbit
- Storage: "Visual Memory Unit" (VMU) 128 Kb removable storage device
- Input devices: (4 custom controller ports)
- Output devices:
- Main article: History of the Sega Dreamcast.
List of games
- Main article: List of Dreamcast games.
- Main article: Sega Dreamcast/Magazine articles.
Japanese/North American logo
- ↑ File:CVG UK 216.pdf, page 52
- ↑ File:CVG UK 215.pdf, page 59
- ↑ 3.0 3.1 http://web.archive.org/web/20000303160725/http://www.tectoy.com.br/unshock/prop.htm
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Sega Dreamcast: Implementation (IEEE)
- ↑ File:SH-4 Software Manual.pdf
- ↑ File:SH-4 datasheet.pdf
- ↑ 7.00 7.01 7.02 7.03 7.04 7.05 7.06 7.07 7.08 7.09 7.10 File:DreamcastDevBoxSystemArchitecture.pdf
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 File:Dreamcast Hardware Specification Outline.pdf
- ↑ 9.0 9.1 File:PowerVR2DCFeaturesUnderWindowsCE.pdf
- ↑ 10.0 10.1 10.2 http://segatech.com/technical/gpu/index.html
- ↑ Hideki Sato Sega Interview (Edge)
- ↑ Tiling Accelerator Notes
- ↑ Zombie Revenge (21 January 2000)
- ↑ PowerVR (Dreamcast Hardware)
- ↑ Dreamcast Comparison
- ↑ Neon 250 Specs & Features
- ↑ Computer Graphics: Principles and Practice (Page 868)
- ↑ Floating-Point Calculations
- ↑ Vintage Game Consoles: An Inside Look at Apple, Atari, Commodore, Nintendo, and the Greatest Gaming Platforms of All Time (Page 277)
- ↑ File:PowerVR2DCFeaturesUnderWindowsCE.pdf, page 11
- ↑ File:Edge UK 067.pdf, page 11
- ↑ Polygon Calculations
- ↑ Dreamcast & Saturn Specifications
- ↑ File:SH-4 Software Manual.pdf, page 25
- ↑ File:Dreamcast Hardware Specification Outline.pdf, page 6
- ↑ File:DreamcastMagazine UK 03.pdf, page 7