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Supporting imagery<br>Model<br>Motherboard<br>Diagram<br>Model<br>Original<br>Slim<br>The original PlayStation.<br>Released on 03/12/1994 in Japan, 09/09/1995 in North America, 29/09/1995 in Europe.The PS One (slim revision).<br>Released on 07/07/2000 in Japan, 19/09/2000 in North America, 29/09/2000 in Europe.<br>This is what you get after cramming so many custom ICs into a single one.<br>Motherboard<br>Original<br>Marked<br>Motherboard<br>Showing model 'SCPH-1000'.<br>Remaining chips are fitted on the back.<br>Later models included SG-RAM instead of VRAM and removed most of the external I/O and video outs.Motherboard with important parts labelled<br>Diagram<br>Main architecture diagram<br>The Bus Interface Unit is also connected to special ports of the GPU and SPU.

A quick introduction<br>Sony knew that 3D hardware could get very messy to develop for. Thus, their debuting console will keep its design simple and practical… Although this may come at a cost!<br>CPU<br>This section dissects the Sony CXD8530BQ , one of the two big chips this console houses. It’s what we would call a ‘System-on-Chip’ in today’s terms.<br>The origins<br>The main processor follows one of those ‘X designed by Y, based on Z, and second-sourced from W’ arrangements, which is a bit dense to summarise in just a few sentences. So, why don’t we start with some historical context?<br>A bit of history<br>MIPS and Sony<br>LSI and the commission<br>A bit of history<br>A Macintosh Quadra 700 next to a PowerPC upgrade card. Like many adopters of the Motorola 68k, the 90s dictated a necessary shift towards RISC-based CPUs (i.e. PowerPC, in the case of Apple).The early nineties were marked by a turning point in the fortunes of many popular CPUs. The once-leading 8-bit processors, such as the Z80 and 6502, had already faded from the spotlight, and Motorola’s famous 68000, along with other 16-bit designs that enjoyed success in the late 80s, were now candidates for replacement. Even in the PC field at the time, Andrew S. Tanenbaum, in his celebrated debate with Linus Torvalds, predicted that Intel’s x86 architecture had only five more years left until its demise from the home market.<br>At first glance, it may look as though technological development had hit a wall. In reality, however, a new wave of relatively unknown CPUs was beginning to find its way into mainstream devices. Many of these designs originated in academia, and so intended to prove particular sets of design principles. Novel examples from that era include:<br>MIPS : Adopted by Silicon Graphics Incorporated (targeting graphics workstations).<br>PowerPC : Adopted by Apple (targeting desktop publishing).<br>SPARC : Developed by Sun Microsystems (targeting servers and business workstations).<br>ARM : Developed by Acorn, initially targeting the consumer market before expanding into PDAs, cell phones, and other embedded devices.<br>… and many more ‘microcontroller’ chips that had yet to be finalised or adopted by a major industry - such as the Hitachi’s SH and NEC’s V810 . To their surprise, these were subsequently selected for the Sega Saturn and the Nintendo Virtual Boy, respectively.<br>All of these processors had one thing in common: they adhered to the Reduced Instruction Set Computer (RISC) discipline, which radically shifted how such chips were designed and programmed. One rule of the RISC architecture dictated that a single instruction could not mix memory access with register operations. This allowed hardware designers to simplify the circuitry responsible for executing instructions… and then enhance it with parallelism techniques.<br>« Previous<br>Next »

MIPS and Sony<br>The SGI Iris 4D/80, a beefy graphics workstation featuring a twin-tower design. The 4D series inaugurated the MIPS CPU in SGI computers, with this particular model bundling the R2000 processor [1]. I took this photo at the Computer History Museum (Mountain View, California), during my second visit in March 2025.MIPS Computer Systems originated from the eagerness of its founders (Stanford faculty) who were keen to turn their research into physical processors. This aligned well with the appetite of Silicon Valley venture capitalists in the 80s, who were anxious to invest in such innovations [2]. Their debuting CPU, the ‘MIPS R2000’, is considered the first commercial CPU to incorporate a RISC design, and it found a space in many UNIX workstations.<br>However, it wasn’t until 1987 that MIPS’ chips became a topic of conversation, all thanks to their adoption (and eventual acquisition) by Silicon Graphics...