Kutaragi talks more on PlayStation 3
Sony Computer pres says defective PS3 Cell chips may end up in home servers; back Blu-ray (again) as the only choice.
In the latest issue of Nikkei Electronics, Sony Computer Entertainment president Ken Kutaragi talked about some of the various functions and aesthetics of the Cell chip, which will be used in the PlayStation 3. In the article, Kutaragi detailed how the aesthetics of the Cell chip will cut its production costs, as well as how it may also lead to a dual-CPU Cell home server.
Kutaragi stated earlier that although the Cell microprocessor comes with eight synergistic processor elements (SPEs) for multicore processing, the chip only uses seven of them. Kutaragi explained that ignoring one SPE as a redundancy will improve the chip's production yield and allow costs to drop dramatically. In other words, Sony can ship a Cell chip with one defective SPE (out of its eight) as a working product, since the chip only uses seven SPEs to begin with.
"This is the ultimate aesthetic. The number of SPEs we equip to the Cell and how many we will actually use are two different things. I wanted to adopt the idea of 'redundancy' to the development of semiconductors. Logic LSIs, excluding memory chips, are considered defective and unshippable if just one transistor or line doesn't work. If the Cell's final chip dimension is about 200 square millimeters, making one without any defects is extremely difficult. We can't reach our anticipated production yield with that. Of course, we'll take various measures to lower the defect density, but that won't be enough. But by considering one or two SPEs as a redundancy from the very beginning, we can still use a Cell chip even if it's partially defective," Kutaragi said, who also revealed that a similar scheme would also be used for the PlayStation 3's RSX graphics processor.
"An interesting question is what will be done with the Cell chips that only have six working SPEs," continued Kutaragi. "We won't use it for the PS3, of course. Rather, I'm seriously thinking about using two of these chips to create a home server. Home servers have less of a constraint in case size and board dimension when compared to the PS3, and we can make enough space for two Cell chips. That will make it a product with a total of 12 SPEs. This is possible with the Cell since it can use as many SPEs as it needs. And this will bring a use to Cell chips that aren't fit for the PS3."
Kutaragi went on to explain that one of the reasons why the Cell chip for the PS3 was announced to run at 3.2GHz at E3 was due to heat issues. Back when the chip was first announced at the International Solid-State Circuits Conference (ISSCC), its spec said that the chip could run at 4GHz. "We could create a 4GHz Cell if we were aiming to sell it for a high-end computer," Kutaragi said. "There's also the issue of heat. We might have had to create the PS3 with a bigger body if we adopted a 4GHz chip for it."
Kutaragi commented that the PS3's detachable hard drive would most likely be 80GB, since that's the standard capacity of a general 2.5-inch hard drive. "We're going to run an all-purpose OS on it," Kutaragi said, which seems to back up his previous comments that he plans to preinstall Linux on the PS3's HDD.
Kutaragi was asked if he has any plans to add a DVD recorder or home server capability to the PS3. "In that case, you'll need at least one terabyte of disc space" he said. "Even that much space won't be enough if it's going to be HDTV-compliant. To put that much HDD space into this machine is impossible. Rather than to equip some mediocre amount of HDD space, it's better to make it detachable. There's also the possibility of a home server equipped with the Cell chip. But when we first release it as a game machine, we won't need an HDD."
Kutaragi also talked about his decision to adopt Blu-ray for the PlayStation 3 rather than wait a bit longer to see if the Blu-ray and HD-DVD factions would come to a final conclusion on a unified disc standard. "E3 was the last chance," Kutaragi said. "The PS3 is the console of the future, so I wanted an extreme amount of capacity. But for that, we need cutting-edge technology, and not technology that is currently available. My suggestion was to come to an agreement with a physical format that is as close to [the Blu-ray's] 0.1mm as possible. But the PS3 launches in spring 2006. If we had continued to wait for a unified standard, we wouldn't be able to release the PS3. We no longer have any more time. It's game over."
Kutaragi strongly stressed that he has no plans to compromise on the Blu-ray's 0.1mm physical format, which gives it the upper hand to HD-DVD in terms of capacity. However, he said that he could wait until spring 2006 to see if Sony and Toshiba could come up with a unified standard that's still based on the Blu-ray's physical format. As long as the change is only in the disc's logical structure, the PS3 can still adapt to it with some software updates. Despite Kutaragi's comments, it's been reported that Toshiba and Sony are still in negotiations on a standard format.
Kutaragi also talked about the look of the PS3, commenting that he and Teiyu Goto, the console designer of the original PlayStation and the PS2, decided to give the PS3's body a curved surface after considering shapes that hadn't existed in either consoles or computers in the past. When asked if the curved surface made developing internal architecture difficult, Kutaragi said that internal architecture was already being considered when the body was designed, like where the BD-ROM reader's motor and connectors would be placed, as well as how heat would be released. Kutaragi also stated that he prepared three PS3 mock-ups for E3 in silver, white, and black. He settled on the silver one, after gathering a consensus from a variety of different developers and distributors.
"When we released the PlayStation in 1994, Nintendo's Famicom was mainstream," Kutaragi said. "We wanted to create a game machine that wouldn't lose to them, so it's true that we were conscious about the Famicom when we decided on the PS's color and shape. When we released the PS2 in 2000, our goal was to make it blend in naturally with home electronics. We wanted it to be lying around the TV, but not as a game machine, and we worked hard on its DVD playback capabilities. When people used the [original] PS, they'd take it out and unwrap the controller's cord, and then put it back when they were finished playing with it. I hated that. Home electronics always sit right next to a TV, and home electronics are black. So we made sure that the PS2 was black. However, the PS3 will go beyond home electronics and computers. There is no prior example to what the PS3 will be."