Cell companion chip gets hot demo

Toshiba showed off a "super companion chip," or SCC, for the Cell that can record 48 separate MPEG 2 streams at once.

The chip, detailed at the Hot Chips conference taking place at Stanford University this week, is part of an effort by developers of the SCC and the Cell--IBM, Toshiba and Sony--to get the Cell into as many types of devices as possible.

The SCC is essentially a versatile, high-speed input-output port, according to Takayuki Mihara, an engineer with Toshiba. It receives regular and high-definition TV signals, audio and other data from set-top boxes, hard drives and similar items, and then forwards it to the processor.

"The Cell processor needs access windows to communicate with outside modules," Mihara said. "I think the Cell processor will be used in multiprocessor-centric systems such as digital TV. In reality, not many will try to record all that video at once, but it makes for a cool demo."

Cell engineers also emphasized that they designed the Cell processor--and its corresponding helper chips--to ensure smooth audio and video programming.

The Cell, for instance, partitions a single video image into five elements, which then get processed on three separate streams, said Ryuji Sakai of Toshiba. The chip also comes with a bandwidth reservation feature that can allocate bandwidth dynamically to different subcomponents of the chip. Better bandwidth scheduling leads to higher performance.

The SCC sports a wide array of input/output systems. A single chip comes with four USB ports, two serial ATA ports, four PCI slots and a PCI (peripheral component interconnect) express link, and its own memory. The SCC will communicate directly with the Cell chip over a Flex I/O link, designed by Rambus, which can pass 5GB of data per second each way.

Mihara said that the SCC would likely be included in computer systems and audio-visual equipment running Cell, but he did not specifically state which products the SCC would be used in.

Sony has committed to including Cell in the next version of the PlayStation game console. Toshiba, meanwhile, has said it will include the Cell in future TVs.

So far, one company outside the Cell triumvirate--Mercury Computer Systems--has announced that it will put the chip into its computers geared toward oil and gas engineers and other power users. Researchers and executives have said they will promote the chip for a variety of projects, and different versions of the chip will come out for different markets.

"This is not a single-application processor," said Michael Gschwind from IBM. "It will be used in consumer electronics, supercomputers, home servers ...We can span a whole range of devices with multiple flexibility."

Still, spreading the Cell message won't be easy. The chip is just out and a lot of programming work lies ahead, noted Kevin Krewell, editor in chief of the Microprocessor Report. Sakai got a laugh out of the audience when he concluded his presentation with, "Have fun programming on the Cell!"

Nathan Brookwood of Insight 64 also was puzzled by some features of the SCC. It uses DDR (double data rate) 2 memory. The Cell itself connects to XDR (external data representation) memory, a different architecture of memory developed by Rambus. In the end, that means two chips working closely together will use two different types of memory.