Star processor

IBM's Star processor is a reduced instruction set computer (RISC) processor that is available in several series versions for IBM's AS/400 and RS/6000 systems. The three processors in the Star Series are the Northstar, the Pulsar, and the Silicon-On-Insulator (SOI) processor.

The first in the Star Series, the Northstar processor, is superscalar, which means it can execute multiple instructions per clock cycle, and includes two 64 Kbps on-chip level-one (L1) caches. Its operating frequency is 262 MHz, and it has a 162 mm2 die size. It uses 27 watts of power. The Northstar processor is based on traditional complementary metal-oxide semiconductor (CMOS) fabrication technology. It is often called the A50 processor in AS/400 systems and the RS64-II processor in RS/6000 systems.

The Pulsar is the second Star Series processor. It is based on a combined copper and silicon fabrication technology, which affords more operating speed using less power. Its operating frequency is 450 MHz, and it has a 140 mm2 die size. It includes two 128 Kbps on-chip L1 caches and operates on 24 watts of power. The Northstar processor was the basis for the Pulsar. The Pulsar powers the RS/6000 S80 system. It is often called the RS64-III processor.

The final Star Series processor is the Silicon-on-Insulator-based processor used in the AS/400 iSeries server. SOI-based processors are manufactured using pure silicon and silicon oxide. The operating frequency is 550 MHz, and it has a 140 mm2 die size. It includes two 128 Kbps on-chip L1 caches and uses 22 watts of power.