【NEC】 ACOS System 2000 Series

In February 1986, NEC announced a series of ultra-large general-purpose computers which were the largest and fastest in the world at the time -- the ACOS System 2000 Series. This series employed a range of LSI technology including: ultra high-speed logic LSI (CML) with 1,000 gates and a delay time per gate of 100 picoseconds, ultra high-speed high-integration logic LSI (CML) with 4,000 gates and a delay time per gate of 170 picoseconds, 16-kilobit ultra high-speed bipolar RAM with an access time of 3 nanoseconds, and 1-megabit DRAM. It also employed packaging technology to enable installation of a maximum of 42 LSIs on a 10-centimeter-square multi-layer ceramic substrate, and used a direct liquid cooling system which performed cooling with liquid instead of air (as in previous machines). It also employed innovations such as the pipeline system and the integrated array processor system. This approach made the series the largest and fastest in the world.

The series also achieved high availability by employing approaches such as independent processors specially designed for RAS, a wide range of automatic retry functions (for everything from input-output commands to firmware instructions), processor relief functions and dynamic reconfiguration functions. These systems had hot standby capability to enable automatic and instantaneous switching to a standby system when a problem occurred in a loosely coupled multiple processor system, and a fault tolerant capability to enable processing with a normal system even in a load distribution loosely coupled multiple processor system where multiple processors perform online processing simultaneously. This made it possible to build highly reliable systems.

Artificial intelligence (expert systems) was used to facilitate computer management and use, even by persons without specialized knowledge.