Cray-4

Cray Computer Corporation

Industry	Supercomputing
Defunct	1995
Fate	Bankruptcy
Key people	Seymour Cray (designer)
Products	Cray-4 supercomputer

The Cray-4 was developed as the follow-up to the unsuccessful Cray-3 supercomputer by Cray Computer Corporation, with the goal of rivaling the T90 model from Cray Research. Despite these ambitions, CCC went bankrupt in 1995 before any units were delivered.

Design

Following the Cray-3, which marked the initial major application of gallium arsenide (GaAs) semiconductors in computing but had limited deployment with only a single unit produced, Seymour Cray introduced the Cray-4 concept in 1994. This new design was smaller and faster, scaling from four up to sixty-four vector processors operating at 1 GHz, a significant increase compared to the Cray-3's four to sixteen processors running at 474 MHz. The architecture was compact enough to fit within , and utilized the smaller one-CPU "tanks" originally developed for the Cray-3 during testing. A midrange setup consisted of 16 processors, 1,024 megawords (equivalent to 8,192 MB) of memory, and achieved 32 gigaflops performance, with an estimated cost of $11 million.

Unlike previous models, the Cray-4 discarded the local memory design and instead reverted to employing an extensive set of B- and T-registers due to difficulties in effectively leveraging local memory.

1994

Throughout 1994, considerable advancements were made on the Cray-4 by building upon technologies from the Cray-3. The company announced plans for its market release on November 10, 1994. Several single-processor prototypes equipped with 64 megawords of memory underwent diagnostic evaluations before development was interrupted by bankruptcy. Early in 1994, CCC initiated testing of individual modules and aimed to produce a four-processor prototype by mid-1995; however, all progress ceased following their bankruptcy filing.

Legacy

In September 2015, processor serial number 001 was auctioned for $37,500 and is thought to be the sole surviving Cray-4 unit. Additionally, prototype CPU components and promotional materials remain preserved.