IBM SP RS/6000

Clock Speed: 
Dates Used: 
Wednesday, August 11, 1999 to Monday, January 10, 2005
Microprocessor Peak Teraflops: 
Memory (terabytes): 
Number of Processors: 
1 308.00
Electrical Power Consumption: 
140.00 kW

A $6.2 million IBM SP RS/6000 named blackforest was installed at NCAR on August 11, 1999. Use of the computer was equally divided between NCAR's community users and the Climate Simulation Laboratory.

The SP was made up of eight tall black boxes — a virtual "black forest" of computers. Following a tradition of naming NCAR computers after Colorado landmarks, its name also refered to the forested area along the Palmer Divide between Colorado Springs and Denver, which includes the town of Black Forest.

For NCAR, the arrival of the SP began a transition to clustered shared-memory processors. Blackforest was a distributed-memory clustered machine consisting of many nodes in which memory was shared by the processors within the nodes. Between nodes, information was exchanged by message passing.

Blackforest took over much of the computing that formerly had been done by antero, the CRAY C90. Over the course of its lifetime, blackforest provided scientists with a platform to study global climate change, droughts, long-range weather prediction, atmospheric chemistry, and space weather.

In its initial configuration, blackforest had 148 Winterhawk I nodes, each with two processors, and a peak speed of 237 gigaflops. In May 2000, its 148 Winterhawk I nodes were replaced with 151 Winterhawk II nodes, bringing the system's peak speed to 906 gigaflops.

The following year, in October 2001, the system more than doubled in size, with the addition of 164 Winterhawk II nodes and three Nighthawk II nodes for a total of 318 nodes. This expansion, part of a the Phase I rollout of a new Advanced Research Computing System (ARCS) that would later include another IBM cluster, gave blackforest a peak speed of 1.962 teraflops — again more than doubling the computational power available to NCAR researchers.

In total, blackforest spent 14% of its life as a Winterhawk I system, 27% of its life as a Winterhawk II system, and 59% of its life in its final configuration as Phase I of ARCS.

The system ran the AIX operating system and supports Fortran (95/90/77), C, and C++ compilers. It ran LoadLeveler as its batch subsystem.