IBM SP - Blackforest

Blackforest, a $6.2 million IBM SP RS/6000, was delivered to 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 initially 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 referred to a forested area between Colorado Springs and Denver that 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. Information was exchanged between nodes by message passing.

Blackforest took over much of the computing that had been done by Antero 2, a Cray C90. Over 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 system was upgraded to more than double its initial size in October 2001 with the addition of 164 Winterhawk II nodes and three Nighthawk II nodes for a total of 318 nodes. The expansion was part of the Phase 1 rollout of a new Advanced Research Computing System (ARCS) that would later include another IBM cluster. It 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% as a Winterhawk II system, and 59% in its final configuration in Phase I of ARCS.

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

Blackforest was decommissioned on January 20, 2005, after serving NCAR for more than four and a half years.