Strindberg

Strindberg was an IBM SP2 distributed memory supercomputer system that was installed at PDC in 1994. The system was upgraded quite a few times and the final version of the system contained IBM Power2, PowerPC and Power3 nodes. At the end of 2003, the Power2 and PowerPC nodes were decommissioned. The part of the system with the Power3 nodes stayed in operation for a while longer and was known as Nighthawk.

The IBM Scalable POWERparallel (SP) series of supercomputers were part of the IBM RISC System/6000 (RS/6000) family and were also known as RS/6000 SP systems. The SPs consisted of multiple RS/6000-based nodes connected to each other through a device known as a switch.

An IBM SP2 supercomputer was installed at PDC in 1994 and the system was named after August Strindberg , a Swedish author and playwright who was also a painter. The system was significant in the evolution of supercomputing systems for academic research in Sweden as the many upgrades to the system spanned much of the move from high-speed serial processing to the increasing adoption of parallel processing and the development of parallelisation techniques for coding.

The Strindberg system went through several significant upgrades during its lifetime. It started as a 55-node system that was 97th in the June 1995 Top500 list . Then, early in 1996, the number of nodes was increased to 96 and the existing nodes were upgraded with faster processors and more memory. In addition, a mass storage system was acquired which increased the amount of available disk storage.

The 96-node version of Strindberg had the following specifications.

80 × T2 nodes
16 × wide nodes
380 GB user available disk
peak performance 267 MFLOPS per node
peak performance (for the whole system) 25.6 GFLOPS
total memory 18.5 GB

This system was the largest IBM SP2 outside the USA at the time, which meant that, for the first time in many years, there was a high-performance computer of international class in Sweden. This system was 64th in the June 1996 Top500 list . Later that year, in October 1996, the number of nodes in Strindberg was increased to 110, so the system was capable of a peak performance of 29 GFLOPS and had 20 GB of memory. That system came 80th in the November 1996 Top500 list .

There was a major upgrade of Strindbeg in November 1997. The upgrade involved all parts of the system: the peak CPU performance of each batch node was increased by a factor 2.5, the amount of available memory grew by a factor of 2 and the network bandwidth by a factor 3, plus the number of nodes was increased from 110 to 122.

In January 1998, the system was upgraded yet again, resulting in it having a total of 146 nodes as follows.

130 × 160 MHz (640 MFLOPS) T4 nodes
16 × wide nodes
around 720 GB user available disk space
total memory 47.6 GB
peak performance (for the whole computer) is 87.7 GFLOPS

With its 130 new 160MHz nodes together with 16 of the old wide nodes, the 146-node version of Strindberg comprised a very powerful supercomputer for that time which came 60th in the June 1998 Top500 list .

As part of a research collaboration between IBM and PDC, it was also decided to add symmetric multiprocessor (SMP) nodes to the system in the spring of 1998. The six new SMP nodes (known as M nodes) that were added to Strindberg were each equipped with four IBM Power PC 604e 332 MHz CPUs. Each SMP node had an aggregated peak floating point performance of 2,656 MFLOPS, which gave an aggregated performance of more than 100 GFLOPS for the system as a whole with an aggregated memory bandwidth of 441 GFLOPS. The purpose of the collaboration was to investigate the applicability of SMP technology in general and, in particular, to evaluate the benefits of parallel SMP systems for several specific scientific codes.

In March 1999, Strindberg underwent another major upgrade of systems and hardware in which sixteen more SMP nodes were added. A further upgrade later in 1999 added 8 Nighthawk Power3 nodes. The resulting system had 178 nodes:

148 × IBM Power2 SuperChip (P2SC) nodes,
22 × SMP nodes, each with 4 × IBM PowerPC 604e CPUs, and
8 × IBM Nighthawk Power3 nodes.

The new Nighthawk nodes had the following important features.

8 CPUs per node which shared the same memory
4 GB of memory per node with one node having 16GB of memory
16 GB of scratch file space for intermediate files

The overall system had about 2,000 GB of disk available to users and the peak performance of the system was 204 Gflop/s with a the total memory of 115 GB. The part of the system with the Nighthawk nodes could be used separately to the rest of the system. It was referred to SP-NH and came 350th in the November 1999 Top500 list .

Later the SP-NH part of the system was upgraded to have 11 Nighthawk nodes, each of which contained 8 or 16 IBM Power3 CPUs, giving a total of 112 CPUs as follows.

7 nodes, each with 8 IBM Power3 CPUs and 4,096 MB RAM
1 node with 8 IBM Power3 CPUs and 16,384 MB RAM
3 nodes, each with 16 IBM Power3 CPUs and 16,384 MB RAM

The nodes were interconnected by an IBM SP Switch2. There was over 380 GB of additional disk storage available for user data through the shared parallel file systems (280 GB for projects and 100 GB for scratch storage) and plenty of space in the distributed file systems for user home directories, application codes and so forth.

Strindberg was used both as a computational server (using the nodes as powerful individual computational processors) and for parallelisation projects. Information for users of the system at that time noted the following.

“To attain fast throughput, you can also have several nodes work simultaneously on one program. You get exclusive access to a number of processors, for the duration of a job. Parallelization of an existing program, or the development of a parallel program, can be quite cumbersome. Take full advantage of available expertise at PDC. In the context of a project, a PDC support team can work with you on the parallelisation of your software. ”

The six older cabinets of Strindberg that were not moved to PDC’s new location, photographed at PDC’s previous location at Osquars Backe on 20 January 2004.

With all the upgrades and expansions of the system, Strindberg ended up being housed in many cabinets (also referred to as racks or frames). In December 2003, PDC was relocated to a different building at KTH (namely PDC’s current location at Teknikringen 14), and the parts of the Strindberg system with the Power2 and PowerPC nodes were shut down. The three cabinets with the Nighthawk Power3 nodes were moved to the new PDC computer hall in the basement of Teknikringen 14 where they ran for another year or so as a system known as Nighthawk.