Dr. Horst Simon was named Associate Laboratory Director (ALD) for Computing Sciences at Berkeley Lab in 2004. In his role as the ALD for Computing Sciences, Horst represents the interests of the three computing divisions (NERSC, Computational Research, and Information Technology), in the formulation of Laboratory policy, and communicates Laboratory actions on policy and procedures as appropriate. He also coordinates constructive interactions within the Computing Sciences divisions to seek coupling with other scientific programs.

Horst joined LBNL in early 1996 as director of the newly formed NERSC Division, and was one of the key architects in establishing NERSC at its new location in Berkeley. The NERSC Center is DOE’s flagship supercomputing facility for unclassified research funded by DOE’s Office of Science and is used by 2,819 users at 540 institutions. Under Horst’s leadership, NERSC has enabled important discoveries in fields ranging from global climate modeling to astrophysics. Horst is also the founding director of Berkeley Lab's Computational Research Division, which conducts applied research and development in computer science, computational science, and applied mathematics.

Horst’s research interests are in the development of sparse matrix algorithms, algorithms for large-scale eigenvalue problems, and domain decomposition algorithms for unstructured domains for parallel processing. His recursive spectral bisection algorithm is regarded as a breakthrough in parallel algorithms for unstructured computations, and his algorithm research efforts were honored with the 1988 Gordon Bell Prize for parallel processing research. Horst was member of the NASA team that developed the NAS Parallel Benchmarks, a widely used standard for evaluating the performance of massively parallel systems. He is also one of four editors of the twice-yearly “TOP500” list of the world’s most powerful computing systems.