Jörg Keller

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The Saarbr ucken Parallel Random Access Machine (SB-PRAM) is a scalable shared memory machine. At the gate level it is a re-engineered version of the Fluent machine A. G. Ranade, It uses hashing of adresses, combining and latency hiding. A prototype with 128 processors is presently being designed. In this paper we deal with several problems related to the(More)
We present a fast shared memory multiprocessor with uniform memory access time A rst prototype SB PRAM is running with processors a processor version is under construction A second implementation HPP using latest VLSI technology and optical links shall run at a speed of MHz To achieve this speed we rst investigate the re design of ASICs and network links We(More)
The necessity of a lab course on computer security arises from the students' need to complement course work by hands-on experience. In order to meet the distance teaching demands of our institution, we designed an internet-based laboratory. We sketch the types of tasks the students are to perform, and our approach to check immediately whether students have(More)
Limited bandwidth to off-chip main memory is a performance bottleneck in chip multiprocessors for streaming computations, such as Cell/B.E., and this will become even more problematic with an increasing number of cores. Especially for streaming computations where the ratio between computational work and memory transfer is low, transforming the program into(More)
Lithium concentrations and Li isotope compositions are reported for natrocarbonatites and silicate lavas from Oldoinyo Lengai, Tanzania. Natrocarbonatites are characterized by very high Li contents (211–294 ppm) and a narrow range of δLi values between +3.3 and +5.1. These Li isotope compositions overlap with those reported for MORB and OIB and suggest that(More)