This paper studies the memory coherence problem in designing said inaplementing a shared virtual memory on looselycoupled multiprocessors. Two classes of aIgoritb. ms for solving the problem are presented. A prototype shared virtual memory on an Apollo ring has been implemented based on these algorithms. Both theoretical and practical results show tkat the mentory coherence problem cast indeed be solved efficiently on a loosely-coupled multiprocessor.

This paper quantitatively evaluates several alternative approaches to the scheduling of cells in a highbandwidth input-queued ATM switch. In particular, we compare the performance of three algorithms described previously: FIFO queueing, parallel iterative matching (PIM), maximum matching and two new algorithms: iterative round-robin matching with slip (SLIP) and least-recently used (LRU). For the synthetic workloads we consider, including uniform and bursty traffic, SLIP performs almost identically to the other algorithms. Cases for which PIM and SLIP perform poorly are presented, indicating that care should be taken when using these algorithms. But, we show that the implementation complexity of SLIP is an order of magnitude less than for PIM, making it feasible to implement a 32x32 switch scheduler for SLIP on a single chip. 1 Introduction The past few years has seen increasing interest in arbitrary topology cell-based local area networks, such as ATM [5]. In these networks, hosts a...

In this paper we quantitatively evaluate three iterative algorithms for scheduling cells in a high-bandwidth input-queued ATM switch. In particular, we compare the performance of an algorithm described previously -- parallel iterative matching (PIM) -- with two new algorithms: iterative round-robin matching with slip (iSLIP) and iterative least-recently used (iLRU). We also compare each algorithm against FIFO input-queueing and perfect output-queueing. For the synthetic workloads we consider, including uniform and bursty traffic, iSLIP performs almost identically to the other algorithms. Cases for which PIM and iSLIP perform poorly are presented, indicating that care should be taken when using these algorithms. But, we show that the implementation complexity of iSLIP is an order of magnitude less than for PIM, making it feasible to implement a 32 x 32 switch scheduler for iSLIP on a single chip.

Given the multicore microprocessor revolution, we argue that the architecture research community needs a dramatic increase in simulation capacity. We believe FPGA Architecture Model Execution (FAME) simulators can increase the number of useful architecture research experiments per day by two orders of magnitude over Software Architecture Model Execution (SAME) simulators. To clear up misconceptions about FPGA-based simulation methodologies, we propose a FAME taxonomy to distinguish the costperformance of variations on these ideas. We demonstrate our simulation speedup claim with a case study wherein we employ a prototype FAME simulator, RAMP Gold, to research the interaction between hardware partitioning mechanisms and operating system scheduling policy. The study demonstrates FAME’s capabilities: we run a modern parallel benchmark suite on a research operating system, simulate 64-core target architectures with multi-level memory hierarchy timing models, and add experimental hardware mechanisms to the target machine. The simulation speedup achieved by our adoption of FAME—250×—enables experiments with more realistic time scales and data set sizes than are possible with SAME.

Recent anecdotal reports of novel principles of illumination have stressed qualitative aspects. This note presents a quantitative study of an organic illumintation system, characterizing the temperature and current-flow properties of the system as functions of time and device parameters. Theoretical and practical implications of these measurements are discussed. Copyright 1989 Digital Equipment Corporation d i g i t a l Western Research Laboratory 100 Hamilton Avenue Palo Alto, California 94301 USA 1. Introduction There has been a great deal of interest of late in triboluminescence and electroluminescence in organic materials. Triboluminescence in wintergreen Life Savers has been investigated by many over the years [8], while electroluminescence in organic thin films is an active area of current research both here and abroad [10]. In early December 1988, our attention was called to work by Bill Bidermann on electroluminescence in pickles [23]. It was reported that inserting iro...

We use a 1S lattice QCD heavy-light wavefunction to generate a single parameter, model independent description of the Isgur-Wise function. Using recent data we find the zero-recoil slope to be ¸ 0 (1) = \Gamma1:16 \Sigma 0:17, while the second derivative turns out to be ¸ 00 (1) = 2:64 \Sigma 0:74. 1 Introduction The recent development of the Heavy Quark Effective Theory [1] yields an expression for the ¯ B ! D () l¯ l decay rate in terms of a single unknown form factor, the IsgurWise function (IW). This function is absolutely normalized at zero recoil point up to corrections of order 1 m 2 Q [2]. It is currently believed that these corrections can be calculated with less than 5% uncertainty [3], which would allow a precise determination of the CKM matrix element jV cb j from the study of ¯ B ! D () l¯ l decay as a function of the D () meson recoil. In this note we take a somewhat different approach. We use an established LQCD result [4, 5] for the heavy-light wave...

We use a 1S lattice QCD heavy-light wavefunction to generate a single parameter, model independent description of the Isgur-Wise function. Using recent data we find the zero-recoil slope to be 0 (1) = \Gamma1:16 \Sigma 0:17, while the second derivative turns out to be 00 (1) = 2:64 \Sigma 0:74. 1 Introduction The recent development of the Heavy Quark Effective Theory [1] yields an expression for the B ! D () l l decay rate in terms of a single unknown form factor, the IsgurWise function (IW). This function is absolutely normalized at zero recoil point up to corrections of order 1 m 2 Q [2]. It is currently believed that these corrections can be calculated with less than 5% uncertainty [3], which would allow a precise determination of the CKM matrix element jV cb j from the study of B ! D () l l decay as a function of the D () meson recoil. In this note we take a somewhat different approach. We use an established LQCD result [4, 5] for the heavy-light wavefuncti...