Components and Interfaces of a Process Management System for Parallel Programs

Parallel jobs are different from sequential jobs and require a different type of process management. We present here a process management system for parallel programs such as those written using MPI. A primary goal of the system, which we call MPD (for multipurpose daemon), is to be scalable. By this we mean that startup of interactive parallel jobs comprising thousands of processes is quick, that signals can be quickly delivered to processes, and that stdin, stdout, and stderr are managed intuitively. Our primary target is parallel machines made up of clusters of SMPs, but the system is also useful in more tightly integrated environments. We describe how MPD enables much faster startup and better runtime management of parallel jobs. We show how close control of stdio can support the easy implementation of a number of convenient system utilities, even a parallel debugger. We describe a simple but general interface that can be used to separate any process manager from a parallel library, which we use to keep MPD separate from MPICH.Comment: 12 pages, Workshop on Clusters and Computational Grids for Scientific Computing, Sept. 24-27, 2000, Le Chateau de Faverges de la Tour, Franc

Methods to Model-Check Parallel Systems Software

We report on an effort to develop methodologies for formal verification of parts of the Multi-Purpose Daemon (MPD) parallel process management system. MPD is a distributed collection of communicating processes. While the individual components of the collection execute simple algorithms, their interaction leads to unexpected errors that are difficult to uncover by conventional means. Two verification approaches are discussed here: the standard model checking approach using the software model checker SPIN and the nonstandard use of a general-purpose first-order resolution-style theorem prover OTTER to conduct the traditional state space exploration. We compare modeling methodology and analyze performance and scalability of the two methods with respect to verification of MPD.Comment: 12 pages, 3 figures, 1 tabl

Modeling Unemployment Rates by Race and Gender: A Nonlinear Time Series Approach

This paper presents an unemployment rate model that provides insight into how the time series behavior, in terms of both the mean and volatility, of the unemployment rates of black males, white males, black females, and white females differ. Demographic differences in the unemployment rate response are likely to occur if certain demographic groups face discrimination or if different demographic groups gave differing investments in human capital, for example. In addition, there may be differences in other characteristics of the groups, such as differences in the age of distribution or in the marital status distribution. This paper develops and estimates a model to determine whether or not differences in unemployment rate volatility among demographic groups actually exist, utilizing an ARCH-class (autoregressive conditional heteroscedasticity) model. The findings suggest that conditional variance is symmetric for white females, black females, and black males, but is asymmetric for white males. In particular, the findings indicate that innovations increase the conditional volatility changes in each group's unemployment rate and have symmetric effects for all groups except white males.

6- and 5-Halodecaboranes: Selective Syntheses From ClOSO-B10H10(2-) and Use as Polyborane Building Blocks

Decaborane halogenated in the 6-position has been synthesized in high yields via the super-acid induced cage-opening reactions of closo-B10H10(2-) salts. These 6-halogenated compounds were then isomerized to their 5-substituted isomers through base catalysis. The isomerization was driven by the energy differences between the anionic-forms of each respective isomer. These reactions provided 5-halodeboranes in high yields. The bridging-hydrogens of the halodecaboranyl anions were fluxional at a range of temperatures. Variable-temperature NMR studies supported computationally proposed fluxional mechanisms. Both 5- and 6-halodecaboranes were reacted with alcohols yielding boranyl ethers. The mechanisms of substitution, where reactions with 6- and 5-halodecaboranes yielded 5- and 6-boranyl ethers, respectively, were explained computationally and confirmed through isotopic-labeling studies. The regeneration of the polymeric products of ammonia-borane dehydrogenation was carried out through a process that included digestion of the polymer, complexation of the digestate with a base, reduction of B-X bonds to B-H bonds, and finally displacement of the base with ammonia. While digestion schemes proved unable to digest all forms of the dehydrogenated materials, portions of the polymer digested to boron-trihalides were quantitatively regenerated to ammonia borane, with complete separation and collection of by-products

Employment and underemployment of rural people in Grainger County, Tennessee

The objectives of this thesis are to describe the characteristics of the adult population, to determine the extent of underemployment among rural households, to delineate the role of vocational training in preparing rural youths for occupations outside of agriculture, and to point out this country\u27s potential for local urban-industrial development