UNIVERSITY of CALIFORNIA SANTA CRUZ NON-VOLATILE CACHE MANAGEMENT FOR IMPROVING WRITE RESPONSE TIME WITH ROTATING MAGNETIC MEDIA

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A Stack Model Based Replacement Policy for a Non-Volatile Write Cache

The use of non-volatile write caches is an effective technique to bridge the performance gap between I/O systems and processor speed. Using such caches provides two benefits: some writes will be avoided because dirty blocks will be overwritten in the cache, and physically contiguous dirty blocks can be grouped into a single I/O operation. We present a new block replacement policy that efficiently expels only blocks which are not likely to be accessed again and coalesces writes to disk. In a series of trace-based simulation experiments, we show that a modestly sized cache managed with our replacement policy can reduce the number of writes to disk by ?? percent and often did better. We also show that our new policy is more effective than block replacement policies that take advantage of either spatial locality or temporal locality, but not both

Abstract

The use of non-volatile write caches is an effective technique to bridge the performance gap between I/O systems and processor speed. Using such caches provides two benefits: some writes will be avoided because dirty blocks will be overwritten in the cache, and physically contiguous dirty blocks can be grouped into a single I/O operation. We present a new block replacement policy that efficiently expels only blocks which are not likely to be accessed again and coalesces writes to disk. In a series of trace-based simulation experiments, we show that a modestly sized cache managed with our replacement policy can reduce the number of writes to disk by percent and often did better. We also show that our new policy is more effective than block replacement policies that take advantage of either spatial locality or temporal locality, but not both.

Abstract REINAS: the Real-Time Environmental Information Network and Analysis System

and Analysis System (REINAS) is a distributed system supporting the conduct of regional environmental science research at the desk top. Continuous real-time data acquired from dispersed sensors is stored in a logically integrated but physically distributed data base. An integrated problemsolving environment is under development which supports visualization and modeling. REINAS is intended to provide insight into historical, current, and predicted oceanographic and meteorological conditions. REINAS permits both collaborative and single-user scientific work in a distributed environment

An Architecture Supporting Real-Time and Retrospective Environmental Data Management

The Real-Time Environmental Information Network and Analysis System (REINAS) is a distributed database environment supporting both real-time and retrospective regional scale environmental science. Continuous real-time data is acquired from dispersed sensors and input to a logically integrated but physically distributed database. An integrated problem-solving environment supports visualization and modeling by users requiring insight into historical, current, and predicted oceanographic and meteorological conditions. REINAS supports both collaborative and single-user scientific work in a distributed environment. The goals and design of key data management aspects of REINAS are described

REINAS: A Real-time System for Managing Environmental Data y

Managing scientific data is a challenging task, and many of the problems it presents have yet to be adequately solved. The Real-time Environmental Information Network and Analysis System (REINAS) is an operational solution to the problem of collecting and distributing environmental data in a real-time context, as well as supporting data acquisition, retrieval, visualization and long-term data maintenance. The system is built around one or more databases and has been developed to support both real-time and retrospective regional scale environmental science. Continuous real-time data is acquired from dispersed sensors and input to a logically integrated but physically distributed system. The database engine provides a powerful structure to handle data management, but current database technology can have difficulty meeting the performance requirements that a large real-time environmental system demands. The REINAS architecture and current status is described in detail, including the challenges that were addressed in the construction of an operational system which includes a regional wireless instrumentation network comprised of over 70 instrument platforms and 220 sensor streams producing real-time data of interest to thousands of users in 1996

REINAS: A Real-time System for Managing Environmental Data

Managing scientific data is a challenging task, and many of the problems it presents have yet to be adequately solved. The Real-time Environmental Information Network and Analysis System (REINAS) is an operational solution to the problem of collecting and distributing environmental data in a real-time context, as well as supporting data acquisition, retrieval, visualization and long-term data maintenance. The system is built around one or more databases and has been developed to support both real-time and retrospective regional scale environmental science. Continuous real-time data is acquired from dispersed sensors and input to a logically integrated but physically distributed system. The database engine provides a powerful structure to handle data management, but current database technology can have difficulty meeting the performance requirements that a large real-time environmental system demands. The REINAS architecture and current status is described in detail, including the chall..