METRICS

Our understanding of several allocation algorithms basic to operating systems and to data base systems has improved substantially as a result of a number of research efforts within the past one or two years. The results have stirred considerable ...

The principles on which artificial workload model design is currently based are reviewed. Design methods are found wanting for three main reasons: their resource orientation, with the selection of resources often unrelated to the performance impact of ...

A file assignment case study of a computer system running Unix is presented. A queueing network model of the system is constructed and validated. A modeling technique for the movement of files between and within disks is proposed. A detailed queueing ...

Although the phenomenon of locality has long been recognized as the single most important characteristic of program behaviour, relatively little work has been done in attempting to measure it. Recent work has led to the development of an intrinsic ...

The Lineariser is an MVA-based technique developed for the approximate solution of large multiclass product form queueing networks. The Lineariser is capable of computing accurate solutions for networks of fixed rate centres. However, problems arise ...

Queueing network performance modelling technology has made tremendous strides in recent years. Two of the most important developments in facilitating the modelling of large and complex systems are hierarchical modelling, in which a single load dependent ...

Response Time Preservation (RTP) is introduced as a general technique for developing approximate analysis procedures for queueing networks. The underlying idea is to replace a subsystem by an equivalent server whose response time in isolation equals ...

We define and evaluate two policies (NA-policy, A-policy) for parallel execution of program tree structures. Via a probabilistic model we analytically determine, for each policy, the Laplace-Stieltjes transform for the tree processing time distribution. ...

The Amdahl 580 processor is a pipelined processor whose performance can be affected by characteristics of the instructions it executes. This paper describes certain optimizations made to a set of system software routines during their development. The ...

This report describes an experimental disk block server implemented for the RSX-11M Operating System using DECnet. The block server allows user programs on one system to access files on a disk physically located on a different system. The actual ...

In this paper a performance study of the access channel in a cellular mobile telephone system /1/ is presented. The method used in the Cellular System for multiplexing the population of mobile terminals over the access channel is a hybrid between the ...

A distributed program consists of processes, many of which can execute concurrently on different processors in a distributed system of processors. When several processes from the same or different distributed programs have been assigned to a processor ...

The time required to find the exact solution of a product-form queueing network model of a computer system can be high. Faster and cheaper methods of solution, such as approximations, are natural alternatives. However, the errors incurred when using an ...

We propose a new 'building block', for analyzing queueing networks. This is a model of a server with a variable buffer-size. Such a model enables efficient analysis of certain queueing networks with blocking due to limited buffer spaces, since it uses ...

We consider a probabilistic model of locking in a database system in which an arriving transaction is blocked and lost when its lock requests conflict with the locks held by currently executing transactions. Both exclusive and shared locks are ...

This paper describes a hybrid model, combining both analytical and simulation techniques, which was developed to study the performance of a netted computer based system. The computer based system that was modeled is the Facility Assignment and Control ...

The scheduler used in an operating system is an important factor in the performance of the system under heavy load. This paper describes the scheduling philosophy employed in the UNIX operating system and outlines the standard scheduling strategies. ...

The token bus based local area network, REDPUC, designed and implemented at the Pontíficia Universidade Católica do Rio de Janeiro is briefly described. Analytic models are presented, which allow one to obtain an approximation for the average packet ...

Token rings and multipoint polled lines are two widely used network interconnection techniques. The general concept of cyclic allocation processes is defined and used to characterize token passing and polling in these networks. Scan time, the time to ...

Queueing network models of multiprogramming systems with memory constraints and multiple classes of jobs are important in representing large commercial computer systems. Typically, an exact analytical solution of such models is unavailable, and, given ...

Approximations are given for the mean response times of each priority level in a multiple-class multiserver M/G/m queue operating under preemptive resume scheduling. The results have been tested against simulations of systems with two and three priority ...

Queueing Network Models - QNM's with population size constraints and delayed blocked customers occur due to MultiProgramming Level - MPL constraints in computer systems and window flow-control mechanisms in Computer Communication Networks - CCN's. The ...