METRICS

The recently introduced Extended Architecture (XA) of large IBM computer systems includes, in the disk I/O area, the ability for an access to be resumed and completed on a path different from the one on which it has been initiated. The expected disk ...

A Mean Value Analysis (MVA) approximation is presented for computing the average performance measures of closed multiclass queueing networks containing non pre-emptive Head Of Line (HOL) and Pre-empt Resume (PR) priority centers. The approximation has ...

The BLI-model of program behaviour is sometimes referred to as an exact measure of the locality structure of the programs. However, only limited experimental data is available of the applicability of the BLI-model. In this paper the characteristics of ...

The STOCHOPT automatic file migration policy (proposed by A.J. Smith) minimizes the expected retention and recall costs of an abitrarily sized file. We consider the application of the STOCHOPT policy to a file system in which the file inter-reference ...

A high-performance personal computing environment must avoid perceptible pauses resulting from many page faults within a short period of time. Our performance goals for a paged virtual memory system for the Smalltalk-80^TM@@@@; programming environment ...

An important problem in queueing network modeling is that of characterizing and analyzing relationships among alternative models of a single system. The problem is approached by developing the concept of a state space transformation, which is a ...

There are two basic representations of workload populations in load independent, separable queueing network models. These correspond to the notions of open and closed classes, an open class being one in which customers may arrive and depart the model, ...

The effect of concurrency control methods on the performance of computer systems is analyzed in the context of a centralized database with a static lock request policy, i.e., database transactions should acquire all locks before their activation. In the ...

In this paper we focus on the storage resource. A basic model of the space time requirements of jobs in a computer system is described, and a number of its variations analyzed by means of diffusion approxmiations. Subject to the usual heavy traffic ...

There are many situations where information about the transient behaviour of computer systems is wanted. In this paper a diffusion approximation to the transient behaviour of some queueing systems is proposed. The solution of the forward diffusion ...

A widely used error recovery technique in database systems is the rollback and recovery technique. This technique saves periodically the state of the system and records all activities on a reliable log tape. The operation of saving the system state is ...

In this paper we derive a formula for the moments of the residual life in operational context, and show that the Paradox of Residual Life holds also in a finite queueing model. In addition, we prove the renewal theorem, show that forward and backward ...

Predicting important performance parameters of computer networks, recognizing potential bottlenecks, comparing design alternatives are factors of decisive importance in building complex computer networks. In this respect, computer aided simulation has ...

Problems related to the evaluation of computational speeds of supercomputers are discussed. Measurements of sequential speeds, vector speeds, and asynchronous parallel processing speeds are presented. A simple model is developed that allows us to ...

The aim of this paper is to present some measurements on the performance of a X.25 packet switching subnetwork and of a typical X.25 DTE-DCE interface. The communication parameters considered are the window size of the link layer flow control, the ...

Multiprocessors are beginning to be regarded increasingly favorably as candidates for controllers in critical real-time control applications such as aircraft. Their considerable tolerance of component failures together with their great potential for ...

Recent developments in very large scale integration have made it feasible to construct a highly parallel computer composed of large numbers of interconnected microcomputers. The modeling problems posed by this approach to parallel processing differ in ...

Graph models have been proposed by many authors as a useful tool for the analysis of peculiar features of computer systems such as concurrency, synchronization, communication, and cooperation among subsystems. Much of the work in this field is related ...

In this paper we present a mathematical model to compute the bandwidth of the multiple bus interconnection network. Due to the computational complexity associated with the exact solution, the processors are removed from the queues at the end of each ...

This paper presents an approximate analysis of a multiprocessor system consisting of P processors, M memory modules, and B buses. The model assumes constant memory access times, arbitrary memory access patterns, and bus contention. The solution ...

A new aggregation approximation procedure is presented for analyzing single class closed queueing networks with simultaneous resource possession. It is applicable to multiple entry systems such as I/O models and relies on a new multi-entrance queue to ...

Prediction of detailed characteristics of the time delays experienced by customers in queueing networks is of great importance in various modelling and performance evaluation activities: operations research, computer systems and communication networks. ...

This paper is based on a recent technique called perturbation analysis of discrete event systems. The aims of the paper are two-fold. The first, is to bring this technique, which is still relatively new, to the attention of a wider audience, since the ...

A class of policies called stationary delayed resolution policies have been proposed recently for sharing finite number of buffers at a store-and-forward node in a message switching network [9]. It has been shown that with respect to the total weighted ...

This paper presents a simple heuristic analytic algorithm for predicting the “response times” of messages in asymmetric token ring local area networks. A description of the token ring and the model is presented in section 2 the algorithm is described in ...

A tandem queue model is developed that models the end-to-end delay behavior in networks that employ sliding window flow control. Messages arriving to find the window filled are assumed to be queued outside the network to await their turn to enter. The ...