الفهرس 
AcknowledgmentOnly 14 pages are availabe for public view
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Abstract
Mass storage devices are important elements of time shared and multiprogrammed computer systems because they provide the storage for both the permanent system and user files and the temporary files necessary for compilat ions, assemblies, etc.
Since the performance of a computer system is .dependent on the speed with which files can be accessed, the mass storage devices of a system can have a significant effect on its overall performance.
Thus it is important to st udy the behavior of mass storage devices and to develop models of their behavior from wh.ich performance predictions can be derived.
The disk storage devices are attractive because of their size, speed and cost, as compared with alternatives such as magnetic tape or card devices.
The aim of this thesis is to study and evaluate the performance of disk storage devices. The study is focused on the methods of decreasing the mean response time of disk system and thus improving the performance of the overall computer system.
A simulation model is built to represent the disk storage system and from which performance predictions can
be drawn.
Some parameters of the load on the system are obtained from measurements taken via a software monitor that runs on the PDPll/70 to owned by the University of Alexandria.
First it is necessary to be familiar with the tools employed in
a study like this, thus the first chapter of is a survey on the performance evaluation that are used to carry on any performance study. Among these tools is the simulation technique that is used in our study. Also the performance
nitoring technique are explored in order to understand
be methods of collecting data about the operation of the mputer system and its components.
thesis .techniques
In order to make a study on a certain subject, it is
that previous work in that area be carefully
this point of view, a survey on the performance of disk storage 1n chapter two.
is used in our study is the with the RP06 disk drives. A survey on the basic of the disk storage syste~ of •that system is in chapter three. Thi s allows us to be fami liar structure and operation of the system under study.
Chapter four discusses the modeling of the disk system. The modeling includes a simulation model