Date of Award

Fall 1984

Document Type

Thesis - Restricted

Degree Name

Master of Science (MS)


Electrical Engineering and Computer Science

First Advisor

Riedel, Susan

Second Advisor

Heinen, James


The purpose of this thesis is to develop and present the concept of building a computing environment giving both the user and the software a large amount of flexibility This environment should be built utilizing existing centralized multiuser facilities as its core. The key points of the environment are: 1. Foremost, provide all users no less capabilities than they currently have. 2. Allow users to access the growing wealth of software available for personal computers. 3. Allow more efficient utilization of the host by increasing its recommended maximum number of users. 4. Provide fast response in highly interactive applications (such as screen editors and word processing). 5. Provide all this at little or no cost increment over the cost of the existing host equipment and remote access terminals. The idea of this project is to give users all the above features as inexpensively as possible. This is done by saving the investment already put into centralized computer facilities. The system described is in reality two separate environments on one computer system. The first environment consists of the existing multi.user facilities; although enhanced, this environment should seem exactly the same to the user as it was before. A user who accesses only this environment may never know that changes have been made, or even that the other environment exists. The second environment provides users with local computing capabilities much the same as personal computer systems, but provides the rich peripheral resources of the host, Because these resources are shared, each user has a wider selection of peripheral devices and increased mass storage, while the expense of these resources is shared among all users. The facilities I used in the implementation of this environment consisted of four PDP* 11/70s, each running the UNIXt operating system, and a high speed network of downloadable terminals. To implement the local processing capabilities, a version of the CP/Mt (Control Program for Microcomputers) operating system that had been adapted to the network was used to download into the terminals. Users are allowed access to the host by downloading software into the remote terminals that provides basic terminal functions. This software allows the user to access the terminal in the same manner as a basic terminal connected to the host, allowing all the capabilities that the user previously had. One enhancement that the user is aware of is the high-speed interface to the host. Downloading the CP/M operating system into the remote terminals allows users to access any available CP/M applications. These applications run in the terminal, using the host only for mass storage and peripheral access (such as printing). This paper is divided into several segments. The first section presents some background on operating systems and networks, while the second section discusses some of my views of the changing computing environment. The third section presents the hardware, network and operating system used in this project, and the last section will present some views on further enhancements to the system developed, end a discussion of the deficiencies of the current implementation. Included In the appendices is a short description of the software written and a listing of the source for the BIOS section of the CP/M operating system. Also included in the appendix is the source for the program on the host that provides the remote operating system with mass storage and peripherals.



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