Inexpensive Terminals Research Articles

Electronic Information Delivery Systems: Reports on Five Projects Sponsored by the Fred Meyer Charitable Trust

The Fred Meyer Charitable Trust, Division of Library and Information Resources for the Northwest, has funded five research projects that will demonstrate the potential of various techniques and new technologies to facilitate communications and resource sharing in the Northwest. The experience and information derived from these projects will be of value to all libraries and information centers, not just those conducting the research. The techniques and technologies being evaluated include: simultaneous remote searching, which uses inexpensive terminals and modems; a mini‐computer‐based union list and resource sharing network (INFONET); networks using facsimile machines; networks that transmit documents that have been optically scanned into bit‐map image files; and use of optical character recognition equipment to capture ASCII machine‐readable information that can be broadcast by television stations to user‐sites. Contributors of reports are: Verl Anderson, Linda Brander, Millard F. Johnson, Jr., Bruce Morton, and Steve Smith. Summary observations are provided by Joseph R. Matthews.

The Geostar System

The Geostar satellite navigation system is designed to provide a number of user services through inexpensive terminals (transceivers). The services include precise positioning, location radio (the reporting of position back to a fleet headquarters), digital message transmission both send and receive, and connection to non-Geostar digital communications systems through a single node point. A number of additional user services (terrain and shoreline avoidance, warnings of hazards to navigation, ship or aircraft collision avoidance, emergency location and rescue communications, etc.) are provided relatively inexpensively because all messages and positionings in Geostar flow through a single location where powerful computers are available.

TORNET

TORNET is an experimental local area computer network presently being designed and built in the Computer Group Laboratory of the Department of Electrical Engineering at the University of Toronto. The network consists of a number of local rings, each attached to a central ring. The local rings employ a variation on the slotted-ring format that uses a limited insertion technique to achieve reasonable response times for character traffic among many devices and small computers. Two fixed-length packet formats (one byte or 128 bytes of data) are used on the local rings. Only the longer format is used on the central ring which generally provides record level access to shared specialized equipment. The main objective in the local ring design is a low-cost port for inexpensive terminals, sensors, etc. The paper concentrates on the functional characteristics of the local rings, including delay-throughput comparisons with other well-known ring schemes.

Greenprint: A graphic representation of structured programs

GREENPRINT as a graphics representation of program control structure is unique in that its objects—blocks and boxes—appear from top to bottom in the same order as the associated program text. The two representations can thus be studied and worked with concurrently. Other advantages, some shared by conventional flowcharts and NSDs, include the capability of automatically generating GREENPRINTs from program text and generating control statements from a GREENPRINT. GREENPRINTs can be displayed on inexpensive terminals. In addition, the exactness of GREENPRINTs suggests the possibility of developing program complexity metrics based on purely geometric properties. But this and the extension of the GREENPRINT approach to include structure and flow of data remain interesting research topics at this time-