A new birth always has about it an aura of excitement that be matched by few other spectacles. This is true whether the birth is that of a new being, a new world or a new idea. The excitement arises not so much from the mere fact of birth but rather from the uncertainty and the element of doubt as to the future that always surround a novel event. In this connections, workers in the field computers are now becoming increasingly excited about the birth of a remarkable new method for the distribution and utilization of computer power. This method has been given a variety of names including 'computer utility'.
Regardless of the name, however, the development of this method does open up exciting new prospects for the employment of computers in ways and on a scale that would have seemed pure fantasy only five year ago.
Even now the subject of computer utilities is very much in the public eye, as evidenced by many articles in both the popular and technical press, prognostications by leading industrial and scientific figures and growing signs of interest on the part of governments everywhere.
The word 'utility' in the term 'computer utility' has, of course, the same connotation as it does in other more familiar fields such as in electrical power utilities or telephone utilities and merely denotes a service that is shared among many users, with each user bearing only a small fraction of the total cost of providing that service. In addition to making raw computer power available in a convenient economical form, a computer utility would be concerned with almost any service or function which could in some way be related to the processing, storage, collection and distribution of information.
A computer utility differs fundamentally from the normal computer service bureau in that the services are supplied directly to the user in his home, factory or office with the user paying only for the service that he actually uses.
The computer utility is a general purpose public system that includes features such as :-
- Essentially simultaneous use of the system by many remote users.
- Concurrent running of different multiple programs.
- Availability of at least the same range of facilities and capabilities at the remote stations as the user would expect if he where the sole operator of a private computer.
- A system of charging based upon a flat service charge and a variable charge based on usage.
- Capacity for indefinite growth, so that as the customer load increases, the system can expanded without limit by various means.
In addition to the general-purpose public form, there are countless other possible shapes that a computer utility might take. This include private general-purpose systems, public special purpose systems, public and private multi-purpose systems and a whole heirarchy of increasingly complex general-purpose public systems extending all the way to national systems.
As generally envisaged, a computer public utility would be a general purpose public system, simultaneously making available to a multitude of diverse geographically distributed users a wide range of different information processing services and capabilities on an on-line basis.
The public / private division is reflected in our experience with older utilities, communication, gas, electric power etc. In fact, historically, many of our present public utilities began as limited subscriber or private ventures. Even today, despite the fantastic growth of public systems, many organizations continue to operate their own private power plants or internal communication systems.
It is necessary to consider each application of computer utility separately on its merits and balance off in each case the gains and losses resulting from the adoption of the utility concept.
A number of importance considerations tend to improve the cost/effectiveness picture.
- Reduced solution time for engineering and scientific problems.
- A capability for an organisation to provide faster service to its customers.
- Reduce user capital equipment and facility investments.
- Better utilization of computer resources
Extracts from Douglas Parkhill, The challenge of the computer utility, 1966. (thanks to Tom Wasserman for pointing me in this direction)