The Cambridge Distributed Computing System

It is well known that the dramatic developments of the last few years in integrated circuit technology have revolutionised the approach taken to the provision of computer hardware. The use of many microcomputers with substantial amounts of memory is considered routine,and it is quite reasonable to use machines for a single function only. The exploitation of this possibility in the cause of simplicity has been made much easier by another development, perhaps less well known,in communication technology. It is now possible to interconnect computers in a building or a cluster of buildings by means of a local area network. Such networks typically carry data at rates from a megabit per second upwards with very high reliability. Both in terms of speed and of reliability, they may be contrasted with earlier systems using telephone lines. In traditional networks much effort had to be devoted to protocols that made the best use possible of the limited bandwidth and that were as rugged as possible against the effects of transmission error. Connection equipment tended to be expensive, and accordingly there was good reason to minimise the number of systems connected. The modern local network is capable of being interfaced much more cheaply and of being used with much simpler protocols.