Fashionable OK Words by Maurice Wilkes


So, 60 years ago, started an article in Electronics Weekly’s edition of January 18th 1961 written by the computer pioneer Sir Maurice Wilkes who led the creation in Cambridge of the 1949 EDSAC – one of the world’s first stored programme computers.

The article continues:

The interest aroused by this subject is indicated by the fact that a conference devoted specifically to it was organised recently in Delft by the Benelux branch of the Institute Of Radio Engineers.

Data transmission is in principle as old as telegraphy itself. The new interest is a result of the coming of computers, and the computers have brought with them a new insistence on speed and accuracy.

It is in these respects that the systems now being introduced represent an advance on existing telegraph practice.

The oldest-and still the most accurate form of data transmission is the ordinary postal service.

A number of firms have made use of this – or of equivalent means such as passenger train- to convey information to a central computer for processing,and to convey the results to their destination.

There is an insurance company with a data-processing installation at its headquarters in Canada which is linked to the London office by air-mail.

Where the post is fast enough, there is everything to be said for using it. However, in many circumstances the mismatch beween the speed of a digital computer and that of the postal service is too great, and too little time is left for the sorting out of difficulties.

We all use the postal service for the conduct of our ordinary business, but we pick up the telephone as soon as anything goes wrong.

If the quantity of data to be transmitted is not too great, a teleprinter channel capable of transmitting about 50 bits per second is quite fast enough, and a number of organisations have used such circuits with encouraging results.

The fact that no automatic check on the accuracy of transmission is provided is, however,a great disadvantage.

Telegraph and computer engineers are now working on systems in which redundant information is added to each block of information before it is transmitted, so that a check of consistency can be made at the distant end.

If this check reveals no error, the block of information is accepted; otherwise a signal is sent to the transmitting end and the block is retransmitted.

A few systems of this type are already in use. Most of the present effort is going into systems which use ordinary. telephone lines and transmit information at about 1,000 bits per second.





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