Protocols for intelligent terminals

Abstract

For some time now most people associated with research computer networks have championed the concept of layered protocols. These are uniform rules of procedure that are intended to be obeyed by each of the different computer systems, connected by a network, in order to disguise their differences and so allow them to intercommunicate freely with each other. The concept is an attractive one and has now been taken up in various standards bodies with a view to agreeing standards for 'open networking' through the public data networks. In principle, if a suitable set of standards can be agreed, any computer system will be able to call any other one and interact with it to conduct a variety of transactions. however, the extent to which this will be true in practice has yet to be established. The layered protocol approach has proved very effective at the lower levels, but could become cumbersome if it is pushed too far. If this happens, and clumsy standards emerge, large software packages will be required to implement them in each of the cooperating computers. Such packages will be more complex than is desirable for many of the simpler applications, and will add unnecessarily to operational overheads in the smaller systems. This note suggests an alternative approach that seems worthy of consideration in the light of recent advances in micro-electronics and the likely requirements of future systems. In particular, for intelligent terminals with only one user active there will be less need for the multi-threaded protocols of today, but a greater emphasis must be given to simplicity, so that implementation and subsequent maintenance will be easy and cheap. Accordingly, free-form protocols are introduced, and advocated as a means of harnessing the intelligence of terminals together with the intelligence of their users to greater effect than has hitherto been common.