TABLE OF CONTENTS Forty years ago or even thirty performance engineering was a very different area from what it is now. For a start, it was then termed teletraffic ; more significantly, the range of systems and problems studied was much narrower, the variety much less, and the speed of evolution incomparably lower.
It was also focused, to a degree which is difficult to understand from today's perspective. Problems were thoroughly indeed exhaustively studied, irrespective of the wider context, until the definitive answer was obtained. Massive simulations of entire switching systems were run and re-run until it was identified whether their capacity at some essentially arbitrary performance level was 2000E or 2001E; and the community of telecommunications engineers, if not that of teletraffic engineers, believed that it mattered.
Only with the opening-up of the business following privatisation and liberalisation in the 1980s did this attitude begin to alter. Within the UK, a seachange was effected by the so-called overall grade-of-service studies carried out within BT, which made evident for the first time the extent of variability of performance figures over a properly managed network (including how very far the typical system was from its notional design-date target!). Differences which were previously seen as significant, albeit not important, were suddenly placed in context; and the definitive study was never the same again.
That performance engineers, unlike ammonites, still survive in what is a very different world is due to two factors the importance of the...
