The Eschenbach drum scheme
Allen Weingarten · Communications of the ACM · 1966
The prime function of a drum, operating in real time, is to perform accesses quickly.The usual means for increasing this capacity is to incorporate engineering or hardware improvements.In this paper the problem is attacked not by changing the drum, but rather by modifying the manner in which it operates.At the outset, a drum is given a functional definition.Then a simple design scheme (Eschenbach) is introduced which enormously increases the rate of accessing for drums so defined.This is shown to enable a system to perform a job by employing fewer or less expensive drums.It is suggested that although the design scheme has a specific use, the method underlying it has more general applicability.The question of the efficacy of the drum scheme is then raised.To deal with this, a standard of efficiency is developed in light of realistic real-time circumstances.The drum scheme is then modelled in a manner which permits it to be analyzed as a problem in queueing theory.Thus one is enabled to ascertain whether the drum scheme is efficient enough for its application.Again, whereas the analysis of the drum scheme has a specific use, the methods underlying it have mote general applicability.