In a drum storage unit a shortest-latency-time-first (SLTF) file drum is used to read or write records on files while the drum is rotating. Once a decision is made to process a particular record, the...

In a drum storage unit a shortest-latency-time-first (SLTF) file drum is used to read or write records on files while the drum is rotating. Once a decision is made to process a particular record, the time spent waiting for the record to come under the read/write heads which are fixed is called the latency. The records are not constrained to be of any particular strength. Also, no restrictions are placed on the starting position of the records. Assume that the circumference of the drum is the unit of length and the drum rotates at a constant angular velocity, with period t (Fuller (1980)). Suppose a queueing model is to be used to analyze the performance of the drum-storage unit described above. Describe the elements of such a system and the characteristics to be considered for its performance evaluation.