Gerald A. Marazas

A high-level performance analysis of the IBM subsystem control block (SCB) architecture

Abstract With the use of new intelligent adapters, advanced bus architectures, and powerful microprocessors, the latest personal computers need a new architecture to coordinate the transfers of command and control information, data, and status between their system components in the most efficient manner. To this end, IBM has defined the Subsystem Control Block (SCB) architecture. In this paper, we would like to present our modeling approach to analyze the operational and performance characteristics of this architecture and its two operating modes, the Locate Mode and the Move Mode. The models, which were implemented using the IBM Research Queueing Package (RESQ), are described, and the results obtained from the models are presented. The analysis of these results demonstrates the capability of the SCB architecture to handle large amounts of data in a LAN-server environment, and the superiority of the Move Mode over the Locate Mode as defined in the architecture.

A Multi-Stage Decision Approach to Prioritized Automatic Acquisition

The automatic acquisition of radar targets is the major aspect of the IBM Maritime Applications/Bridge System discussed in this paper. The Collision Assessment module searches an operator specified portion of the radar field. Targets of interest are acquired and placed in a priority tracking structure according to the degree of threat they pose. The Collision Assessment module solves the problem of false targets arising from sea clutter and surrounding land masses by screening out false targets in a unique fashion involving a high degree of software control. Results drawn from experience with an automatic acquisition installation on an English Channel ferry are discussed. A logical extension is to offshore platforms, particularly those located adjacent to principal access routes to ports.