Patent ID: 6990437

Claim:
Apparatus for designing an optimal information system architecture of a business entity, comprising: a model generator for producing one or more models representing the business entity's IS architecture needs at different levels of abstraction, at least one model representing an IS architecture meeting desired performance criteria of the business entity; and an optimizer coupled to receive the at least one model and evaluate, in a numerical manner, implementations of the corresponding IS architecture such that an optimal IS architecture is determined, the optimizer modeling memory performance by determining a probability of accessing desired pages of page sets in an active zone memory, wherein the active zone memory includes a portion of rarely referenced pages, determining a probability of accessing the desired pages in the active zone memory comprises: for each page set, determining a probability of any page being present in the active zone memory; for each page set, determining a number of distinct pages accessed; for each page set, determining a number of pages present in the active zone memory from the number of distinct pages accessed and the probability of any page being present in the active zone memory; and determining a hit ratio as the number of pages present in the active zone memory relative to the total number of page accesses.