The program controls listed prescreen or edit data prior to processing, but the sequence check is most likely to be used only in batch processing. A sequence -heck lets to determine that records are in proper order. For example, a payroll input file can be sorted into Social Security number order. A sequence check can then be performed to verify record order. This control would not apply in a real-time operation be :-,use records are not processed sequentially.

Access should be limited to those whose activities necessitate access to the computer
system. Moreover, the degree of access allowed should be consistent with an individual's responsibilities. Restricting access to particular individuals rather than groups or departments clearly establishes specific accountability. Not everyone in a group will need access or the same degree of access. Thus, passwords assigned to individuals should be required for identification of users by the system. Furthermore, data should be restricted at the field level, not the workstation level. It may be possible to limit access to a workstation, but most workstations are connects -d t. larger mainframe or network databases. Thus, the security at the workstation level only would be insufficient.

Queuing (waiting-line) models minimize, for a given rate of arrivals, the sum of (1) the cost of providing service (including facility costs and operating costs) and (2) the cost of idle resources waiting in line. The latter may be a direct cost, if paid employees are waiting, or an opportunity cost in the case of waiting customers. This minimization occurs at the point where the cost of waiting is balanced by the cost of providing service.