
6.3 Requirements Analysis 151
The last group of requirements addresses issues such as reliability, perform-
ance, security, and adaptability. This category serves as a catchall group and
acts as a prompter for all the nonfunctional requirements that are important
to the software project. In large transaction-oriented applications, it is imper-
ative that a performance requirement on transaction rate be specified. In life-
threatening applications, the reliability and the availability parameters must
be defined in the requirement statements. Availability addresses the system
being up, and reliability addresses the issue of it functioning properly w