Software patching in the SPC environment and its impact on switching system reliability

The author highlights various concepts related to software patching in the stored program control (SPC) environment. He introduces the concept of software maintenance and studies the effect of the software patching process on switching system reliability. The importance of managing the software change process, including patch testing and patch tracking, is discussed. The types of patches that are typically applied in the SPC switching environment are described. It is pointed out that the prime objective of real-time software suppliers, especially those supporting SPC switching systems, should be to minimize online patching. It is concluded that proper design specification of SPC switching functions and patches, coupled with exhaustive testing of software/hardware interfaces, could help reduce the number of patches in the field