Defining Reliability

In the same manner that Associate Justice Potter Stewart of the U.S. Supreme Court struggled to define pornography in 1964 (“…but I know it when I see it.”), many IT professionals and users know unreliability when they see it, watching in frustration as their PC crashes, hangs, or runs slower than usual, or when applications stop working as expected. But defining reliability is a harder problem.

Definitions vary: Consumers may simply say their computer is reliable when it works the way they expect it to, and works when they want to use it. IT managers may define a computer as reliable when it runs predictably, runs a wide variety of applications without stumbling, and delivers application services properly, while requiring minimal maintenance or interruption. Developers may consider a computer reliable when it allows them to develop software that will function as specified.

Industrywide consensus and cooperation in defining reliability is important to Microsoft, because the total reliability of a system can be impacted by hardware and non-Microsoft software.