Tested systems are often described as "free from known error" in recognition that complex systems cannot be proven to be error free.
In IT Operations known errors may be logged in a system's Known Error Database (KEDB) which is then used to prioritize changes and to develop customer support reference information where a work around exists.
- Foundations of IT Service Management: Based on ITIL, Van Haren Publishing, 2005, p. 57, ISBN 978-90-77212-58-5
- Partridge, Derek (1992), Engineering artificial intelligence software, Intellect Books, p. 45, ISBN 978-1-871516-06-7
- Van Bon, Jan; Pieper, Mike (2008), Service Strategy Based on ITIL V3: A Management Guide, Van Haren Publishing, p. 135, ISBN 978-90-8753-124-9