| MTBF-Calculation acc. to Standards
Siemens SN 29500
has been developed by former RAC, now RiAC, who owned the Mil-HDBK-217 standard
in the past. 217Plus is the successor of PRISM and was released in 2006.
The name 217Plus was chosen for marketing purposes in order to replace Mil-HDBK-217, which was already quite dated at that time. However this strategy has terribly failed.
Today, 217Plus is only rarely used.