These are separate modeling approaches. MIL-HDBK-217F, Notice 2 is a US DoD handbook that was last updated in 1995 (Notice 2 revision). 217Plus, developed in 2005, is a more comprehensive state-of-the-art modeling approached that was developed under the Reliability Information Analysis Center contract (a DoD contract). MIL-HDBK-217 covers only electronics. 217Plus covers electronics with models that are similar to MIL-HDBK-217, but more robust in that they include non-operating periods and more specific factors for thermal cycling. 217Plus also covers other areas such as mechanical items, by providing an interface (software version only) to the RIAC non-electronic parts reliability database (NPRD-95) and the RIAC electronics parts reliability database (EPRD-97). 217Plus also provides a software reliability prediction methodology and a benchmarking procedure to assess more intangible factors such as a companies design and manufacturing practices.
