The Cheyenne Mountain Upgrade (CMU) of November 1988, designed to consolidate five improvement programs, was not installed because it was not compatible with other systems at Cheyenne Mountain and it did not meet the defined specifications according to deficiencies identified during testing. The five improvement programs were the CCPDS Replacement (CCPDS-R), CSS Replacement (CSS-R), Granite Sentry upgrade, SCIS, and SPADOC 4. SPADOC 4 was for upgrading the SCC with primary and backup 3090-200J mainframes), and SPADOC 4 block A achieved initial operating capability (IOC) in April 1989. The CSS-R "first element" achieved IOC on April 12, 1991; and the 427M system was replaced . The CSSR, SCIS, Granite Sentry, CCPDS-R, and their interfaces were tested in 1997. Testing of Granite Sentry nuclear detonation (NUDET) data processing system found it to be inadequate.