IBM 9020

The IBM 9020 refers to IBM System/360-family computers adapted into a multiprocessor system for use by the U.S. FAA for en route Air Traffic Control in its 20 Air Route Traffic Control Centers beginning in the late 1960s. The IBM 9020A, for example, was based on the System 360/50 and the 9020D used 2 out of 3 360/65 processors for flight and radar data processing with 2 out of 3 360/50 processors providing input/output capability.

The 9020As and 9020Ds were in service until 1989 when they were finally replaced by IBM 3083 BX1 mainframes as part of the FAA's HOST upgrade. The 3083s in turn were replaced with IBM 9672 RA4 parallel processing servers during the FAA's Host and Oceanic Computer System Replacement (HOCSR) completed in 1999. At least during the first phase of the upgrade, the 9672's were running the FAA's original assembly language code in System/360 emulation mode. Because of the failure of the FAA's Advanced Automation System (AAS) project, the 9020E display control systems lasted well into the 1990s.

One reason for the 1999 upgrade was concern, probably unfounded, that the IBM 3083's microcode would not operate properly in the year 2000.

ources

*http://www.thegalleryofoldiron.com/9020E.HTM
* [http://domino.research.ibm.com/tchjr/journalindex.nsf/9fe6a820aae67ad785256547004d8af0/720f85f2446ebfc485256bfa00685a26?OpenDocument An application-oriented multiprocessing system, Part II: Design characteristics of the 9020 system]
* [http://findarticles.com/p/articles/mi_m0ISJ/is_n4_v29/ai_9680873 Re-engineering software: a case study - air traffic control software - technical]