Model 204 relies on its own type ofbitmap index, originally devised by Bill Mann, and combines the use ofhash table,B-tree, and partitioned record list technologies to optimize speed and efficiency of database access.[4][5]
It has been described as "one of the three major inverted-list [databasesystems] ... the other two being"ADABAS and ADR's Datacom/DB.[6]
Although M204 is a pre-SQL (and pre-relational) database product, it is possible to manually map the files of an M204 database to approximate SQL equivalents and provide some limited SQL functionality using Model 204 SQL Server.[7]
Model 204 has been a central part of Australian social security for decades.Services Australia have used it for their ISIS system that pays over $110 billion in welfare payments to around 6 million Australians.[15] A 1.5 billion Australian dollar project to replace ISIS was expected to be completed in 2022 but was delayed.[16][17][18] The project was scrapped in July 2023 having spentAUD 191 million, since the replacement system (based onPegasystems business process automation software) took minutes to complete tasks Model 204 could complete in seconds.[19]
In a 2014 media interview, then Treasurer of AustraliaJoe Hockey stated that the Australian social security system and the Pentagon were the only remaining active Model 204 customers in the world.[20]
Add-on products for Model 204 database were formerly available from Sirius Software, Inc.[21]Sirius, located in Cambridge, Massachusetts, USA, was acquired by Rocket Software in 2012.[22]
^"with Model 204 you get excellent performance, even with large databases and ... of America's largest companies— for financial applications, inventory control.""Model 204 database".ComputerWorld. December 1980. p. 36.
^O'Neil, Patrick (1987)."Model 204 Architecture and Performance".Proceedings of the 2nd International Workshop on High Performance Transaction Systems. Springer-Verlag. pp. 40–59.
^"Software AG memories". March 25, 2011.ADABAS was .. one of the three major inverted-list DBMS, the other two being Computer Corporation of America's Model 204 and ADR'sDATACOM/DB.
^"Model 204 is commonly used in government and military applications. Among other things,it runs Australia's social security system.""What is Model 204?". December 17, 2013.
