Model 204
Encyclopedia
Model 204 is a Database management system
for IBM and compatible mainframes
, which was first deployed in 1972. It incorporates a programming language and an environment for application development. It can deal with very large database
s and very high transaction loads.
Model 204 relies on its own type of bitmap index
, originally devised by Professor Patrick E. O'Neil, and also combines the use of hash table
, B-tree
, and record list technologies to optimize speed and efficiency of database access.
Model 204 is most commonly used in government and military applications. Among other things, it runs Australia's social security system (Centrelink
). It is used commercially in the UK by Marks & Spencer
. It is also used at the Ventura County Property Tax system in California, and in the New York City Department of Education
's Automate The Schools
system.
It is a product of Computer Corporation of America (CCA). In April 2010, CCA was acquired by Rocket Software, a Boston-based developer of Enterprise Infrastructure products.
Add-on products are available from Sirius Software, Inc.
Database Programmer's Toolkit
is a freeware PC-based emulation.
Database management system
A database management system is a software package with computer programs that control the creation, maintenance, and use of a database. It allows organizations to conveniently develop databases for various applications by database administrators and other specialists. A database is an integrated...
for IBM and compatible mainframes
IBM mainframe
IBM mainframes are large computer systems produced by IBM from 1952 to the present. During the 1960s and 1970s, the term mainframe computer was almost synonymous with IBM products due to their marketshare...
, which was first deployed in 1972. It incorporates a programming language and an environment for application development. It can deal with very large database
Very large database
A very large database, or VLDB, is a database that contains an extremely high number of tuples , or occupies an extremely large physical filesystem storage space. The most common definition of VLDB is a database that occupies more than 1 terabyte or contains several billion rows, although naturally...
s and very high transaction loads.
Model 204 relies on its own type of bitmap index
Bitmap Index
A bitmap index is a special kind of database index that uses bitmaps.Bitmap indexes have traditionally been considered to work well for data such as gender, which has a small number of distinct values, for example male and female, but many occurrences of those values. This would happen if, for...
, originally devised by Professor Patrick E. O'Neil, and also combines the use of hash table
Hash table
In computer science, a hash table or hash map is a data structure that uses a hash function to map identifying values, known as keys , to their associated values . Thus, a hash table implements an associative array...
, B-tree
B-tree
In computer science, a B-tree is a tree data structure that keeps data sorted and allows searches, sequential access, insertions, and deletions in logarithmic time. The B-tree is a generalization of a binary search tree in that a node can have more than two children...
, and record list technologies to optimize speed and efficiency of database access.
Model 204 is most commonly used in government and military applications. Among other things, it runs Australia's social security system (Centrelink
Centrelink
Centrelink is the trading name of the Commonwealth Service Delivery Agency , a statutory authority responsible for delivering human services on behalf of agencies of the Commonwealth Government of Australia. The majority of Centrelink's services are the disbursement of social security payments...
). It is used commercially in the UK by Marks & Spencer
Marks & Spencer
Marks and Spencer plc is a British retailer headquartered in the City of Westminster, London, with over 700 stores in the United Kingdom and over 300 stores spread across more than 40 countries. It specialises in the selling of clothing and luxury food products...
. It is also used at the Ventura County Property Tax system in California, and in the New York City Department of Education
New York City Department of Education
The New York City Department of Education is the branch of municipal government in New York City that manages the city's public school system. It is the largest school system in the United States, with over 1.1 million students taught in more than 1,700 separate schools...
's Automate The Schools
Automate The Schools
Automate The Schools is the school-based administrative system used by all New York City public schools since 1988. It has many functions, including recording biographical data for all students, handling admissions, discharges, and transfers to other schools, and recording other student-specific...
system.
It is a product of Computer Corporation of America (CCA). In April 2010, CCA was acquired by Rocket Software, a Boston-based developer of Enterprise Infrastructure products.
Add-on products are available from Sirius Software, Inc.
Database Programmer's Toolkit
Database Programmer's Toolkit
Database Programmer's Toolkit is a freeware product which emulates CCA's Model 204 DBMS.DPT was created by Richard Groves in September 2004 as a basic Model 204 emulator where User Language code could be executed without the need for a mainframe...
is a freeware PC-based emulation.