The Unisys Data Management System II (DMSII)
is a database system
originally created by the Burroughs Corporation
in 1972. It was available on the Burroughs (later Unisys
) Small (B1000), Medium (4000, V Series) and Large System (5000, 6000, 7000) product lines. The later, A Series, Clearpath, Libra product lines support it and in recent releases of Unisys Clearpath
software it has been renamed as the Enterprise Database Server for ClearPath MCP
It originally competed with IBM's IMS
products and predated the popularity of relational databases.
DMSII provided: an ISAM
model for data access, transaction isolation and database recovery capabilities.
The database schema
was written in the proprietary Data and Structure Definition Language (DASDL). The DASDL source code was compiled with a system utility into a file containing the meta-data for the database, known as the Description file. A database utility program would use the database Description file to create the remaining components of the database.
Proprietary language compilers (such as COBOL
) would use the database Description file to create database related elements in the object code of the compiled program. These compilers used language extensions to provide a more natural interface to the database by the programmer. A number of intrinsic functions were inserted by the compiler to ensure the program and database were using the same definition of database... Read More