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utility programs and subroutines to the Sigma 7 computer system and then later, in 1982, updating to an IBM/VM/370 mainframe computer system.
7.2.2 Classification of the Petrodata System Certain procedures are required to operate the Petrodata system for a particular territory. They comprise three sequential subsystems: maintenance, retrieval, and application. Fig. 7.1 is a flow diagram of the Petrodata system.
Fig. 7.1 Flow diagram – petrodata system
7 The Petrodata DataBase System
7.2.2.1 The Maintenance Subsystem The maintenance subsystem is an essential primary step to input, validate, and update data until a severity code is accepted and stored in the database (DB); all data in the database are indexed by the database index feature that is available on the maintenance subsystem whenever the database is accessed. The maintenance subsystem is the capstone source of the petrodata system, because it is responsible for storing geographical, geological, geophysical, and production well data for each specific petroleum field. It establishes a complete record of these data, which should be processed through a validation program that