The Legac-e Information Site

Stages of File Processing

File, or Data Set, processing requires a number of actions which are listed opposite.

These actions are consistent with those performed by other programming languages such as; Assembler, COBOL and PLI.

Each of the fives stages will be explored in more detail shortly, but before that it is worth exploring how EXECIO uses menory.

Actions required to process a file.

1. Allocate the file
   
   This assigns the file or data set to the User or Task.
   
   
2. Open the file
   
   This makes the file or data set available for processing.
   
   
3. Perform the Input / Output Operations
   
   This is the execution of the READ and / or WRITE instructions.
   
   
4. Close the file,
   
   Ensures residual data in buffers is written to the file.
   
   
5. De-allocate the file
   
   Free the file for other Users.