Files serve as the connecting link between a program and the device used
for I/O. Each file on the system has an associated file description which
describes the file characteristics and how the data associated with the file
is organized into records and fields.
In order for a program to perform any I/O operations, it must identify
the file description(s) the program is referencing, what type of I/O device
is being used, and how the data is organized. This chapter provides general
information on:
- Associating file descriptions with input/output devices
- Defining externally described files
- Defining program-described files
- Data management operations
Information on how to use externally and program-described files with
different device types is found in subsequent chapters.