File types

 

The file management functions support these types of files.

• Database files are files (including distributed files) whose associated data is stored permanently in the system.

• Device files are files that provide access to externally attached devices such as displays, printers, tapes, diskettes, and other systems that are attached by a communications line. The device files supported are:

  • Display files, which provide access to display devices

  • Printer files, which describe the format of printed output

  • Tape files, which allow access to data files on tape devices

  • Diskette files, which provide access to data files on diskette devices

  • Intersystem communications function files (ICF files), which allow a program on one system to communicate with a program on the same system or another system.

• Save files are files that are used to store saved data on disk (without requiring diskettes or tapes).

• Distributed data management (DDM) files are files that allow access to data files stored on remote systems.

Each file type has its own set of unique characteristics that determines how the file can be used and what capabilities it can provide. The concept of a file, however, is the same regardless of what type of file it is. When a file is used by a program, it is referred to by name, which identifies both the file description and, for some file types, the data itself. This information is designed to help you understand the common characteristics of all file types so you can use the files to their full capabilities.

 

Parent topic:

Overview of database file management

 

Related concepts

Copying files
Opened files
Limitation of access to files and data when creating files
Shared files
Application of overrides