# Fortran I/O

In Fortran's I/O system, data is stored and transferred among files. All I/O data sources and destinations are considered files.

Devices such as the screen, keyboard, and printer are external files, as are data files stored on a device such as a disk.

Variables in memory can also act as a file on a disk and are typically used to convert ASCII representations of numbers to binary form. When variables are used in this way, they are called internal files.

For more information, see the individual topics in this section.

Parent topic: Data and I/O

- Logical Devices
- Physical Devices (Windows*)
- Types of I/O Statements
- Forms of I/O Statements
- Assign Files to Logical Units
- File Organization
- Internal Files and Scratch Files
- File Access and File Structure
- File Records
- Record Types
- Record Length
- Record Access
- Record Transfer
- Specify Default Pathnames and File Names
- Open Files: OPEN Statement
- Obtain File Information: INQUIRE Statement
- Close Files: CLOSE Statement
- Record I/O Statement Specifiers
- File Sharing (Linux* and macOS)
- Specify the Initial Record Position
- Record I/O: Advancing and Nonadvancing
- User-Supplied OPEN Procedures: USEROPEN Specifier
- Microsoft Fortran PowerStation Compatible Files (Windows*)
- Use Asynchronous I/O