Devices and Files

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.

The discussion of I/O files is divided into two sections:

• Logical Devices, which describes logical unit specifiers, external files, and internal files.
• Files, which describes the types of files, file access, record types, and Microsoft Fortran PowerStation compatible files.