Devices

OS/2 enables you to access peripheral devices using file system commands, and treat those devices as file streams of data. These devices include:

Character devices

COM, clock, console (keyboard and screen), screen, keyboard, printer, null, pointer, and mouse devices.
Standard I/O devices
Character devices automatically installed by OS/2 and recognized by the file system as the standard input, standard output, and standard error devices.
Pseudocharacter devices
An application can attach a device name to a file system and use the file system as a pseudocharacter device (also called a single-file device). Attaching a device name to a file system allows an application to open the device associated with the file system as if it were a character device (for example, a serial port) and read from and write to the device by using DosRead and DosWrite.

In addition, an application can use DosSetFilePtr and DosSetFileLocks with a pseudocharacter device. Also, pseudocharacter devices can be redirected.

A file system that can be attached to a pseudocharacter device is typically associated with a single disk file or with a special storage device, such as a tape drive. The file system establishes a connection with the device and transfers requests and data between OS/2 and the device. The user perceives this file as a device name for a nonexistent device.

This file is seen as a character device because the current drive and directory have no effect on the name. A pseudocharacter device name is an ASCII string with the name of an OS/2 file in the form:

  \DEV\DEV_NAME

The "\dev\" is a required part of the name, but there is no actual subdirectory named "\dev\". This just lets OS/2 know that it is a pseudocharacter device name.

Logical file devices
The hard disk or floppy disk drives, or the partitions on the hard disk or floppy disk drives.

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