Linux special devices

In general,

Block devices: are devices that store or hold data

Character devices: can be thought of as devices that transmit or transfer data.

For example, diskette drives, hard drives and CD-ROM drives are all Block devices while serial ports, mice and parallel printer ports are all character devices.

/Dev/ttys0 (first communications port, COM1)

First serial port (mice, modems ).

/Dev/psaux (PS/2)

PS/2 mouse connection (mice, keyboards ).

/Dev/lp0 (first printer port, LPT1)

First parallel port (printers, scanners, etc ).

/Dev/DSP (first audio device)

The name DSP comes from the term digital signal processor, a specialized processor chip optimized for Digital Signal Analysis. sound cards may use a dedicated DSP chip, or may implement the functions with a number of discrete
Devices. Other terms that may be used for this device are digitized voice and PCM.

/Dev/USB (USB devices)

This subdirectory contains most of the USB device nodes. device name allocations are fairly simplistic so no elaboration is be necessary.

/Dev/SDA (C: \, SCSI device)

First SCSI device (HDD, memory sticks, external mass storage devices such as CD-ROM drives on laptops, etc ).

/Dev/SCD (D: \, SCSI CD-ROM device)

First SCSI CD-ROM device.

/Dev/js0 (Standard gameport joystick)

First joystick device.

Devices are defined by type, such as 'block' or 'character ', and 'major' and 'minor' number. the major number is used to categorize a device and the minor number is used to identify
A specific device type.