Device file&dev naming conventions

1. Character devices
2. Block devices
3. Pseudo-devices
• /dev/null
• Accepts and discards all input; produces no output.
• /dev/zero
• Accepts and discards all input; produces a continuous stream of NULL (zero value) bytes.

• /dev/full
• Produces a continuous stream of NULL (zero value) bytes when read, and returns a "disk full" message when written to.
• /dev/random and /dev/urandom
• Produces a variable-length stream of truly random or pseudo-random numbers.

Linux naming conventions

The following prefixes have come into common use in Linux-based systems, to identify the type of a device driver interface in the /dev hierarchy:

• fb: frame buffer
• fd: (platform) floppy disks, though this same abbreviation is also commonly used to refer to file descriptor
• hd: (“classic”) IDE driver (previously used for ATA hard disk drive, ATAPI optical disc drives, etc.)
  • hda: the master device on the first ATA channel (usually identified by major number 3 and minor number 0)
  • hdb: the slave device on the first ATA channel
  • hdc: the master device on the second ATA channel
    • hdc1: first partition on this disk (example)
    • hdc5: first logical drive in the extended partition (example)
  • hdd: the slave device on the second ATA channel
• lp: line printers (compare lp)
• parport, pp: parallel ports
• pt: pseudo-terminals (virtual terminals)
• SCSI driver, also used by libATA (modern PATA/SATA driver), USB, IEEE 1394, etc.
  • sd: mass-storage driver
    • sda: first registered device
      • sda4: last partition on this disk (example)
      • sda6: second logical drive in the extended partition (example)
  • ses: Enclosure driver
  • sg: generic SCSI layer
  • sr: “ROM” driver (data-oriented optical disc drives; scd is just a secondary alias)
  • st: magnetic tape driver
• tty: terminals
  • ttyS: (platform) serial port driver
  • ttyUSB: USB serial converters, modems, etc.