The /dev directory belongs to the process manager and contains device files.
The files that this directory includes may include:
- /dev/cdn
- CD-ROM block devices; see
devb-*
in the Utilities Reference for driver information.
- /dev/conn
- Text mode console TTY device; see
devc-con
in the Utilities Reference.
- /dev/console
- The device that's used for diagnostic log messages; on a full x86 system, this
is a write-only device managed by the system logger,
slogger.
Buildfiles for embedded systems may configure a link from this path to
another device, such as a serial port. See slogger in the
Utilities Reference.
- /dev/fdn
- Floppy disk block devices; see
devb-fdc
in the Utilities Reference for driver details.
- /dev/hdn
- Hard disk block devices; data representing an entire drive, spanning all partitions; see
devb-*
in the Utilities Reference.
- /dev/hdntn
- Hard disk partition block devices; the data in these devices is a subset of that
represented by the corresponding hdn file; see
devb-*
in the Utilities Reference.
- /dev/io-net/
- A directory owned and operated by
io-pkt*,
under which you can find files relating to the network devices for your
various LANs. C programs can perform
devctl()
operations on these files to interact with the driver, e.g., to obtain driver statistics.
Note:
Only legacy io-net drivers create entries under
/dev/io-net/; native io-pkt* drivers don't.
- /dev/mem
- A device that represents all physical memory.
- /dev/mq, /dev/mqueue
- A pathname space where entries for message queues appear; for more information, see
mq and mqueue
in the Utilities Reference.
- /dev/null
- A "bit bucket" that you can direct data to. The data is discarded.
- /dev/parn
- Parallel ports e.g., for parallel printers; see
stty
for configuration, and
devc-par
for driver details in the Utilities Reference.
- /dev/pci
- Adopted by the PCI server on the machine, this device lets programs communicate
with the PCI server. See
pci-*
in the Utilities Reference.
- /dev/pipe
- Adopted by the
pipe
manager. The presence of this file tells other programs (such as a
startup script built into an OS image) that the Pipe manager is successfully running.
- /dev/pty[p-zP-T][0-9a-f]
- The control side of a pseudo-terminal device pair. Pseudo-ttys are named with a
letter (p–z or P–T) followed by a hexadecimal digit, making it
possible to have up to 256 devices. See
devc-pty
in the Utilities Reference.
- /dev/random
- Read from this device to obtain random data; see
random
in the Utilities Reference.
- /dev/sem
- A pathname space where entries for named semaphores appear.
- /dev/sern
- Serial ports. See
stty
for configuration, and
devc-ser*
for driver details in the Utilities Reference.
- /dev/shmem/
- Contains files representing shared memory regions on the system (also sometimes
used for generic memory-mapped files). For more information, see the description of the
RAM "filesystem"
in Working with Filesystems.
- /dev/slog
- A device managed by
slogger,
used to read or write system log messages.
Try sloginfo /dev/slog. See slogger and
sloginfo
in the Utilities Reference for more information.
- /dev/socket/
- This directory is owned and managed through the TCP/IP stack, which is included in
io-pkt*.
This directory contains pathnames through which applications interact with the stack.
For more information, see the
TCP/IP Networking chapter in this guide.
- /dev/text
- This file is managed by
procnto.
Text written to this device is output through debug output routines
encoded in the startup code for your system.
The actual result, therefore, varies from board to board. On a standard PC
(using startup-BIOS), the default is to write to the PC console.
For more information, see
startup-*
in the Utilities Reference.
- /dev/tty
- A virtual device owned by the process manager
(procnto)
that resolves to the controlling terminal device associated with the
session of any process that opens the file. This is useful for programs that may
have closed their standard input, standard output, or standard error, and later
wish to write to the terminal device.
- /dev/tty[p-zP-T][0-9a-f]
- The slave side of the corresponding
/dev/pty[p-zP-T][0-9a-f] file.
The program being controlled typically uses one of these files for its standard input,
standard output, and standard error.
- /dev/zero
- Supplies an endless stream of bytes having a value of zero.