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- config VT
- bool "Virtual terminal" if EXPERT
- depends on !S390
- select INPUT
- default y
- ---help---
- If you say Y here, you will get support for terminal devices with
- display and keyboard devices. These are called "virtual" because you
- can run several virtual terminals (also called virtual consoles) on
- one physical terminal. This is rather useful, for example one
- virtual terminal can collect system messages and warnings, another
- one can be used for a text-mode user session, and a third could run
- an X session, all in parallel. Switching between virtual terminals
- is done with certain key combinations, usually Alt-<function key>.
- The setterm command ("man setterm") can be used to change the
- properties (such as colors or beeping) of a virtual terminal. The
- man page console_codes(4) ("man console_codes") contains the special
- character sequences that can be used to change those properties
- directly. The fonts used on virtual terminals can be changed with
- the setfont ("man setfont") command and the key bindings are defined
- with the loadkeys ("man loadkeys") command.
- You need at least one virtual terminal device in order to make use
- of your keyboard and monitor. Therefore, only people configuring an
- embedded system would want to say N here in order to save some
- memory; the only way to log into such a system is then via a serial
- or network connection.
- If unsure, say Y, or else you won't be able to do much with your new
- shiny Linux system :-)
- config CONSOLE_TRANSLATIONS
- depends on VT
- default y
- bool "Enable character translations in console" if EXPERT
- ---help---
- This enables support for font mapping and Unicode translation
- on virtual consoles.
- config VT_CONSOLE
- bool "Support for console on virtual terminal" if EXPERT
- depends on VT
- default y
- ---help---
- The system console is the device which receives all kernel messages
- and warnings and which allows logins in single user mode. If you
- answer Y here, a virtual terminal (the device used to interact with
- a physical terminal) can be used as system console. This is the most
- common mode of operations, so you should say Y here unless you want
- the kernel messages be output only to a serial port (in which case
- you should say Y to "Console on serial port", below).
- If you do say Y here, by default the currently visible virtual
- terminal (/dev/tty0) will be used as system console. You can change
- that with a kernel command line option such as "console=tty3" which
- would use the third virtual terminal as system console. (Try "man
- bootparam" or see the documentation of your boot loader (lilo or
- loadlin) about how to pass options to the kernel at boot time.)
- If unsure, say Y.
- config HW_CONSOLE
- bool
- depends on VT && !S390 && !UML
- default y
- config VT_HW_CONSOLE_BINDING
- bool "Support for binding and unbinding console drivers"
- depends on HW_CONSOLE
- default n
- ---help---
- The virtual terminal is the device that interacts with the physical
- terminal through console drivers. On these systems, at least one
- console driver is loaded. In other configurations, additional console
- drivers may be enabled, such as the framebuffer console. If more than
- 1 console driver is enabled, setting this to 'y' will allow you to
- select the console driver that will serve as the backend for the
- virtual terminals.
- See <file:Documentation/console/console.txt> for more
- information. For framebuffer console users, please refer to
- <file:Documentation/fb/fbcon.txt>.
- config UNIX98_PTYS
- bool "Unix98 PTY support" if EXPERT
- default y
- ---help---
- A pseudo terminal (PTY) is a software device consisting of two
- halves: a master and a slave. The slave device behaves identical to
- a physical terminal; the master device is used by a process to
- read data from and write data to the slave, thereby emulating a
- terminal. Typical programs for the master side are telnet servers
- and xterms.
- Linux has traditionally used the BSD-like names /dev/ptyxx for
- masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
- has a number of problems. The GNU C library glibc 2.1 and later,
- however, supports the Unix98 naming standard: in order to acquire a
- pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
- terminal is then made available to the process and the pseudo
- terminal slave can be accessed as /dev/pts/<number>. What was
- traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
- All modern Linux systems use the Unix98 ptys. Say Y unless
- you're on an embedded system and want to conserve memory.
- config DEVPTS_MULTIPLE_INSTANCES
- bool "Support multiple instances of devpts"
- depends on UNIX98_PTYS
- default n
- ---help---
- Enable support for multiple instances of devpts filesystem.
- If you want to have isolated PTY namespaces (eg: in containers),
- say Y here. Otherwise, say N. If enabled, each mount of devpts
- filesystem with the '-o newinstance' option will create an
- independent PTY namespace.
- config LEGACY_PTYS
- bool "Legacy (BSD) PTY support"
- default y
- ---help---
- A pseudo terminal (PTY) is a software device consisting of two
- halves: a master and a slave. The slave device behaves identical to
- a physical terminal; the master device is used by a process to
- read data from and write data to the slave, thereby emulating a
- terminal. Typical programs for the master side are telnet servers
- and xterms.
- Linux has traditionally used the BSD-like names /dev/ptyxx
- for masters and /dev/ttyxx for slaves of pseudo
- terminals. This scheme has a number of problems, including
- security. This option enables these legacy devices; on most
- systems, it is safe to say N.
- config LEGACY_PTY_COUNT
- int "Maximum number of legacy PTY in use"
- depends on LEGACY_PTYS
- range 0 256
- default "256"
- ---help---
- The maximum number of legacy PTYs that can be used at any one time.
- The default is 256, and should be more than enough. Embedded
- systems may want to reduce this to save memory.
- When not in use, each legacy PTY occupies 12 bytes on 32-bit
- architectures and 24 bytes on 64-bit architectures.
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