The head0 user-space virtual terminal

One user-space virtual terminal is supplied as a pre-packaged suite of connected service bundles:

• a suite of ttylogin@vcN service bundles providing TUI login services

• a suite of terminal-emulator@vcN service bundles running console-terminal-emulator to provide terminal emulation to the TUI login sessions and presenting themselves as /run/dev/vcN

• a console-multiplexor@head0 service bundle running console-multiplexor to multiplex among the lower vcN terminals and presenting itself as /run/dev/head0mux

• a console-input-method@head0 service bundle running console-input-method to layer an input method on top of the multiplexor and presenting itself as /run/dev/head0

• a console-fb-realizer@head0 service bundle running console-fb-realizer to realize the overall combination at /run/dev/head0 onto some I/O devices

Configuration

The console-multiplexor@head0 service bundle expects to find symbolic links matching the shell wildcard vc[0-9]* in its service directory, pointing to the virtual terminals that it is multiplexing amongst. Reconfiguring what terminals are multiplexed is therefore a matter of adding, removing, or changing a symbolic link in that link farm and restarting the multiplexor service, which can be done on the fly without affecting the applications running in the TUI login sessions.

The console-input-method@head0 service bundle is configured with several environment variables:

lower

the name of the virtual terminal supplied by console-multiplexor@head0, which is initially configured as /run/dev/head0mux

chinese1

the optional name of the CIN file to use for the 1st Hanzi/Kanji/Hanja conversion mode

chinese2

the optional name of the CIN file to use for the 2nd Hanzi/Kanji/Hanja conversion mode

kana

the optional names of the two CIN files to use for the Hiragana and Katakana conversion modes

hangeul

the optional names of the CIN file to use for the Hangeul conversion mode

romaji

the optional names of the CIN file to use for the Romaji conversion mode

The console-fb-realizer@head0 service bundle is configured with several environment variables:

KERNEL_VT

the number (Linux) or device file name (BSDs) of the old-style kernel virtual terminal that is used for I/O device sharing

OWNED_DEVICES

the optional names of devices that the user-vt-realizer group is granted rw access to at service startup and restart

DETACHED_UGEN_DEVICES

the optional names of devices, that are expected to be generic USB (a.k.a. ugen) devices, that the kernel HID device drivers are told to detach from at service startup and restart

FONTS

the optional command-line options and arguments specifying font files to load

INPUTS

the optional command-line options and arguments specifying HIDs to use

KBDMAP

the optional name of the keyboard map file to load

FRAMEBUFFER

the names of the framebuffer device file to use (Linux only)