DCONS(4FREEBSD) - Linux man page online | Special files

Dumb console device driver.

January 26, 2008
DCONS(4) BSD Kernel Interfaces Manual DCONS(4)


dcons — dumb console device driver


To compile this driver into the kernel, place the following lines in your kernel configura‐ tion file: options GDB device firewire device dcons Alternatively, to load the driver as a module at boot time, place the following line in your kernel configuration file: options GDB and in loader.conf(5): dcons_load="YES"


The dcons device is a simple console device which just reads from and writes to an allocated buffer for input and output respectively. It is of no use by itself and it is supposed that the buffer is accessed via a bus like firewire(4) or kvm(3) for interaction. The buffer consists of 4 channels. There are 2 ports, one for the console TTY and another is GDB port, then each port has an input channel and an output channel.


/dev/dcons /etc/ttys


If you want to run getty(8) on dcons, insert the following line into ttys(5) and send a HUP signal to init(8) using kill(1). dcons "/usr/libexec/getty std.9600" vt100 on secure Once the fwohci(4) device is initialized to allow physical access, the buffer can be accessed from another host via a firewire(4) bus using the dconschat(8) application. See dconschat(8) for more details. If you want to use dcons as a gdb(1) port, add the following line into loader.conf(5): dcons_gdb="1"


dcons_crom(4), ddb(4), firewire(4), fwohci(4), gdb(4), ttys(5), conscontrol(8), dconschat(8), fwcontrol(8)


Hidetoshi Shimokawa <>


This driver is currently under development.
BSD January 26, 2008 BSD
This manual Reference Other manuals
dcons(4freebsd) referred by dcons_crom(4freebsd) | firewire(4freebsd) | gdb(4freebsd) | ieee1394(4freebsd)
refer to agetty(8) | dcons_crom(4freebsd) | ddb(4freebsd) | firewire(4freebsd) | fwohci(4freebsd) | gdb(1) | gdb(4freebsd) | kill(1)
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