console(HW)

console -- console terminal devices

Description

A console terminal is a terminal used to display kernel message and other system status messages, or to interact with basic system services, such as init(ADM). The physical system console is the console terminal used by the kernel and selected by the boot(F) CONSOLE parameter; must be a console-capable device, as indicated by the C flag in the characteristics field of the last line in the device driver's Master(DSP) file; the Master file should also have a K flag in the characteristics field.

/dev/console - the physical system console

The file /dev/console is the physical system console. Programmers should write console messages to /dev/console.

/dev/console is selected by the boot(F) CONSOLE parameter. If no CONSOLE parameter is set, the first console-capable device is used.

/dev/syscon - the virtual system console

The file /dev/syscon is the virtual system console; that is, it ``floats'' to whatever device was last used to change system states. Usually /dev/console and /dev/syscon are identical. init(ADM) uses /dev/syscon to prompt for system state changes and for other interactions.

/dev/sysmsg - the direct console driver

The file /dev/sysmsg is a node for the sysmsg pseudo-device driver. This driver sends I/O to the physical system console via console I/O entry points, rather than the STREAMS interfaces. /dev/sysmsg is used during the sysinit phase of init since the console may not yet have been fully initialized, and since init can not remake the /dev/console node until the root file system becomes writeable).

Files

   /dev/console
   /dev/syscon
   /dev/sysmsg

References

boot(F), init(ADM), inittab(F), Master(DSP)