blogd(8) [suse man page]

BLOGD(8)						       The SuSE boot concept							  BLOGD(8)

NAME

       blogd - boot logging on /dev/console

SYNOPSIS

       /sbin/blogd [/dev/realtty]

DESCRIPTION

       Without	argument blogd determines the real underlying character device of /dev/console.  blogd spawns a pty/tty pair to reconnect the cur-
       rent /dev/console with the slave of the pty/tty pair. During writing information from this slave to the real character device a ring buffer
       is used to hold the information for writing it to an existing logging file.

       To  fetch  the  real  tty  of /dev/console the program showconsole(8) can be used. This has the advantage that blogd will not hold the real
       character device of /dev/console as its controlling tty (would hangup any running getty on that character device).

SIGNALS

       blogd knows a few signal to contol its behavior.

       SIGQUIT, SIGINT, and SIGTERM
	      will cause blogd tries to write out the ring buffer and to exit.

       SIGIO  says blogd that now it is able to write on /var/log/boot.msg which means that the file system is mounted read/write and  the  kernel
	      messages are written to that file.

       SIGSYS says blogd that it should stop writing to disk but continue to repeat messages to the old devices of the system console.

BUGS

       blogd  needs  a	mounted  /proc	and  /dev/pts  file  system  and tries to set the controlling tty to stdin if the real character device of
       /dev/console is not given.  After reading /proc blogd tries to restore the status of the controlling tty to avoid problems with getty  pro-
       cesses.	This can fail because blogd forks to run in the background as a daemon.

FILES

       /proc/<pid of blogd>/stat
	      the stat file of the blogd process.

       /dev/console
	      the system console.

       /var/log/boot.msg
	      logging file which is created by klogd(8) or dmesg(8).

SEE ALSO

       showconsole(8), syslogd(8), klogd(8), dmesg(8), proc(5).

COPYRIGHT

       2000 Werner Fink, 2000 SuSE GmbH Nuernberg, Germany.

AUTHOR

       Werner Fink <werner@suse.de>

3rd Berkeley Distribution					   Nov 10, 2000 							  BLOGD(8)

CONSOLE(4)						     Linux Programmer's Manual							CONSOLE(4)

NAME

       console - console terminal and virtual consoles

DESCRIPTION

       A  Linux  system  has  up to 63 virtual consoles (character devices with major number 4 and minor number 1 to 63), usually called /dev/ttyn
       with 1 <= n <= 63.  The current console is also addressed by /dev/console or /dev/tty0, the character device with major number 4 and  minor
       number  0.   The  device  files	/dev/*	are  usually created using the script MAKEDEV, or using mknod(1), usually with mode 0622 and owner
       root.tty.

       Before kernel version 1.1.54 the number of virtual consoles was compiled into the kernel (in tty.h: #define NR_CONSOLES	8)  and  could	be
       changed by editing and recompiling.  Since version 1.1.54 virtual consoles are created on the fly, as soon as they are needed.

       Common ways to start a process on a console are: (a) tell init(1) (in inittab(5)) to start a mingetty(8) (or agetty(8)) on the console; (b)
       ask openvt(1) to start a process on the console; (c) start X--it will find the first unused console, and display its output there.   (There
       is also the ancient doshell(8).)

       Common  ways  to  switch consoles are: (a) use Alt+Fn or Ctrl+Alt+Fn to switch to console n; AltGr+Fn might bring you to console n+12 [here
       Alt and AltGr refer to the left and right Alt keys, respectively]; (b) use Alt+RightArrow or Alt+LeftArrow to cycle through  the  presently
       allocated  consoles; (c) use the program chvt(1).  (The key mapping is user settable, see loadkeys(1); the above mentioned key combinations
       are according to the default settings.)

       The command deallocvt(1) (formerly disalloc) will free the memory taken by the screen buffers for consoles that no longer have any  associ-
       ated process.

   Properties
       Consoles  carry a lot of state.	I hope to document that some other time.  The most important fact is that the consoles simulate vt100 ter-
       minals.	In particular, a console is reset to the initial state by printing the two characters ESC c.  All escape sequences can be found in
       console_codes(4).

FILES

       /dev/console
       /dev/tty*

SEE ALSO

       chvt(1),  deallocvt(1),	init(1),  loadkeys(1),	mknod(1),  openvt(1),  console_codes(4),  console_ioctl(4),  tty(4), ttyS(4), charsets(7),
       agetty(8), mapscrn(8), mingetty(8), resizecons(8), setfont(8)

Linux								    1994-10-31								CONSOLE(4)