osf1 man page for locks

locks(4)						     Kernel Interfaces Manual							  locks(4)

NAME
       locks  -  A  directory that contains lock files for communication devices and remote systems that prevent multiple attempts to use the same
       device or contact a remote system

SYNOPSIS
       /var/spool/locks

DESCRIPTION
       Lock files are created by the uucico daemon, the cu command, the tip command, and the uugetty command in  the  /var/spool/locks	directory.
       The files are created when the utility opens the serial line for communication.

       The lock file locks the device or remote system so that another process cannot access it while it is in use. The file name of the lock file
       uses one of the following forms: LCK..device_name LCK..system_name Where device_name is the name of the device (such  as  ttyd0)  and  sys-
       tem_name is the name of the system (such as hera).

       Normally,  the  process	that  creates a lock file will remove it when the process has finished using the line. However, it is possible for
       lock files to be left behind (for example: system crash, phone line disconnects unexpectedly). This situation has been  accounted  for  and
       the commands that use lock files can handle the situation and overwrite these files, if appropriate.

       Lock  files contains the process ID (PID) of the process that created the lock.	The lock file is a data file; to see its contents, use the
       following command:
	od -d lockfile

       Where lockfile is the name of the file. For example: % od -d /var/spool/locks/LCK..ttyd0 0000000  06854 00000 0000004

       In this example, the lock file (LCK..ttyd0) was created by the process with PID 6854.

FILES
       Contains the uucico daemon and uugetty program.	Contains the uucp, cu, and tip programs.

RELATED INFORMATION
       Commands: cu(1), od(1), tip(1), uucp(1), uugetty(8)

       Daemons: uucico(8) delim off

																	  locks(4)