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Files Reference

/etc/locks Directory


Contains lock files that prevent multiple uses of communications devices and multiple calls to remote systems.


The /etc/locks directory contains files that lock communications devices and remote systems so that another user cannot access them when they are already in use. Other programs check the /etc/locks directory for lock files before attempting to use a particular device or call a specific system.

A lock file is a file placed in the /etc/locks directory when a program uses a communications device or contacts a remote system. The file contains the process ID number (PID) of the process that creates it.

The Basic Networking Utilities (BNU) program and other communications programs create a device lock file whenever a connection to a remote system, established over the specified device, is actually in use. The full path name of a device lock file is:


where the DeviceName extension is the name of a device, such as tty3.

When the BNU uucico daemon, cu command, or tip command places a call to a remote system, it puts a system lock file in the /etc/locks directory. The full path name of a system lock file is:


where the SystemName extension is the name of a remote system, such as hera. The system lock file prevents more than one connection at a time to the same remote system.

Under normal circumstances, the communications software automatically removes the lock file when the user or program ends the connection to a remote system. However, if a process executing on the specified device or system does not complete its run (for example, if the computer crashes), the lock file remains in the /etc/locks directory either until the file is removed manually or until the system is restarted after a shutdown.

Implementation Specifics

This directory is part of Base Operating System (BOS) Runtime.

Related Information

The connect subcommand for the ATE command, ct command, cu command, pdelay command, pshare command, slattach command, tip command.

The uucico daemon.

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