BNU lock files

The BNU lock files are stored in the /var/locks directory. When BNU uses a device to connect to a remote computer, it places a lock file for that device in the /var/locks directory.

When another BNU program or any other program needs the device, that program checks the /var/locks directory for a lock file. If a lock file exists, the program waits until the device is available or uses another device for the communication.

In addition, the uucico daemon places lock files for remote systems in the /var/locks directory. Before contacting a remote system, the uucico daemon checks the /var/locks directory for a lock file for that system. These files prevent other instances of the uucico daemon from establishing duplicate connections to the same remote system.