bsd man page for lock

LOCK(2) 							System Calls Manual							   LOCK(2)

NAME
       lock - lock a process in primary memory (2BSD)

SYNOPSIS
       lock(flag)
       int flag

DESCRIPTION
       If  the	flag  argument is non-zero, the process executing this call will not be swapped unless it is required to grow.	If the argument is
       zero, the process is unlocked.  This call may only be executed by the super-user.

ERRORS
       [EPERM]	      The caller is not the super-user.

BUGS
       Locked processes interfere with the compaction of primary memory and can cause deadlock.  This system call is not  considered  a  permanent
       part of the system.

       Lock is unique to the PDP-11 and 2BSD; its use is discouraged.

3rd Berkeley Distribution					 January 22, 1987							   LOCK(2)