A lockdown is an emergency protocol to prevent people or information escaping, which usually can only be ordered by someone in command. They are also used to protect people inside a facility from a dangerous external event: schools practice lockdowns in the wake of Columbine High School shootings in which students with guns enter the school; or from an internal event: prison facilities also practice lockdown procedure on their inmates when faced with rioting or unrest.
A partial lockdown means that the doors leading outside of the building are locked and people may not exit or enter the building. A full lockdown means that people must stay where they are and may not exit or enter a classroom, apartment unit, store unit, an office space, condo unit or to enter or exit the building. If people are in a hallway they must go into the nearest classroom, apartment unit, condo unit, office space or store unit. The term 'lockdown' can be defined as an emergency course of action taken by an agent of authority, such as police or prison personnel, to contain a problem or incident within the area of its origin by controlling the movement of people.
Confining prisoners to their cells to prevent a riot from spreading to other parts of a prison is a good example of a 'lockdown'.
Under their new powers, the New South Wales Police Service 'locked down' targeted areas and roads at Cronulla, Bondi, Coogee, Maroubra and Brighton-le-Sands to prevent persons of middle eastern appearance from committing reprisal attacks and prevent white supremacist agitators from further violence.
In the wake of the September 11th attacks a three day lockdown of American airspace was initiated to prevent any remaining perpetrators from escaping. Similarly in the case of the 7th July Bombings where London was locked down. In this case it was also a precaution to cut off any further attacks.
An example of a campus/school lockdown was demonstrated at the University of British Columbia on January 30, 2008 where an unknown threat was made and the Royal Canadian Mounted Police (RCMP) issued a lockdown on one of the buildings on campus for 6 hours, cordoning off the area and a campus alert was sent via email to everyone who is affiliated with UBC while students and faculties were to remain locked in the building.
On April 10, 2008 two Canadian secondary schools were locked down due to suspected gun threats. George S. Henry Academy was locked down in Toronto, Ontario at approximately 2:00p.m.. The Emergency Task Force (TPS) were contacted and the lockdown lasted for more than two hours. New Westminster Secondary School was locked down in New Westminster, British Colombia at approximately 1:40 p.m.. The Emergency Response Team (ERT) were called and the school was under lockdown until 4:30 p.m. Due to the size of the school, some students were not able to leave until 7:00 p.m.
A digital lockdown is to prevent all outward flow of information on a computer, including internet access, and internal applications. It is used to prevent the spread of viral infections, and glitches in the computer, or to keep a computer hijacker from stealing information.