Physical security involves the prevention of physical damage to system
hardware, and prevention of the corruption of software.
The causes of damage to hardware and software can range from deliberate
sabotage or vandalism, to inadvertent damage caused by unskilled users.
Physical access to hardware is usually effected by perimeter controls, which restrict entry into areas in which computer equipment is located.
Access to software is usually controlled by logon restrictions. Such
restrictions include the use of passwords, establishment of accounts and
groups, and control of user capabilities. Access to programs and files can be provided by assigning users to accounts, issuing appropriate capabilities, using passwords, lockwords, and creating programs and files in groups that belong to special accounts. The physical aspect of securing access to software involves prevention of physical access to terminals, and limitations on or prevention of access via communication lines.
