GRANDPRÉ: Description cannot suit itself in words To demonstrate the life of such a battle In life so lifeless as it shows itself.
|--The Life of Henry the Fifth, IV, ii, 53–55.|
A protection system describes the conditions under which a system is secure. In this chapter, we present a classical formulation of a protection system. The access control matrix model arose both in operating systems research and in database research; it describes allowed accesses using a matrix.
The state of a system is the collection of the current values of all memory locations, all secondary storage, and all registers and other components of the system. The subset of this collection that deals with protection is the ...