Capability-based addressing

<p>In <a href="/facts/Computer_science/lN3pEyPz">computer science</a>, capability-based addressing is a scheme used by some computers to control access to memory as an efficient implementation of <a href="/facts/Capability-based_security/negzSwhS">capability-based security</a>. Under a capability-based addressing scheme, <a href="/facts/Pointer_(computer_programming)/fPoNzy9b">pointers</a> are replaced by protected objects (named capabilities) which specify both a location in memory, along with access rights which define the set of operations which can be carried out on the memory location. Capabilities can only be created or modified through the use of <a href="/facts/Privilege_(computer_science)/7eS1wna4">privileged</a> instructions which may be executed only by either the <a href="/facts/Kernel_(computer_science)/uEj4U3Rz">kernel</a> or some other privileged process authorised to do so. Thus, a kernel can limit application code and other subsystems access to the minimum necessary portions of memory (and disable write access where appropriate), without the need to use separate <a href="/facts/Address_space/EscyYKkP">address spaces</a> and therefore require a <a href="/facts/Context_switch/N0oJQ6CC">context switch</a> when an access occurs.
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Capability-based addressing open-in-new

Capability-based addressing