The Computers: Software: Operating Systems: (Capability Operating Systems )

Capability, or capability-based, operating systems (OSs) are those which use, and are often structured via, capabilities (in some systems called a key), for security. Many OSs, such as Unix types, or later versions of Microsoft Windows, use privileges for security. Privileges apply to users, and are course-grained. Capabilities are somewhat similar, but apply to objects within the software environment, and are fine-grained. A capability is a communicable, unforgeable token of authority. It refers to a value that references an object, along with an associated set of access rights. User programs on capability OSs must use a capability to access an object; they are designed to directly share capabilities with each other according to the principle of least privilege, and with the OS infrastructure needed to make such transactions efficient and secure. Capability Operating Systems Software Computers.