Content-addressable storage
（重定向自Content addressed storage）
Content-addressable storage, also referred to as associative storage or abbreviated CAS, is a mechanism for storing information that can be retrieved based on its content, not its storage location. It is typically used for high-speed storage and retrieval of fixed content, such as documents stored for compliance with government regulations. Roughly speaking, content-addressable storage is the permanent-storage analogue to content-addressable memory.