Associative memory essays

Associative memory essays Most memory devices store and retrieve data by addressing specific memory locations. As a result, this path often becomes the limiting factor for systems that rely on fast memory access. The time required to find an item stored in memory can be reduced considerably if the stored data item can be identified for access by the content of the data itself rather than by its address. Memory that is accessed in this way is called content-addressable memory (CAM) or associative memory. CAM provides a performance advantage over other memory search algorithms (such as binary and tree-based searches or look-aside tag buffers) by comparing the desired information against the entire list of prestored entries simultaneously, often resulting in an order-of-magnitude reduction of search time. CAMs are an outgrowth of RAM which is an integrated circuit that stores data temporarily. Data is stored in RAM at a particular location, which is called an address. In RAM, the user supplies the address and gets the data back. The number of address lines limits the depth of a memory using RAM, but the width of the memory can be extended as far as desired. With CAM, the user supplies the data and gets the address back. The CAM searches through the memory in one-clock cycle and returns the address where the data is found. The CAM can be preloaded at device startup and rewritten during device operation. CAM can accelerate any application requiring fast searches of databases, lists, or patterns, such as in image or voice recognition, or computer and communication designs. For this reason, CAM is used in applications where search time is critical and must be very short. For example, the search key could be the IP address of a network user, and the associated information could be a users access privileges and location on the network. If the search key presented to the CAM is present in the CAMs table, the CAM indicates a match and returns the associa...