Memory bank

A memory bank is a logical unit of storage in electronics, which is hardware dependent. In a computer the memory bank may be determined by the memory access controller along with physical organization of the hardware memory slots. In a typical synchronous dynamic random-access memory (SDRAM) or double data rate synchronous dynamic random-access memory (DDR SDRAM), a bank consists of multiple rows and columns of storage units and is usually spread out across several chips. In a single read or write operation, only one bank is accessed, therefore bits in a column or a row, per bank, per chip = memory bus width in bits (single channel). The size of a bank is further determined by bits in a column and a row, per chip× number of chips in a bank.

Some computers have several identical memory banks of RAM, and use bank switching to switch between them. Harvard architecture computers have (at least) 2 very different banks of memory, one for program storage and one for data storage.

In caching

Memory bank is a part of (cache) memory that is addressed consecutively in the total set of memory banks, i.e., when data item a(n) is stored in bank b, data item a(n + 1) is stored in bank b + 1. (Cache) memory is divided in banks to evade the effects of the bank cycle time (see above). When data is stored or retrieved consecutively each bank has enough time to recover before the next request for that bank arrives.^[1]

The number of memory modules needed to have the same number of data bits as the bus. A bank can consist of one or more memory modules.

See also

• Computer memory
• Bank switching
• Memory organisation
• Interleaved memory
• Memory Geometry

References