Synchronous Dynamic Random-access Memory

Synchronous Dynamic Random-access Memory

Synchronous dynamic random access memory (SDRAM) is dynamic random access memory (DRAM) that is synchronized with the system bus. Classic DRAM has an asynchronous interface, which means that it responds as quickly as possible to changes in control inputs. SDRAM has a synchronous interface, meaning that it waits for a clock signal before responding to control inputs and is therefore synchronized with the computer's system bus. The clock is used to drive an internal finite state machine that pipelines incoming commands. The data storage area is divided into several banks, allowing the chip to work on several memory access commands at a time, interleaved among the separate banks. This allows higher data access rates than an asynchronous DRAM.

Pipelining means that the chip can accept a new command before it has finished processing the previous one. In a pipelined write, the write command can be immediately followed by another command, without waiting for the data to be written to the memory array. In a pipelined read, the requested data appears after a fixed number of clock cycles after the read command (latency), clock cycles during which additional commands can be sent. (This delay is called the latency and is an important performance parameter to consider when purchasing SDRAM for a computer.)

SDRAM is widely used in computers; from the original SDRAM, further generations of DDR (or DDR1) and then DDR2 and DDR3 have entered the mass market, with DDR4 currently being designed and anticipated to be available in 2013.

Read more about Synchronous Dynamic Random-access Memory:  SDRAM History, SDRAM Timing, SDR SDRAM, Failed Successors

Famous quotes containing the words dynamic and/or memory:

    Magic is the envelopment and coercion of the objective world by the ego; it is a dynamic subjectivism. Religion is the coercion of the ego by gods and spirits who are objectively conceived beings in control of nature and man.
    Richard Chase (b. 1914)

    It is not however, adulthood itself, but parenthood that forms the glass shroud of memory. For there is an interesting quirk in the memory of women. At 30, women see their adolescence quite clearly. At 30 a woman’s adolescence remains a facet fitting into her current self.... At 40, however, memories of adolescence are blurred. Women of this age look much more to their earlier childhood for memories of themselves and of their mothers. This links up to her typical parenting phase.
    Terri Apter (20th century)