the memory usually refers to the RAM in the computer system. RAM requires constant power supply at all times, otherwise data will be lost.
it would be nice if the data in the RAM is not lost after the power is turned off, so that the computer can be kept in the last shutdown state every time it is turned on, instead of restarting the computer and reopening the application program every time. But RAM requires constant power supply. Is there any way to solve this problem? With the development of technology, people have thought of a way to supply a small amount of power to RAM to keep the data of RAM from being lost. This is the hibernation function of computers, especially in Win2, when the power supply is connected, it consumes a small amount of electricity.
according to the interface form of memory banks, there are two common memory banks: single in-line memory banks (SIMM) and dual in-line memory banks (DIMM). SIMM memory chips are divided into 3 lines and 72 lines. Compared with SIMM memory stick, DIMM memory stick has 168 pins. DIMMs can be used singly, different capacities can be mixed, and SIMM must be used in pairs.
according to the working mode of the memory, the memory has the forms of fpedo dRAM and SDRAM (synchronous dynamic ram).
FPA(FAST PAGE MODE)RAM fast page mode random access memory: this is the memory commonly used in earlier computer systems, and it transmits data every three clock cycles.
EDO(EXTENDED DATA OUT)RAM extended data output random access memory: EDO memory cancels the time interval between two storage cycles of the motherboard and the memory, and outputs data every two clock cycles, which greatly shortens the access time and improves the storage speed by 3%. EDO is generally 72 pins, and the memory of EDO has been replaced by SDRAM.
S(SYSNECRONOUS)DRAM synchronous dynamic random access memory: SDRAM has 168 pins, which is the memory currently used by PENTIUM and above models. SDRAM locks CPU and RAM together through the same clock, so that CPU and RAM can share a clock cycle and work synchronously at the same speed, and the rising edge of each clock pulse begins to transfer data, which is 5% faster than that of EDO memory.
DDR (double data rage) RAM: an updated product of SDRAM, which allows data to be transmitted at the rising and falling edges of clock pulses, so that the speed of SDRAM can be doubled without increasing the clock frequency.
RDRAM(RAMBUS DRAM) memory bus dynamic random access memory; RDRAM is a new type of DRAM developed by RAMBUS company with system bandwidth and chip-to-chip interface design. It can transmit data through a simple bus in a very high frequency range. At the same time, he uses low-voltage signals to transmit data at both edges of high-speed synchronous clock pulses. INTEL will add support for RDRAM to its 82 chipset products.
there are two main parameters of memory: storage capacity and access time. The larger the storage capacity, the more information the computer can remember. The access time is calculated in nanoseconds (NS). One nanosecond equals 1 9 seconds. The smaller the number, the faster the memory access speed.