The main feature of random access memory is that it can read or write data at any time, but the stored data will disappear once the power supply is interrupted. It is mainly used to temporarily store programs and data.RAM can be divided intoDynamic memory(Dynamic RAM, DRAM) andStatic memory(Static RAM, SRAM).DRAM has high storage density and low cost, but it needs to be updated with circuit, and the speed is slow.SRAM is fast, but has low storage density and high cost.Common computerMain memoryThe capacity refers to the capacity of DRAM installationCPUThe cache memory between the main memory and the SRAM uses the SRAM with fast connectivity, but the cost is high, so the capacity is not large.
Chinese name
Random access memory
Foreign name
random access memory
Disadvantages
Volatility
Features
Very sensitive to the static charge of the environment
The so-called "random access" means that whenstorageWhen a message in is read or written, the time required is independent of the location of the message.In contrast, when reading or writing information in a Sequential Access storage device, the time required is related to the location (such as tape).
Volatility
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RAM cannot retain data when the power is turned off.If you need to save data, you must write them
In a long-term storage device (such as a hard disk).The biggest difference between RAM and ROM is that the data saved on RAM will disappear automatically after power failure, while the ROM will not.
High access speed
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contemporaryRandom access memoryThe speed of writing and reading is the fastest among almost all access devices. Compared with other storage devices involving mechanical operation, the memory retrieval delay is also insignificant.
Refresh required
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contemporaryRandom access memoryDepends on capacitors to store data.When the capacitor is fully charged, it represents 1 (binary), and when it is not charged, it represents 0.Since the capacitor has more or less leakage, if no special treatment is made, the data will gradually lose over time.Refresh refers to reading the state of the capacitor regularly, and then recharging the capacitor according to the original state to make up for the lost charge.Need to refresh Just explainedRandom access memoryVolatility.
Sensitive to static electricity
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Like other fine integrated circuits,Random access memoryIt is very sensitive to the electrostatic charge of the environment.Static electricity will interferestorageThe charge of the internal capacitor causes data loss and even burns the circuit.So touchRandom access memoryBefore, touch the metal grounding with hands.
