Random Access Memory (English: Random Access Memory, abbreviation: RAM), also called main memory, is an internal memory that directly exchanges data with the CPU. It can be read and written at any time (except when refreshing, see below), is fast, and is often used as a temporary data storage medium for the operating system or other running programs.
Characteristics of ram:
1. Random access
The so-called "random access" refers to the When data in memory is read or written, the time required has nothing to do with the location of the information. In contrast, when reading or writing information in a sequential access (Sequential Access) storage device, the time and location required are related (such as tape).
2. Volatility
RAM cannot retain data when the power is turned off. If data need to be saved, they must be written to static random access memory in a long-term storage device (such as a hard disk). Compared with RAM and ROM, the biggest difference between the two is that the data stored in RAM will disappear automatically after the power is turned off, while ROM will not.
3. High access speed
Modern random access memory has the fastest writing and reading speeds among almost all access devices, and the access delay is also the same as other storage involving mechanical operations. The equipment is insignificant compared to it.
4. Need to refresh
Modern random access memory relies on capacitors to store data. A fully charged capacitor represents a 1 (binary), and an uncharged capacitor represents a 0. Since capacitors have leakage to some extent, data will gradually be lost over time if no special treatment is taken. Refreshing means periodically reading the status of the capacitor and then recharging the capacitor according to its original status to make up for the lost charge. The need to refresh explains exactly the volatile nature of random access memory.
5. Sensitive to static electricity
Like other delicate integrated circuits, random access memory is very sensitive to electrostatic charges in the environment. Static electricity can interfere with the charge of the capacitors in the memory, causing data loss or even burning out the circuit. Therefore, before touching the random access memory, you should first touch the metal ground with your hand.
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