ram is running memory. The full English name of ram is Random Access Memory, which means random access memory; ram is also an internal memory that directly exchanges data with the CPU; RAM can be read and written at any time, and it is very fast. It is usually used as Temporary data storage medium for operating systems or other running programs.
The operating environment of this article: Windows 7 system, Dell G3 computer.
Running memory, also called main memory, refers to the memory required when the program is running. It can only temporarily store data and is used to exchange cache data with the CPU. It generally refers to random access memory (Random Access Memory, RAM).
Random access memory
A memory in which data can be written and read quickly in random order to a memory cell at any location in the storage array. It is the place where the computer saves the operating system, applications and user data. Unlike the hard disk or other storage devices, it allows the processor to obtain data more quickly, but all data stored in RAM will be lost after shutting down. When the user turns it on again, the computer will automatically load the operating system and other files (usually from the hard disk) into RAM again. RAM is similar to human short-term memory, and hard disk is similar to human long-term memory. Short-term memory is specific to the current job and can store a lot of data at the same time. Long-term memory can be refreshed as needed by short-term memory. It has the following characteristics:
Random access
The so-called "random access" refers to the required The time has nothing to do with the location of this piece of information. In contrast, there are serial access memories including sequential access memories (such as tapes) and direct access memories (such as disks).
Volatile
RAM cannot retain data when the power is turned off. If data needs to be saved, they must be written to a long-term storage device (such as a hard drive). 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.
Higher access speed
Modern random access memory has the fastest writing and reading speeds among almost all access devices, and the access latency is also the same as other Compared with storage devices involving mechanical operations (such as hard drives and optical disk drives), they are also insignificant. But the speed is still not as good as SRAM used as CPU cache.
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 the capacitor has leakage to some extent, if no special treatment is taken, the charge will gradually drain over time, causing data errors. Refreshing means recharging the capacitor to make up for the lost charge. Reading DRAM has the function of refreshing, but general scheduled refresh does not require a complete read. You only need to select a column (Row) of the chip, and the data of the entire column can be refreshed. At the same time, All related memory chips can select the same column at the same time. Therefore, all memories can be refreshed by refreshing all columns one by one within a period of time. The need to refresh explains exactly the volatile nature of random access memory.
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.
RAM can be divided into two categories: main memory, which is used to save data needed by various processors, which can speed up the computer's operation; video memory, which is used to save data to be displayed on the monitor. Graphical information can be displayed much faster. Main memory can be divided into two types: SRAM and DRAM. SRAM is a relatively expensive memory, and it occupies a relatively large physical space and is difficult to integrate. However, because it does not need to be refreshed, the access speed is fast. SRAM is usually used for level one cache and level two cache. Because DRAM uses capacitors, its contents must be refreshed at certain intervals, otherwise the internal data will be lost. For DRAM, every read is actually a discharge, and the capacitor must be charged to ensure the validity of its content. Even if it is not read, it needs to be refreshed every 15 milliseconds. Its The price is the cheapest among RAM.
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