Hierarchical Analysis of Computer Memory

The common feature of all storage devices that belong to the storage management scope of the operating system is that after the system loses power, the information stored in them will be lost, and they are volatile storage devices. Storage devices that belong to the management scope of the operating system settings can permanently save the stored information, and they are non-volatile storage devices.

The main memory is used to store programs and data required for program operation. A computer system must have a large enough main memory. Its capacity is one of the indicators to measure the performance of a computer system. Since the access speed of the main memory is much lower than that of the register, in order to speed up the access speed, the computer system often configures a cache between the main memory and the register to store the program modules and data currently used by the processor.

As for disk cache, it itself is not an actual storage medium. It relies on fixed disks and is mainly used to provide expansion of main memory.

Registers are physically located on the same chip as the processor's computing control part. They are closest to the computing part and have the highest access speed, but their capacity is not very large. Therefore, they are mainly used to temporarily store some intermediate data or special data for control, and cannot store large amounts of data such as programs.