What types of internal memory can be divided into?

Internal memory can be divided into 2 categories: 1. Read-only memory (ROM), which works in a non-destructive readout mode. It can only read information but not write it. Once the information is written, it is fixed. Even if the power is cut off, the information will not be lost; 2. Random access memory (RAM) is an internal memory that directly exchanges data with the CPU. It can be read and written at any time (except when refreshing), and it is very fast. It is usually used as an operating system or other operating system. Temporary data storage medium for running programs.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

Internal memory, referred to as memory, is one of the important components of the computer. It is used to temporarily store calculation data in the CPU and exchange data with external memories such as hard disks. It is the bridge between external memory and the CPU. All programs in the computer run in the memory. The performance of the memory affects the overall performance of the computer. As long as the computer starts running, the operating system will transfer the data that needs to be calculated from the memory to the CPU for calculation. When the calculation is completed, the CPU will transmit the results.

The central processing unit (CPU) can only directly access the data stored in the memory, while the data in the external memory can only be accessed and processed by the central processing unit after being transferred into the memory.

The internal memory is directly connected to the CPU. It has a small storage capacity but is fast. It is used to store the instructions and data of the currently running program and exchange information directly with the CPU. The internal memory is composed of many storage units, each unit can store a binary number or an instruction represented by a binary code. Internal memory is composed of random access memory and read-only memory.

Read-Only Memory (ROM)

Read-Only Memory (ROM) is read out non-destructively It works in this way and can only read but not write information. Once the information is written, it is fixed and will not be lost even if the power is turned off, so it is also called fixed memory. The data stored in ROM is usually written before being loaded into the whole machine. It can only be read out during the operation of the whole machine. Unlike random access memory, the stored content can be rewritten quickly and conveniently. The data stored in ROM is stable and will not change after a power outage. It has a simple structure and is easy to use, so it is often used to store various fixed programs and data.

The characteristic of ROM is that it can only read information but cannot write information. Usually, a basic input/output system is solidified in the ROM of the computer motherboard, called BIOS (Basic Input Output System) . Its main function is to complete the power-on self-test of the system, initialization of each functional module in the system, basic input/output driver of the system and boot operating system.

There are many types of ROM, and each type of read-only memory has its own characteristics and scope of application. According to its manufacturing process and function, there are five types of ROM, namely mask-programmed read-only memory MROM (Mask-programmed ROM), programmable read-only memory PROM (Programmable ROM), erasable and programmable read-only memory Memory EPROM (Erasable Programmable ROM), electrically erasable programmable read-only memory EEPROM (Electrically Erasable Programmable ROM) and flash erasable read-write memory (Flash Memory).

Random Access Memory (RAM)

Random Access Memory (English: Random Access Memory, abbreviation: RAM), also called main memory, It is an internal memory that exchanges data directly with the CPU. It can be read and written at any time (except when refreshing), is very fast, and is often used as a temporary data storage medium for the operating system or other running programs. When RAM is working, information can be written (stored) or read (retrieved) from any specified address at any time. The biggest difference between it and ROM is the volatility of data, that is, the stored data will be lost once the power is turned off. RAM is used in computers and digital systems to temporarily store programs, data, and intermediate results.

Characteristics of RAM:

• Random access

  The so-called "random access" refers to when the memory When data is read or written, the time it takes has nothing to do with where the information is located or where it is written. In contrast, when reading or writing information in a Sequential Access storage device, the time and location required are related. It is mainly used to store the operating system, various applications, data, etc.

  When RAM is working normally, data can be read from RAM or written to RAM. Compared with ROM, RAM has the advantages of easy reading/writing and flexible use. It is especially suitable for situations where data is frequently and quickly changed.

• 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).

  The working characteristic of RAM is that after power is turned on, data information can be accessed at any location at any time, and the internal information will disappear after power is turned off.

• Sensitive to static electricity

  Like other delicate integrated circuits, random access memory is very sensitive to environmental electrostatic charges. 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.

• Access speed

  Modern random access memory has the fastest writing and reading speeds among almost all access devices, with access delays and other mechanical operations involved. It is also insignificant compared to other storage devices.

• Requires Refresh

  Modern random access memories rely 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.

For more related knowledge, please visit the FAQ column!

The above is the detailed content of What types of internal memory can be divided into?. For more information, please follow other related articles on the PHP Chinese website!