

What types of memory are divided into? What are the main components and characteristics of each type?
The memory unit is actually a type of sequential logic circuit. According to the type of memory usage, it can be divided into read-only memory (ROM) and random access memory (RAM). The functions of the two are quite different, so their descriptions are also different.
The storage media that make up the memory mainly uses semiconductor devices and magnetic materials. The smallest storage unit in memory is a bistable semiconductor circuit or a CMOS transistor or a storage element of magnetic material, which can store a binary code. A storage unit is composed of several storage units, and a memory is composed of many storage units.
There are several different classification methods of memory based on the performance of the storage material and how it is used. (Recommended learning: web front-end video tutorial)
1. Classification by storage media
Semiconductor memory: a memory composed of semiconductor devices.
Magnetic surface memory: A memory made of magnetic materials.
2. Classification by storage method
Random access memory: The contents of any storage unit can be randomly accessed, and the access time has nothing to do with the physical location of the storage unit.
Sequential memory: It can only be accessed in a certain order, and the access time is related to the physical location of the storage unit.
3. Classification according to the read and write functions of the memory
Read-only memory (ROM): a semiconductor memory whose stored content is fixed and can only be read but not written.
Random read-write memory (RAM): Semiconductor memory that can be both read and written.
4. Classification according to the storability of information
Non-permanent memory: memory in which information disappears after power failure.
Permanent memory: memory that can still retain information after power is turned off.
5. Classified by its role in the computer system
Main memory (memory): used to store active programs and data, with high speed, small capacity, and high price per bit.
Auxiliary memory (external memory): It is mainly used to store currently inactive programs and data. It has slow speed, large capacity and low price per bit.
Buffer memory: Mainly plays a buffering role in two components with different working speeds.
The above is the detailed content of What types of memory are divided into? What are the main components and characteristics of each type?. For more information, please follow other related articles on the PHP Chinese website!

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The fastest access memory is "internal memory"; the memory in the computer adopts a hierarchical structure, arranged in order of speed, including internal memory, cache memory, the computer's main memory, and large-capacity disks. The memory is generally divided into RAM Random Access Memory and ROM Read Only Memory.

Can be accessed directly. Internal memory, also called memory, is the bridge between external memory and the CPU. All programs in the computer run in memory. The function of memory is to temporarily store calculation data in the CPU and data exchanged with external memories such as hard disks. As long as the computer is 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 operation of the memory also determines the stable operation of the computer.

The basis for a computer to have a strong memory capability is a storage device with sufficient capacity. Memory can be divided into internal memory and external memory. They enable computers to have powerful memory functions and can store large amounts of information. This information includes not only various types of data information, but also programs for processing these data.

The memory system refers to a system in a computer consisting of various storage devices that store programs and data, control components, and devices (hardware) and algorithms (software) that manage information scheduling. The storage system provides the ability to write and read information (programs and data) required for computer work, and realizes the computer's information memory function. The hierarchical structure of the storage system can be divided into five levels: register group, cache cache, main memory, virtual memory and external memory.

The USB flash drive was invented in China, and Netac is the global inventor of the USB flash drive. In July 2002, Netac's "Fast Lightning External Storage Method and Device for Data Processing Systems" was officially authorized by the State Intellectual Property Office. This patent filled the 20-year gap in invention patents in the field of computer storage in China; 2004 On December 7, 2019, Netac received the basic invention patent for flash disks officially authorized by the U.S. National Patent Office.

Cache is called cache memory. It is a high-speed small-capacity memory between the central processing unit and the main memory. It is generally composed of high-speed SRAM. This kind of local memory is oriented to the CPU. It is introduced to reduce or eliminate the gap between the CPU and the memory. The impact of the speed difference between them on system performance. Cache capacity is small but fast, memory speed is low but capacity is large. By optimizing the scheduling algorithm, the performance of the system will be greatly improved.

Memory is a memory device used to store programs and data, as well as intermediate results and final results of operations. The difference between internal memory and external memory: 1. The memory is a temporary storage area when executing the program, and all data will be lost after a power failure; the external memory is used to store original data and operation results, and the data will not be lost after a power failure; 2. Memory is characterized by fast access speed, but small capacity and expensive price, while external memory is characterized by large capacity, low price, but slow access speed; 3. Memory is used to store programs and data that the computer needs to use immediately. Memory is used to store programs and data that are not in use temporarily.

The characteristic of ROM memory is that it can only read data from the memory, but cannot write information into it. The data will still exist after the computer is powered off. ROM read-only memory 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 automatic power-on of the system. Inspection, initialization of each functional module in the system, basic input/output driver of the system and booting the operating system.