What are the characteristics of cache, rom and ram?

Characteristics of cache: A one- or two-level high-speed, small-capacity memory set between the CPU and the main memory. Its information is naturally lost when the computer is powered off. Characteristics of ROM: 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. Characteristics of ram: it can read data from the memory and write information to the memory; it is used to store commands, programs and data required to run the program; information is naturally lost when the computer is powered off.

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

Memory is mainly divided into RAM (random access memory), ROM (read-only memory) and Cache (cache).

RAM (Random Access Memory):

Random access memory, commonly known as memory, the 8g computer memory we often refer to refers to this ( Not entirely correct either). RAM requires constant power supply at all times, otherwise data will be lost. It is made of semiconductor materials and is the working place of the computer.

Features:

• You can read data from the memory and write information to the memory

• Used to store commands, programs and data required to run programs

• Information is naturally lost when the computer is powered off.

ROM (Read Only Memory):

 Read-only memory, used for hard disk storage. Generally made of magnetic materials, it is used to store temporarily unused information. It can only be processed by the CPU when it is loaded into memory (RAM). That is, there is no direct data exchange between the CPU and the hard disk.

Features: Can only read data from the memory, but cannot write information into it. The data will still exist after the computer is powered off.

Cache (cache memory)

Cache is between the CPU and RAM. It is a memory that reads and writes faster than RAM. . When the CPU writes or reads data to RAM, it will be stored in the Cache simultaneously. When the CPU needs the data again, the CPU will read the data from the Cache instead of accessing the slower memory. If the required data is in the Cache No, the CPU will read the data in the Cache again.

Features: A one-level or two-level high-speed small-capacity memory set between the CPU and the main memory. Its information is naturally lost when the computer is powered off.

Access speed:

Cache>>RAM>>ROM

##RAM and The difference between ROM

Generally speaking, it is difficult to understand the relationship between RAM and ROM and the usual running memory and hard disk capacity. In fact, they are the same in a general sense, but From the perspective of computers and mobile phones, there are some differences:

It is generally easier to understand from the perspective of computers. RAM is what we usually call running memory, and it can indeed be read and written at any time. Because the data processed by the CPU is mediated by running memory. Information is not saved after a power outage. So for ROM, is it the hard disk? Doesn’t it mean that ROM can only be read? The hard drive can be modified. Indeed, it must be made clear that RAM and ROM are both memories, and the hard disk is external memory, so ROM is not equal to the hard disk. The ROM in the computer is mainly used to store some system information or start the BIOS program. These are very important. They can only be read and generally cannot be modified. They will not disappear even if the power is turned off.

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 disappear automatically and can be saved for a long time without power.

In a mobile phone, RAM is the same running memory as a computer; and ROM is connected to the hard disk. Part of the ROM in the mobile phone is used to store system information and some installation software, and the rest is large. Part of the capacity is used as a hard disk, which can be read and written.

The difference and connection between hard disk and memory

The difference between hard disk and memory is very big, the most important three points:

1. The memory is the working place of the computer, and the hard disk is used to store information that is not used temporarily.

2. Memory is made of semiconductor materials, and hard disks are made of magnetic materials.

3. The information in the memory will be lost when the power is turned off, but the information in the hard disk can be saved for a long time.

The connection between memory and hard disk:

The connection between memory and hard disk is also very close. Here is just one point: the information on the hard disk is never temporarily used. ? Please load it into memory! There is no direct data exchange between the CPU and the hard disk. The CPU only instructs the hard disk to work through control signals. The information on the hard disk can only be processed after it is loaded into the memory. Memory is where programs and data are stored. For example, when we use WPS to process documents, when you type characters on the keyboard, it is stored in the memory. When you choose to save, the data in the memory will be Store in hard (magnetic) disk.

The difference between memory and storage:

The difference between memory and storage: Most people often confuse the two names of memory and storage, especially when talking about their capacities. Memory refers to the capacity of the random access memory installed in the computer, and storage refers to the capacity of the hard disk in the computer. From the perspective of computer architecture, the hard disk should be the "external memory" of the computer. Memory should be some storage inside the computer (on the motherboard), used to save intermediate data and calculation results during the use of CPU operations. When these data are not in use, they are saved on the hard disk. In the computer industry, the term memory is widely used to refer to RAM (random access memory).

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