RAM (Random Access Memory), also known as "random access memory", is an internal memory that directly exchanges data with the CPU, also called main memory (memory). It can be read and written at any time, is very fast, and is often used as a temporary data storage medium for the operating system or other running programs. RAM cannot retain data when 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).
ROM (Read Only Memory) is also called "Read Only Memory". The data stored in ROM is generally written in advance before being installed into the whole machine. It can only be read out during the operation of the whole machine, and cannot be rewritten quickly and conveniently like random access memory. The data stored in ROM is stable and will not change after a power outage;
Compared with RAM and ROM, the biggest difference between the two is that the data stored in RAM will automatically disappear after a power outage. The ROM will not disappear automatically and can be saved even if the power is turned off for a long time.
Generally speaking, it is difficult to understand the relationship between RAM and ROM and what is usually called 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 a computer perspective. RAM is what we usually call running memory. 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 disk 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.
So what about mobile phones?
In fact, a lot of confusion comes from misleading promotional information from mobile phone manufacturers. Because generally mobile phone manufacturers will say how many gigabytes of RAM and how many gigabytes of ROM there are; in a mobile phone, RAM is the same running memory as a computer; but ROM is different. Think about it, if it is only used to store some systems How many gigabytes of capacity are needed for information and boot programs? In fact, the ROM of the mobile phone is linked to the hard disk. Part of the ROM in the mobile phone is used to store system information and some installation software. Most of the remaining capacity is Use it as a hard drive.
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