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This article introduces you how the linux call process is, the content is very detailed, interested friends can refer to, hope to be helpful to you.

0) the core part of the computer is the arithmetic unit, controller, memory

1) the program must be loaded from disk to memory (RAM) in order to run. The disk belongs to the peripheral device, which is different from the memory.

Memory includes: RAM, ROM. ROM is a storage device driver command and is solidified so that it can only be read but not written. It is mapped to RAM (completed by hardware logic)

So that all peripherals can function properly. On the other hand, RAM stores general commands and data, and can write and read commands. All operations of CPU generally refer to RAM rather than ROM.

2) the program consists of instructions and data. In a computer, all instructions and data must be converted into binary in order to be identified. The reason: the arithmetic unit is hardware, electrically driven, and divided only.

Electricity and no electricity, no electricity means 0, electricity means 1. So the only data stored on disk that can be recognized by the computer is binary.

The disk has a memory function, each disk has many tracks, and converts the magnetic energy on the track into electrical energy, which is output for use by computers such as computers (especially calculators).

3) in order to simplify the data lines of the arithmetic unit, the time-sharing multiplexing of a batch of data lines is implemented, so that the operation of the arithmetic unit represents different meanings at different times.

In order for an arithmetic unit to complete a function (composed of multiple instructions), under the premise of bus time-sharing multiplexing, a register (buffer) is needed to temporarily record data.

Also known as registers, when the data and instructions are extracted and completed, the calculator can synthesize this information to complete a function at the same time, and the result is directed by the controller.

Stored in memory.

Note: memory stores not only instructions, but also data. They are all allocated to some unit space where memory is addressed under the direction of the controller.

4) instructions represent commands with different meanings (such as commands that represent additions, addends, and addition operators), and the controller tells the operator to hold

The operation order of the line command, and then take the data from the memory for the arithmetic unit to operate according to the command order, so as to realize the final function of the program.

5) memory is a storage unit that stores many addresses, and each small unit has a unique address, which can represent whether instructions or data are stored.

The memory mentioned above all refers to RAM memory, and there is another memory called ROM memory, which is used to store only all the devices used to drive the computer.

(keyboard, disk, mouse) commands, these commands stored in ROM are mapped to memory (RAM), and the arithmetic unit finds memory (RAM) through the scheduling of the controller.

These device commands and execute them, so that a boot mouse, keyboard, disk devices can work properly.

One small detail is that the arithmetic unit accesses memory (RAM) every N seconds to scan whether the keyboard, mouse, disk and other peripherals have been used by the user.

When the operation arrives, the corresponding command is executed to respond to the peripheral device. This is the way computers worked in the early days-- > the improved way is that users enter information through peripheral devices.

This information is accompanied by a signal that CPU has an instruction executed, which is placed in a space (called interrupt response space). When CPU receives a response, it may execute the corresponding information.

The command may not be executed, which CPU is in the active position in behavior, while the early CPU had to access memory every short time to see if there is

Command operation (especially whether the peripheral device has input) to execute the corresponding command, at this time the CPU is very passive and inefficient.

About how the linux call process is shared here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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