CPU, memory, and hard disk

CPU is short for central processing unit, which is commonly known as "computer brain ",

It processes and computes all data in the computer!

The CPU extracts commands from the memory or cache and puts them into the instruction register,

The command is decoded into a series of micro-operations, and various control commands are issued to execute the micro-operation series!

Why don't I get the data from the hard disk when the CPU calls data from the memory?

Because the hard disk speed is slow, it can be said that the hard disk is the only hardware that relies on mechanical operation,

The CPU obtains data from the hard disk, as if the supply is in short supply, and the CPU running speed is greatly reduced due to the bottleneck effect,

This affects the running speed of the entire machine! The memory can effectively solve this operation bottleneck problem!

All programs in the computer run in the memory, so the memory performance has a great impact on the computer.

The memory is like a "high-speed lane". Data is transmitted to the CPU through a slow hard drive!

But the memory is charged for storage (data will disappear once power-off), and the capacity is limited, so it takes a long time to store programs or data to use the hard disk.

Slow hard disk speed also affects the speed of the entire machine, because the speed at which the system reads data from the hard disk and saves the data to the memory through the bus also affects the system operation speed.

The memory size is always limited. What if the data to be read exceeds the actual size of the physical memory?

At this time, the virtual memory can play a role,

The system stores temporarily unavailable programs or unused data in this part of the virtual memory, so that it can be conveniently called as needed.

This article is from the "My Java World" blog, please be sure to keep this source http://hanchaohan.blog.51cto.com/2996417/1438920