The book used is Brother Bird's linux private kitchen
1. Basic computer knowledge
Input + host + output structure. Input includes keyboard mouse, touch screen, etc. The host contains CPU, RAM. Output to screen, printer.
There are two types of cpu, RISC and CISC. The former is used for large workstations, servers. The latter applies to various personal computers. The difference is in the complexity of the instruction set.
A common sense, X86 architecture. The originator of all chips was Intel's 8086, so it was later commonly known as the X86 architecture. Future expansion will only increase the number of transistors and the number of bits. 64-bit CPU is also called x86_64.
Two camps, AMD and intel. Intel's chips are divided into north and south bridges, and the north bridge is connected to CPU, RAM, and graphics cards with high computing speed. The south bridge connects the hard disk, USB and other devices. AMD does not have a north bridge, and the RAM interacts directly with the CPU.
A little math problem. 1024x768 resolution monitor. Each pixel occupies 3bytes. How much memory consumption? Answer: 1024x768x3=2.25M video memory
Computers can only distinguish 01, so it is a very painful thing to deal with directly with computers. In order to solve the problem of using complex and cumbersome mechanical codes, humans invented compilers. Common C, java. This makes writing programs much easier. But this creates another problem. Faced with a lot of hardware, it is very troublesome to write drivers for one hardware and one hardware. It would be nice if there was a common interface to call them. The operating system came into being.
Rearrange the architecture of a computer. Hardware, core, system calls, programs. Four parts. Among them, the core and system calls are wrapped up by the operating system alone, and the work of these two parts is done by it. The operating system is like a bridge, connecting software and hardware. The program does not need to consider the hardware, just write the logic with peace of mind. call to the operating system. The hardware does not need to be adapted to the software separately, it can be called by the operating system.
Summary: A computer is a device that accepts user instructions and data, and generates useful information after processing by the CPU math and logic unit.
2. The past and present of linux
In the early days, computers were more expensive, and people wondered if it could be shared by many people. The processing speed of the computer is fast. We use several small terminals to log in to a large computer. The computer has been running at full capacity, and the efficiency is much higher. So people researched a system that could share the host with multiple people, and it failed. But a young man who participated in the research wanted to make a small operating system to play with, so that he could use a small computer easily. So developed unix, the predecessor of linux. Later, the owner of the company decided to charge and commercialize it. So this guy's invention slowly became less popular. The copyright issue affects students the most, so an old professor wrote a minix, which is open source and has no copyright. As a teaching software, it is used by students. Limited by the professor's vision, this operating system is for teaching purposes. Many functions are click-through. At the same time, the voice of GNU advocating free software is getting louder and louder. The software itself should be free and open source for everyone to use. A Finn is convinced, and he believes that open source means more people working on a thing. Similar to Wikipedia today. So he wrote a core module and put it online. For everyone to download, everyone found that it is good to use, and because of the source code, many people participated in the process of perfecting this operating system. Since then linux was born. Due to open source software, there are many versions. Incidentally, open source software does not charge money, and the services that come with it need to be paid.
3.Linux system installation
I use a virtual machine, so I don't pay much attention to this chapter. Just get a general understanding.
4. First login
Enter su at the command line and enter the password to enter the privileged user mode. Linux input password may not display black dots, just press Enter after entering the password. There is no bad news, just good news.
Simple instructions. ls shows, ls -al shows permissions. date to view the date, cal to display the calendar, and bc to be the calculator. If you need to accurately calculate bc, you need to enter scale=3 (numbers are fine, take 3 as an example). tab completion command line. man+ command to enter the help page.
Shutdown: shutdown, scheduled shutdown shutdown down 11:55 (a time written at random). Restart reboot