Brother Niao’s Linux Private Cooking-Chapter 1, 2, and 3

Preface

  This book is very interesting, but the author mentioned a lot of digressions, which seems a bit verbose. I read the first two pages quickly and did not take notes, so I will just excerpt the key points summarized by the author here for future reference. Review and association.

Chapter 1, What is Linux and how to learn it

  This chapter talks about too much Linux history and related materials. I feel like I can’t remember it after reading it. If you are interested, you can read it.

• The operating system (Operation System) mainly manages and drives hardware, so it must be able to manage memory, manage devices, be responsible for process management, system calls, etc. Therefore, as long as the hardware can be ready (Ready), it is a good operating system.
• The predecessor of Unix was written by Ken Thompson of Bell Lab. using a combination language. It was later rewritten in the C programming language by Dennis Ritchie from 1971 to 1973, and it was called Unix.
• BSD (Berkeley Software Distribution) was released by Bill Joy in 1977. These are called Unix-like operating systems.
• In 1984, Andrew Tanenbaum began to produce the Minix operating system, which can provide source code and software;
• In 1984, Richard Stallman advocated the GNU project, advocated free software (Free software), emphasized that its software can be "freely obtained, copied, modified and redistributed", and standardized the GPL licensing model. Any GPL (General Public License) software You cannot simply sell its software, nor can you modify the software license.
• The Linux operating system was developed in 1991 by Finnish Linus Torvalds. In short, the success of Linux mainly lies in: Minix (Unix), GNU, Internet, POSIX and the emergence of virtual teams.
• There are quite a few licenses that conform to the Open source concept, and the more well-known ones are Apache / BSD / GPL / MIT, etc.
• Linux itself is the most youthful operating system, and its development website is set up at http://www.kernel.org. We also call the lowest level data of the Linux operating system "Kernel".
• Starting from Linux kernel 3.0, the odd and even numbered core version plans have been abandoned. The new plan uses the mainline version (MainLine) as the basis and provides long-term support versions (longterm) to strengthen the continuous maintenance of certain functions.
• The composition of Linux distributions includes: "Linux Kernel + Free Software + Documentations (Tools) + fully installable programs" to create a complete
  system.
• Common Linux distributions classifications include "commercial, community" classification, or "RPM, DPKG" classification
• When learning Linux, it is best to start from scratch and learn from the basics, find a book that suits you, and then you can learn through practice.

Chapter 2, Host Planning and Disk Partitioning

  This chapter is quite verbose, but there are still some knowledge points, (1) How to display hardware in Linux; (2) Disk partitions and Linux directory mounting; (3) System startup method—the first partition record of the disk There is a boot record area, which is the boot management program;

• When purchasing new computer hardware, factors that need to be considered include "game console/work machine", "performance/price ratio", "performance/wattage consumption", "support", etc.;
• Old hardware equipment may be prone to unknown crashes during operation due to storage problems or aging of electronic parts.
• Red Hat hardware support: https://hardware.redhat.com/?pagename=hcl
• In the Linux system, each device is treated as a file, and each device will have a device file name.
• Disk device file names are usually divided into two types. The actual SATA/USB device file name is /dev/sd[ap], while the virtual machine device may be /dev/vd[ap]
• The first sector of the disk mainly records two important pieces of information, which are: (1) Master Boot Record (MBR): where the boot management program can be installed, 446 Bytes (2) Partition table (partition table): records the status of the entire hard disk partition, 64 Bytes;
• In the MBR partitioning method of the disk, there can be up to four main and extended partitions. The device file name number of the logical partition must start with No. 5;
• If the disk capacity is greater than 2TB, the system will automatically use GPT partitioning method to process the disk partition.
• GPT partitions no longer have the concepts of extension and logical partitions. You can imagine that all partitions are primary partitions!
• When some operating systems use GPT partitions, they must be installed with the new UEFI BIOS format.
• The boot process consists of: BIOS–>MBR–>boot loader–>core file;
• The main functions of the boot loader include: providing menus, loading the core, and transferring control to other loaders.
• There are two places where the boot loader can be installed, namely MBR and boot sector.
• The files of the Linux operating system use a directory tree system, and the corresponding disk requires a "mount" action;
• For a simple partition for beginners, it is recommended that you only need two partitions: / and swap.

Chapter 3, Install CentOS7.x

  This chapter requires hands-on work!