Learning from Linux (3)--host planning and disk partitioning

Anyway, now also can not sleep, the game has a period of time to start, then stay up late to write some experience it, mainly for the third chapter host planning and Disk partitioning.

I'm not sure at first that Linux doesn't just need to master some important instructions. But later in the project to port a Linux system to the ARM chip, only know the need to master the entire Linux system, as we need to master the Windows system before it can operate.

1. All the information, data, etc. in Linux are recorded in the form of files, and more generally, each device is accessed as a file, for example, the hard disk file name of the IDE interface is/DEV/HDA and so on. The data is actually written on the disk. Disks can also be subdivided into sectors and two units of magnetic columns, each with a sector size of 512 bytes, the most important of which is the first sector.

2. The first sector mainly records two important information: 1) The main boot record area (MBR), Storage installation boot management program, the size of 446 bytes. 2) split the table to record the state of the entire hard disk partition, the size of 64 bytes. MBR is important because when the system is powered on, it will actively read the contents of this chunk, so that the system knows where your program is placed and how to boot.

3. In the partition Table of 64 bytes, a total of four groups of records, each group recorded the beginning and end of the section of the magnetic column number, assuming that the hard disk device file name is/dev/hda, the partition slot four sections are/dev/hda1,/dev/hda2,/dev/hda3,/ Dev/hda4. The four groups of split information is called an extended divider, and the smallest unit is the magnetic column. A logical divider can be cut out by an extended split slot and the device name number can only be started from 5.

4. Simply put, the entire boot process to the operating system before the action should be such: 1) BIOS, boot active firmware, will know the first bootable device 2) MBR, the first boot device first sector of the main boot record block, including the boot management program. 3) boot loader, a software that can read the core file to execute. 4) core files, that is, the kernel, start the function of the operating system.

Learning from Linux (3)--host planning and disk partitioning