Computer disk knowledge

• A disk consists of disks, cylinders, tracks, and sectors. The relationship between them is that a track is formed by a small sector (512 bytes per sector) in a circle, and a disc is projected from the disk to the bottom of the track, that is, a cylindrical disk, multiple disks form one disk.
• The first sector is composed of the primary boot partition (MBr, 446 bytes) and the partition table (64 bytes.
• MBR: During the startup of a computer, the BIOS (a software) looks for the MBR location in the first sector of the hard disk. Here, the MBR stores a boot program, which points to the address of the boot program of the system. Each sector will have a boot sector. Here, the boot load program of the corresponding system is stored. This program is added for system installation. It can identify the kernel file of the system, the next step is to boot the Kernel File System.
• Partitioned table: it has only 64 bytes of space. Up to four partition records can be stored here. Why are there four primary partition records and extended partition records? Because a record will take up 16 bytes of space, how are 16 bytes allocated here http://blog.tianya.cn/blogger/post_read.asp? Blogid = 2120302 & postid = 22245025 so the sum of the primary and extended partitions cannot exceed four, but the extended partitions cannot exceed one? Extended partitions cannot be used directly and are simply formatted. They consist of at least one logical partition.
• In Linux, the name of the device file in the primary partition. When all the files are in the primary partition, there are hda1 to hda4. When there are m partitions in total and the nth partition is an extended partition, then the primary partition name has hda1-hda (n-1), the logical partition by hdan-hda (m)

1. P1:/dev/hda1
2. P2:/dev/hda2
3. P3:/dev/hda3
4. ...

Computer disk knowledge