1, the way of the disk connection and the device file name relationshipThere are two common disk interfaces of the PC, namely, IDE and SATA interface, the current mainstream is the SATA interface, but the older hosts mostly use the IDE interface. We call the device that can connect to the IDE interface as an IDE device, whether it's a disk or a disc device. IDE interface, because an IDE flat cable can connect two IDE devices, and usually the host will provide two IDE interfaces, so up to four IDE devices can be received . In other words, if you already have a CD-ROM device, then you can only connect to the disk with three IDE interfaces. These two IDE interfaces are often referred to as IDE1 (primary) and IDE2 (secondary), and the IDE devices above each flat cable can be distinguished as Master and slave. The file name for these four IDE appliances is:
| Ide\jumper |
Master |
Slave |
|
| IDE1 (Primary) |
/dev/hda |
/dev/hdb |
|
| IDE2 (secondary) |
/dev/hdc |
/dev/hdd |
|
|
|
|
|
For example: Suppose your host has only one IDE interface disk, and this disk is connected to the master of IDE2, what is the file name of his device inside the Linux operating system? refer to the table above, IDE2 's master device file is named/dev/hdcSATA interface, because the SATA/USB/SCSI and other disk interfaces are driven using SCSI modules, the disk appliance filenames for these interfaces are in the format/dev/sd[a-p]. However, unlike the IDE interface, the SATA/USB interface disk is not in a certain order, at this time, the device filename will be based on the Linux core detection of the order of the disk!! For example:if the PC has two SATA disks and a USB disk, the motherboard has six SATA slots. These two SATA disks are placed on the SATA1,SATA5 slots on the motherboard, what are the file names of the three disks in Linux? because the device file name is determined using the detected order, it is not related to the actual slot code, so the device has the following file name:file name on 1.sata1 slot:/dev/sdafile name on 2.sata5 slot:/dev/sdb3.USB disk (captured by the system after boot):/DEV/SDC2. Disk partition table (partition tables)
- The composition of the disk mainly consists of disk, mechanical arm, disk reading head and spindle motor, and the data is written in fact on the disk disc. Disk disks can be subdivided into sectors (Sector) and magnetic column (Cylinder) units, where each sector is 512bytes.
- The first sector of the entire disk is particularly important because he records important information about the entire disk. The first sector of the disk mainly records two important information, namely:
- Main boot Record area (Master boot record,mbr): Where the boot manager can be installed, there are 446bytes
- Split tables (partition Table): Record the state of the entire hard disk partition, 64bytes
- MBR is important because when the system is booting it will actively read the contents of the block, so that the system will know where your program is placed and how to boot. If you are installing a multi-boot system, the management of this chunk of MBR is very important.
- Since the partition table is only 64bytes, can hold up to four separate records, these four segmented records are called primary (Primary) or (Extended) split slots.
- The so-called "segmentation" is only for the 64bytes partition table to set;
- The default partition table of hard disk can only write four groups of segmented information;
- These four groups of split information we call the main (Primary) or extended (Extended) split slots;
- The smallest unit of a split slot is a magnetic column (cylinder);
- When the system is written to disk, it must refer to the disk partition table in order to process data for a split slot
- A simple definition of the characteristics of the main segmentation, extension segmentation and Logical segmentation:
- The main segmentation and extension can have up to four strokes (hard disk limit)
- There can be at most one extension split (operating system limit)
- The logical segmentation is the continuous cutting out of the segmented slots by the extended segmentation;
- Can be formatted, as the data access to the partition slot for the main division and logical segmentation. Extended segmentation cannot be formatted;
- The number of logical divisions varies by operating system, in Linux systems, the IDE hard disk has a maximum of 59 logical partitions (number 5th to 63rd), and the SATA hard disk has 11 logical partitions (5th to 15th numbers).
3. Boot process and main boot record area (MBR)CMOS is a storage device that records various hardware parameters and is embedded in the motherboard, and the BIOS is a firmware written to the motherboard (firmware is a software program written to the hardware). The BIOS is in the boot, the computer system will actively execute the first program!! The entire boot process to the operating system before the action:1.BIOS: Boot active firmware, will know the first device to boot;2.MBR: The first boot device in the first sector of the main start record block, including the boot management program;3. Boot Manager (boot loader): a software that can read the core file to execute;4. Core Archives: The function of the boot operating system ...boot loader's main tasks:Menu: Users can choose different boot items, which is also an important function of multi-boot! Load the Core archives: direct point to the bootable program section to start the operating system;Transfer Other loader: Transfer the power-on management function to other loader responsible for
Host planning and disk partitioning
