Introduction to the terminology of several USB disk startup settings

We will encounter a lot of relevant terminology in setting up the U disk startup process, and here are some common:

BIOS (Basic input/output System)

The basic input and output system, the full name is Rom-bios, is read-only memory basic input/output system shorthand, it is actually a group of curing to the computer, to provide the lowest level of the most direct hardware control program.

CMOS (complementary Metal oxide semiconductor)

The original meaning is the complementary metal oxide semiconductor, a large-scale application in the integrated circuit chip manufacture raw material, in the computer domain, the CMOS often refers to saves the computer basic startup information (for instance date, time, the start-up setting and so on) the chip.

CMOS power consumption is very low, the computer motherboard on the last button battery can give it a long time to provide power, even if the system loses power, information will not be lost. And when the motherboard battery power supply is not enough CMOS information will be lost, at this time to start the machine will have some special phenomenon, such as the start of the hint CMOS parameter loss to reset, and even the machine black screen, can not start, replace the motherboard button battery is back to normal.

Sometimes people will mix CMOS and bios, in fact, CMOS is the motherboard on a read-write RAM chip, is used to save the BIOS hardware configuration and user settings for certain parameters. And the parameters of the CMOS set to pass a special program, most manufacturers now do the CMOS Setup program in the BIOS chip, in the power-on by pressing a specific key can enter the CMOS Setup program and very easy to set up the system, so this CMOS settings are often called BIOS settings.

ESCD (Extended System Configuration Data)

Extended System Configuration data, ESCD is the system BIOS used to exchange hardware configuration information with the operating system, which is stored in the CMOS (a small piece of special ram, powered by the battery on the motherboard), usually ESCD data will only be updated when the system hardware configuration has changed.

Sector (sector)

The smallest unit of hard disk partition, one sector fixed to 512 bytes (byte).

MBR (Master boot Record)

That is, the master boot record, sometimes referred to as the primary boot sector. 0 sectors located throughout the hard drive (the 0~62 of the hard drive is the reserved sector, the first 63 sectors currently, only the MBR occupies the first or previous sectors of the disk, it can be viewed as the first sector of the hard drive, which typically occupies only one sector, such as XP Mbr,grub4dos occupies a total of 18 sectors 0~17 。

DBR (DOS boot Record)

The operating system boot record area, also known as the partition's master boot code, the No. 0 sector of the partition, which typically occupies only one sector, occupies other reserved sectors in particular, and grub4dos does not modify or use DBR if it is written to the hard disk MBR, indicating that the number ends with H or begins with a number of 0x The hexadecimal number.