Boot manager
A boot manager (from the English bootstrap loader from bootstrap for "boot loop" and loader for " loader program" via the abbreviation boot loader for "bootstrap" and manager for "administrator" for further shortening boot manager ) is a utility that - if available - the Allows selection of several operating systems when starting up ( booting ) a computer .
Boot process
The boot manager is a program that enables different operating systems to be selected on one computer. When a computer starts up, the BIOS is started , among other things , and continues from there using a so-called boot code , which it finds in the master boot record (MBR) on sector 0 of a hard disk. This contains the sector address of the storage medium on the boot loader or boot manager to be loaded . As a rule, sectors 1 ... 62 of a hard disk are unused and can be used for boot manager code. The boot manager displays a menu in which the bootable operating systems can be selected.
Alternatively, the bootloader can also start a rudimentary operating system in which a correspondingly more comfortable boot manager menu is possible. If the operating system that has now been selected has already been loaded - i.e. the one under which the boot manager is running - the further configuration of the operating system is continued, otherwise the boot manager starts the boot loader for the alternative operating system. In order to find its start address, the boot manager needs the associated MBR . If different operating systems were installed on the same storage medium, this must therefore be located at the beginning of an additional partition - the so-called boot sector of the installation partition .
alternative
Some boot loaders also offer the choice of operating system described here . In general, the two terms boot manager and boot loader are therefore used synonymously today. In contrast to the boot manager, which requires a more extensive operating system, the boot loader only uses functions of the BIOS .
