Overview #
- At startup, the computer runs a bootstrap program which then loads the OS into memory
- Uses EEPROM (electrically erasable programmable read-only memory) or similar schemes to store the bootstrap program since RAM is volatile
- Generally this program is simple and stored in firmware. It must know how to locate the OS and start executing it
- Once the kernel loads it will start providing services (e.g. Linux starts systemd which starts a bunch of other services)
GRUBis a bootstrap program for linux- Kernel parameters for bootstrapping can be found in
/proc/cmdlinerootis the root file system identifier
systemdis the first process on the system
Boot Process #
-
- The bootloader locates the kernel
-
- The file containing the kernel is loaded into memory and started
-
- The kernel initializes the hardware
-
- The root file system is mounted