"To load an operating system into memory, you first need an operating system in memory!" - pg 119

Bootstrap Loader

First operating system: the bootstrap loader.

How is the bootstrap loader loaded into memory?

If the "real" operating system is on disk, how does the bootstrap loader know enough about the partitions and file systems on the disk to find the "real" operating system file(s).

Note: The bootstrap loader needed the correct disk driver to even access the disk.

1. Early systems statically linked device driver information into the os; drivers statically contained disk partition and file system information.
2. Later all possible device included and boot time probed to see which were actually needed - a little more flexible. Disk partion, etc. stored at known location on disk (i.e., first sector).
3. BIOS (basic input, output system) in read only memory, provides:
   • POST
   • load and trasfer control to boot program
   • provide drivers for all devices