Boot Loaders
Okay, so let's talk Bootloaders. A boot loader, or bootstrap loader, is the very first program that starts everytime you turn your computer on. It's launched by a boot medium, be it a hard drive, DVD, or USB device. The boot loader acts as a mediator between your hardware and the Operating System by transfering control of your System to the Operating System. What happens is your system's firmware goes through data carriers in a specific sequence, checking for a bootloader by means of a Boot Record. It starts with removable media, such as a boot disk or USB. If it can't find a bootloader in any of those, it'll check the hard drive, looking for the MBR(Master Boot record). If the bootload is found, the the Operating system is then loaded and you're on your way to happy times. If it can't find a boot record, or your boot record is corrupted, it'll pop up an error and you get to enjoy the pleasure of trouble shooting! Typical, most Linux distros use the GRand Unified Bootloader(or GRUB, with GRUB2 being the default Bootloader in Ubuntu 9.10). It supports LBA(Logical Block Addressing) and helps provide maximum flexibility in loading the OS. The boot options can also be modified with the GRUB command line. GRUB2 is a descendant of GRUB and is the default Bootloader for the Ubuntu distro as of Ubuntu 9.10. It supports scripting such as conditional statements and functions, a rescue mode, non-x86 platform support, the ability to boot LiveCD ISO images directly from your hard drive, and a brand spanking new configuration file system as well as universal support for Universally Unique IDentifiers(UUID). GRUB2 also allows more customization options such as themes, custom menus, and pretty splashyscreens.
