I am installing ubuntu 14.04 on an acer machine and I realize that the OS can't initialize if the booting files are lost.
I would really appreciate if somebody could bring information about how these files work.
Thank you very much.
There are several stages of booting in GRUB, each of them uses differect file(s)
Stage 1: boot.img is stored in the master boot record (MBR), or optionally in any of the volume boot records (VBRs), and addresses the next stage. At installation time it is configured to load the first sector of core.img.
Stage 2: core.img is by default written to the sectors between the MBR and the first partition, when these sectors are free and available. Once executed, core.img will load its configuration file and any other modules needed, particularly file system drivers; at installation time, it is generated from diskboot.img and configured to load the stage 3 by its file path.
_
This is a little piece of info, for full information check Wikipedia