Beside the meaning of the ESP(EFI System Partition), is really just any partition formatted with one of the UEFI spec-defined variants of FAT and given a specific GPT partition type to help the firmware find it. This way, all EFI executables will be stored at one place, and "chainload" the Operating System specific loader or other EFI executables
The steps of booting with this setup are:
- System on - POST(Power On Self Test)
- UEFI loads it's firmwares, and initializes all hardware required for booting.
- Firmware determine what is the partition to be read, and where the UEFI applications are stored
- Firmware reads Boot Manager data to decide based on a list what EFI application have the highest priority to boot. Some UEFI systems are less flexible, and expect only one UEFI application that needs to be stored at
- UEFI application is launched. It may launch/chain another UEFI application(like an UEFI shell/menu) or load the initramfs and the kernel.
Basically, it's a FAT partition where you store EFI applications. The advantage here is that you don't need a "boot sector" anymore. It is a partition where you store binaries(efi files) and do whatever you want(depends on how your motherboard implements the specification).
Update answer: This partition will be shared in a way that a Linux related EFI(Gummiboot, rEFInd or Grub) and the Windows 8 standard EFI loader (
\EFI\Microsoft\Boot\bootmgfw.efi) will be stored on the same partition. Is up to you if you want to create menus directly on the EFI Firmware or using Grub to create entries to Windows and Linux. Example.
Unfortunately, Windows 7 32bit, and Windows Vista and older(no matter 32 or 64 bits) do not support EFI+GPT. You will have to use Bios + MBR solutions to dual boot.