boot managers present a menu of boot options or provide some other way to control the boot process. The user can then select an option, and the boot manager passes control to the selected tool
boot loaders handle the task of loading an OS kernel into memory, often along with support files such as a Linux initial RAM disk (initrd) file, and starting the kernel running

From an EFI/UEFI perspective, both boot loaders and boot managers are simply EFI/UEFI programs

Boot Loader and/or Boot Manager - Types

Type	Boot Loaders and/or Boot Managers	Deprecated?	BIOS and/or UEFI	Description
Master Boot Record (MBR)	N/A	PHASING OUT & IN SUPPORT	BIOS	is a partition scheme type
Grand Unified Boot Loader 2 (GRand Unified Bootloader (GRUB 2))	BOTH	IN SUPPORT	EFI/UEFI	superseded GRUB Legacy
Grand Unified Boot Loader Legacy (GRUB Legacy)	BOTH	PHASING OUT	EFI/UEFI	superseded by GRUB 2
Boot Camp Assistant		IN SUPPORT		is a multi-boot utility for installing Windows on Intel-based Macintosh computers support.apple.com/boot-camp Link to original
LInux LOader (LILO)	LOADER	DEPRECATED		is a Linux bootloader
gummiboot/systemd-boot	MANAGER
rEFInd	MANAGER	IN SUPPORT	EFI/UEFI	is a fork of the rEFIt boot manager like rEFIt, rEFInd can auto-detect your installed EFI boot loaders and it presents a pretty GUI menu of boot options rEFInd goes beyond rEFIt in that rEFInd better handles systems with many boot loaders, gives better control over the boot loader search process, and provides the ability for users to define their own boot loader entries Link to original
rEFIt	MANAGER	DEPRECATED	EFI/UEFI	is the out-of-development predecessor to rEFInd
SYSLINUX	LOADER	DEPRECATED
EFI Stub Loader	LOADER			this program turns a Linux kernel into its own bootloader. This means that a boot manager can launch a Linux kernel, much as a boot loader could

／var／log marcus chiu