Bootmgr-2. bcd-3. hal.dll-4. ntoskrnl.exe-the boot files have changed with the newer operating system. bootmgr has taken the place of ntldr and determines which operating system to boot. boot configuration data store (bcd) tells bootmgr the operating systems that can boot and their method of booting. hardware abstraction layer (hal.dll) allows applications to access devices without the application having to understand a specific protocol used by any one device. ntoskrnl.exe is the kernel image for 7 (and vista, xp, 2000), and is responsible for services such as process and memory management and hardware virtualization among other things.