April 2nd 2014
March 26th 2014
March 20th 2014
March 10th 2014
Feb 15th 2014
How the latest Windows operating systems
use the Disk Signature in their boot process.
Booting Windows.
There comes a point during the computer boot sequence when control is passed to a Windows component on the boot hard drive. From Windows Vista onwards this component is called bootmgr and this is the Microsoft bootmanager that has taken the place of the previous ntldr bootmanager that was part of XP and earlier WinNT operating systems. Just like the ntldr before it this new bootmanager is capable of booting not only the WIndows install it is a part of, but also other Windows operating systems that you may have on separate partitions or on additional hard drives in the PC. Unlike the ntldr however the bootmgr uses the disk signature to locate the hard drive that it wants. When bootmgr is tasked with starting an operating system it will scan all connected hard drives looking for the disk signature of the drive that the target OS is on. If the sought after signature is not found then bootmgr cannot continue with its task and so will stall with an error message. Even if you only have one hard drive and one operating system the disk signature check is still a default part of the boot process, hence issues with the disk signature can affect not only multibooters, but any Windows machine, (for GPT styled hard drives - see side box below).
Finding winload.exe
How to Lose a Disk Signature.
Moving Windows to a Different Hard Drive.
The other crucial factor when moving new Windows is the starting sector of its partition. The bootmgr program uses sector numbers to locate partitions and so if the start of a partition has moved on a drive then the number of the first sector will have changed and bootmgr will fail to find that partition and consequently winload.exe, so the familiar error message will appear. For a much fuller examination of the new Windows boot files and how they operate.... see The New Generation Boot FIles - bootmgr and BCD.
Operating systems have to be GPT aware to use such drives and the Windows OSes that can will no longer use MBR signatures to identify them but rather a unique GUID number that each drive will already have as part of the GPT partitioning scheme. These GUID numbers will be considered and even called the drive's disk signature and will be used in the boot process in the same way MBR signatures are used on traditionally partitioned drives. MBR or GPT
The Vista/7 Boot FIles - bootmgr and BCD.
Resolving a Disk Signature Collision.
Guide to WinRE (Windows Recovery Environment)
The Windows System and Boot Partitions
Manually Fix a Windows Disk Signature issue
Generalizing the Boot Configuration Data store
Making all your Windows installs independent
The IT-pro's deployment tool Sysprep will among other things prepare a Windows install to expect a few changes the next time it is booted. The generalize command will remove bootmgr's disk signature dependence for the very first reboot, so allowing it to find and boot Windows, then adapt itself to its new surroundings and to a changed or missing disk signature. This is only reliable for boot drive primary partitions and for simple and native Microsoft configurations. With Windows-7 it became the default configuration to have separate System and Boot partitions and so the sysprep tool was updated to prepare bootmgr on the system partition to find Windows on a different boot partition. Again this is only reliable for basic and native Microsoft configurations.
Sysprep Technical Reference New BCD Element
All product and company logos, icons and images that are reproduced on this site are the property and trademarks of their respective owners and are used here merely to illustrate their products, NOT to indicate or infer any endorsement or partnership unless otherwise stated. We have endeavored not to reproduce copyrighted images or graphics or infringe upon the rights of any trademark or copyright holder. If you believe or suspect we may have breached the permissible use of copyrighted material then please bring it to our attention. The reproducing or copying of original material from this site is currently allowed for non commercial purposes with the provision that your source is clearly indicated and that a back-link to the referenced information is included. Thank You. See our full Terms of Use. Material on this site is not guaranteed to be free of errors. Multibooters.com 2012 - 2013