November 01, 1998 04:01 PM

Inside the Boot Process, Part 1

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Windows IT Pro
InstantDoc ID #3952
Understand NT's initialization sequence
The boot process is the first of three major phases Windows NT goes through during one cycle of normal operation. The other phases are normal operation and shutdown. Although this column and other articles in Windows NT Magazine have extensively covered the details of NT's policies and mechanisms during normal operation, the boot process is not usually covered in depth (for a selection of these articles, see "Related Articles ...

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It was very useful. It has helped me a lot in understanding the cause of start up problems.

Anonymous User 5/16/2005 12:33:00 AM


simplfy please

jack woods 4/1/2004 11:43:13 AM


If I'm not mistaken, XP is an NT based OS, right? So when installing XP while previous OS's are installed, a bootsect.dos file should be created, right? I have three primary partitions on my one and only harddrive. the first is a fat16 partition with DOS5 installed on it. the second is a fat 32 with 98 installed on it. I have been using a linux boot disk to create my partitions. I booted to the linux boot disk to create a third partition. I gave it a fat 32 file system and installed XP on it. Before i installed XP on the third partition, I had to change my two previous partitions to obscure file systems (I chose the "Amoeba" file system) so XP wouldn't install overtop of the OS's installed on the fat16 or fat 32 file systems. After I installed XP, I booted back to the linux boot disk and changed my Amoeba file systems back to the original fat 16 and fat 32 that they were. my OS's are still intact. However, I couldn't find a bootsect.dos file in the root directory of my XP partition. Shouldn't XP contain this file so I can continue to boot into other partitions using XP's boot.ini? I added ARC lines to my boot.ini to see if I could get to my dos and 98 partitions that way. I get a message stating "missing hal.dll" when i choose either DOS or 98 from the XP boot menu. I know both DOS and 98 are still intact, I just can't get to them through XP, b/c I can't find the bootsect.dos file. Do you know what i could do to retrieve my DOS and 98 boot partitions? Email at nyount@comcast.net

Nancy4/3/2003 1:05:09 PM


The article was to me a curtain raiser.Especially when for a long time I wondered how multi-boot option works.I had few guesses but all were wrong.The MSDN DDK doen't describes these topics so well.I am thankful to you

Ashish Chauhan 2/20/2002 8:19:41 AM


The major difference between 95/98 and NT is the use of the FDisk and the Format command. The article indicates that the Fdisk in 95/98 or the Setup program is the program that puts the IO.SYS or NTLDR "hooks" or reference into the boot sector of the disk. Actual what happerns in 95/98 the process is that FDisk defines the structure of the disk from the original "raw" disk state and either the command SYS or FORMAT /s allow the boot sector to be populated with the relevent hooks described above ie IO.SYS. In the NT environment there is no FDISK command or FORMAT with the switch /s. Thus every time the FORMAT command is used in NT it, by default inserts the "NTLDR" hooks in the boot sector so that the partition can be bootable. The actual boot process then looks for the first active partition as describe. This process is important to understand when you use NT Mirroring and discover that the boot sector has not been copied from the source disk.

Antony Urban 4/2/2000 4:56:35 AM


Windows NT Magazine has proved to be an invaluable resource for me as an infrastructure analyst working with NT. Many articles have provided guidance just when I’m ready to implement a solution.
Mark Russinovich’s NT Internals: “Inside the Boot Process, Part 1” (November 1998) contains an error in the last paragraph on page 59. The author writes, “For example, when NT Setup writes the MBR to a hard disk, it also writes a boot record to the first bootable partition of the disk.” The correct term is boot sector, instead of boot record. Otherwise, the text implies that Master Boot Record (MBR) and a boot record exist.
The article also should have mentioned that a successful boot is one in which a successful logon has occurred, and only then is the recent boot saved as Last Known Good.

—–James E. Haefele




You’re correct; boot sector is the appropriate term. In “Inside the Boot Process, Part 2” (January 1999), I explain Last Known Good in detail. Briefly, it is a copy of HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet that NT makes after all the auto start drivers and services have successfully initialized. This action doesn’t depend on anyone logging on.
--Mark Russinovich


James E. Haefele 8/6/1999 2:14:59 PM


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