Boot Sequence Win2000/WinXP
Boot: The process of starting or resetting a computer is known as booting. The computer runs the software that loads and starts the computer's operating system.
Cold boot = When the computer is first turned on .
Warm boot= When the computer is reset without switching it off.
Basic Input/Output System (BIOS)
On x86-based computers, the set of essential software routines that test hardware at startup, start the operating system, and support the transfer of data among hardware devices. The BIOS is stored in read-only memory (ROM) so that it can be executed when you turn on the computer.
Master Boot Record (MBR)
The first sector on a hard disk, which starts the process of booting the computer. The MBR contains the partition table for the disk and a small amount of executable code called the master boot code.
Partition Boot Sector
A portion of a hard disk partition that contains information about the disk's file system and a short machine language program that loads the Windows operating system.
Boot Files
The files needed to start Windows. The boot files, in XP or win2000, are Ntldr, Boot.ini, Ntdetect.com.
System Partition
The partition that contains the boot files needed to load Windows. The system partition can be, but does not have to be, the same as the boot partition.
Boot Partition
The partition that contains the Windows operating system and its support files. The boot partition can be, but does not have to be, the same as the system partition.
Systemroot
The path and folder name where the Windows system files are located. Typically, this is C:\Windows, although you can designate a different drive or folder when you install Windows. You can use the value %systemroot% to replace the actual location of the folder that contains the Window system files. To identify your systemroot folder, click Start, click Run, type %systemroot%, and then click OK.
Boot Logging
A process in which a computer that is starting (booting) creates a log file that records the loading of each device and service. The log file is called Ntbtlog.txt, and it is saved in the system root directory.
Itanium
An Intel microprocessor that uses explicitly parallel instruction set computing and 64-bit memory addressing.
Extensible Firmware Interface (EFI)
In computers with the Intel Itanium processor, the interface between a computer's firmware, hardware, and the operating system. The Extensible Firmware Interface (EFI) defines a new partition style called GUID partition table (GPT). EFI serves the same purpose for Itanium-based computers as the BIOS found in x86-based computers. However, it has expanded capabilities that provide a consistent way to start any compatible operating system and an easy way to add EFI drivers for new bootable devices without the need to update the computer's firmware.
GUID Partition Table (GPT)
A disk-partitioning scheme that is used by the Extensible Firmware Interface (EFI) in Itanium-based computers. GPT offers more advantages than master boot record (MBR) partitioning because it allows up to 128 partitions per disk, provides support for volumes up to 18 exabytes in size, allows primary and backup partition tables for redundancy, and supports unique disk and partition IDs (GUIDs).
Cold boot = When the computer is first turned on .
Warm boot= When the computer is reset without switching it off.
Basic Input/Output System (BIOS)
On x86-based computers, the set of essential software routines that test hardware at startup, start the operating system, and support the transfer of data among hardware devices. The BIOS is stored in read-only memory (ROM) so that it can be executed when you turn on the computer.
Master Boot Record (MBR)
The first sector on a hard disk, which starts the process of booting the computer. The MBR contains the partition table for the disk and a small amount of executable code called the master boot code.
Partition Boot Sector
A portion of a hard disk partition that contains information about the disk's file system and a short machine language program that loads the Windows operating system.
Boot Files
The files needed to start Windows. The boot files, in XP or win2000, are Ntldr, Boot.ini, Ntdetect.com.
System Partition
The partition that contains the boot files needed to load Windows. The system partition can be, but does not have to be, the same as the boot partition.
Boot Partition
The partition that contains the Windows operating system and its support files. The boot partition can be, but does not have to be, the same as the system partition.
Systemroot
The path and folder name where the Windows system files are located. Typically, this is C:\Windows, although you can designate a different drive or folder when you install Windows. You can use the value %systemroot% to replace the actual location of the folder that contains the Window system files. To identify your systemroot folder, click Start, click Run, type %systemroot%, and then click OK.
Boot Logging
A process in which a computer that is starting (booting) creates a log file that records the loading of each device and service. The log file is called Ntbtlog.txt, and it is saved in the system root directory.
Itanium
An Intel microprocessor that uses explicitly parallel instruction set computing and 64-bit memory addressing.
Extensible Firmware Interface (EFI)
In computers with the Intel Itanium processor, the interface between a computer's firmware, hardware, and the operating system. The Extensible Firmware Interface (EFI) defines a new partition style called GUID partition table (GPT). EFI serves the same purpose for Itanium-based computers as the BIOS found in x86-based computers. However, it has expanded capabilities that provide a consistent way to start any compatible operating system and an easy way to add EFI drivers for new bootable devices without the need to update the computer's firmware.
GUID Partition Table (GPT)
A disk-partitioning scheme that is used by the Extensible Firmware Interface (EFI) in Itanium-based computers. GPT offers more advantages than master boot record (MBR) partitioning because it allows up to 128 partitions per disk, provides support for volumes up to 18 exabytes in size, allows primary and backup partition tables for redundancy, and supports unique disk and partition IDs (GUIDs).
When an Intel x86-based computer starts, sector 0, or the master boot record (MBR), is loaded from the first hard disk and executed. Sector 0 contains the partition table and some code, or the master boot code (MBC). The MBC scans the partition table for the single active partition and loads sector 0 from this partition into memory and executes it. This sector may be a utility or diagnostic program or a boot sector containing boot code for an operating system. The boot code starts the operating system in a manner defined by the operating system.
If a hard disk contains, for example, an MS-DOS, a Unix, and an IBM MOST partition, a user can change which of these systems will be started by changing the active partition. (If you are running MS-DOS, you can use FDISK to do this.)
Windows NT is started when a partition containing Windows NT boot code is active. The boot code loads the Windows NT Boot Loader. The Boot Loader enables you to choose which Windows NT installation is to be started, or to start the previous root-based operating system on the C drive.
The Boot Loader starts the root-based operating system by executing BOOTSECT.DOS, thus simulating the root-based operating system's ordinary boot sequence. BOOTSECT.DOS is usually the MS-DOS (or OS/2) boot sector, but this is not necessary. BOOTSECT.DOS could be another multi-boot program.
Each operating system provides one or more means of organizing data within partitions it recognizes. Some operating systems recognize and use the same file systems and some do not. For example, MS-DOS and Windows NT both recognize and use FAT partitions; Windows NT and Unix each use file systems that are unrecognizable by each other. Operating systems that recognize and use the same file systems can share partitions, meaning that a user can see files on such partitions from whichever of the operating systems is currently running.
If an operating system (like Unix) does not recognize the file system on the C drive, then it follows that the operating system cannot reside on the C drive and therefore the Windows NT Boot Loader cannot provide that operating system as a selection on its boot menu.
Also note that MS-DOS, OS/2, and Windows NT could all reside on separate partitions, in which case the user could select among them by changing the active partition. Or, MS-DOS and Windows NT could be on one partition and OS/2 on another. Or, as long as you keep the first partition FAT, you can have Windows NT and OS/2 on separate partitions, keeping only a bootable MS-DOS floppy for the times when you need to use MS-DOS.
If a hard disk contains, for example, an MS-DOS, a Unix, and an IBM MOST partition, a user can change which of these systems will be started by changing the active partition. (If you are running MS-DOS, you can use FDISK to do this.)
Windows NT is started when a partition containing Windows NT boot code is active. The boot code loads the Windows NT Boot Loader. The Boot Loader enables you to choose which Windows NT installation is to be started, or to start the previous root-based operating system on the C drive.
The Boot Loader starts the root-based operating system by executing BOOTSECT.DOS, thus simulating the root-based operating system's ordinary boot sequence. BOOTSECT.DOS is usually the MS-DOS (or OS/2) boot sector, but this is not necessary. BOOTSECT.DOS could be another multi-boot program.
Each operating system provides one or more means of organizing data within partitions it recognizes. Some operating systems recognize and use the same file systems and some do not. For example, MS-DOS and Windows NT both recognize and use FAT partitions; Windows NT and Unix each use file systems that are unrecognizable by each other. Operating systems that recognize and use the same file systems can share partitions, meaning that a user can see files on such partitions from whichever of the operating systems is currently running.
If an operating system (like Unix) does not recognize the file system on the C drive, then it follows that the operating system cannot reside on the C drive and therefore the Windows NT Boot Loader cannot provide that operating system as a selection on its boot menu.
Also note that MS-DOS, OS/2, and Windows NT could all reside on separate partitions, in which case the user could select among them by changing the active partition. Or, MS-DOS and Windows NT could be on one partition and OS/2 on another. Or, as long as you keep the first partition FAT, you can have Windows NT and OS/2 on separate partitions, keeping only a bootable MS-DOS floppy for the times when you need to use MS-DOS.
No comments:
Post a Comment