Lossary - ACRONIS TRUEIMAGE DELUXE User Manual

Appendix B. Glossary
Active partition. One of the primary partitions of a hard disk is usually active.
Default MBR code tries to boot an operating system from the active partition
of the first hard disk. Letter assignment in Microsoft operating systems
depends on what partitions are active.
Bad cluster. A cluster that contains bad sectors. Such cluster cannot store
useful information.
Bad sector. A sector that cannot store the information written, for instance
due to defects or aging of the magnetic surface.
BIOS extension. BIOS versions that were released before 1994 could only
support hard disks that were less than 8 gigabytes. Extended hard disk
management functions were added to BIOS versions to solve this problem,
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and now the maximum supported hard disk capacity is 2 bytes.
Boot partition of an operating system is a partition from which the initial stage
of operating system booting is done (boot sector is read and executed, first
file of the operating system is read and executed).
Boot record. The initial part of a partition that contains code and data
necessary for booting an operating system. May consist of one or several
sectors. First sector of a boot record must end with the boot sector signature
(0AA55h).
Boot sector is the first sector of a disk or a partition that contains the initial code
for the operation system booting. Boot sector must end with 0AA55h signature.
Bootable disk is a disk from which an operating system may be booted. A
bootable disk must contain the boot sector of an operating system and the
necessary system and configuration files. The «Bootable disk» term usually
refers to diskettes and CD-ROMs.
Bootable partition. A partition that can host an operating system. In the
beginning of such a partition, there must be a boot record.
Booting an operating system is initialized by reading its boot sector to the
memory at 0:7C00h and passing control to it. Since each operating system
has its own boot sector, it is able to perform the required actions on loading
and initializing system and configuration files.
86 Appendix B : Glossary