??? ?????? ?? FAT ?? ??????? ????????

??????? ?? "??? ??????" ????? ?????? ?? ????? ?? ????? ?? ???? ?????? ?? ?????? ?? ?????? ??? ???????? ?? ????? ????? ???

?? ??? ?? ??? ???, ????? ?? ????????? ?????? ?? ????? ???????, ?? ???? ?? ??? ?????? ?? ???? ?? ????? ??? ??? ?????? ?? ?????? ???????? ????????, ?? ???????? ?????? ??????? ???? ???????? ??, ?? ?????? ??????? ???? ?? ??? ?? ???? ???? ??????, ?? ????? ??? ???? ?? ????? ?????? ?? ???? ?? ????

????? ??, ??? ???? ????? ?? ?? ????? ?????, ?? ?????????? anti-????? ?? ????? ????????????? ?????????? ?? ????? ???? ?? ??? ??????? ??? ??? ?????? ???, ??? ??, ??? ?????? ?? ????? ?? ??????? ?? ???? ??? ??? handy.

?? ???? ????? ???? ?? ?? ???? FAT ??? ?????? ?? ??????? ????????? ????? ????? ??????? ?? ????? ?? ??? ??, ?? ?? ???? ?? ??? ??????????? FAT ??? ?????? ?? ???????? ??? ?? ????? ???? ??? ??? ???? ????? ?? ?????? ???? ???, ?? ??? ????? ?????? ????? ?????? ????? ???????? ?? ??????? ???? ?? ??? ????? ?????? ???? ?? ???? ??? ????? ???????? ???? ?? ??? ????? ???? ?? ???? ?? ????? ????? ?? ????? ???? ???

???????? ?????? ?? ????? ??????? ?? ??????? ?? ????????? ???? ?? ??? ????? ??? ??, ???? ???? ???????? ??????, Microsoft ???????? ???????? ?? ???? ????????? ???? ???? ???? ???????? ?? ????? ?? ????? ????? ???? ????? ????? ???? ????? ?? ????? ??????? ?? ????? ?????

????????? ?? ??????

?? ???????? ??? ??? "????? ?????? ??? ??????" ?? ???? ????? ?????? ?? ??????? ??????? ??? ??????? ??????? ?? ???? ?? ??? ???????? ????????, ????????? ????????, ?? ??? composite ?? ?? ?? ???? ????????, ??????? ?????? ?? ??? ??? ??? mirrors, stripe ??? ???? ??, ?? ??????? ??? ?? ?????? ???

?????? ????? ?? ????? ??? ?????? ?? ????? ?? ???? ??????? ????? ??????, ?? ????? ??? ????? ?????? ?? ???????? ???? ?? ??? "?????? ??? ???????" ?? "MBR." ?? ??? ??? ?? MBR ????? ?????? ??? ?????? ?? ????? ?? ?? ?? ???????? ????, ?? ?? ????? ?????? ?? ????? ??????? ???????? ?? ????? ???? ?? ?? ????? ??? ????? ?????? ??? ?????? ?? ???? ?????? ?? ?? ???????? ??? ???? ???? ?? ???? ???

??? ?????????

??? ????????? 80 x x86-?????? ?????????? (?? ??? ??? ?????? RISC-?????? ???????? ??) ?? ????????? ?? ????????? ???? ?? ??? ????? ?????? ??? ?????? ?? ???? ????? ???? ??? ?????? ??? ????????? ??????????? summarized ?? ???? ???:

1. ???? ???? self ??????? (?? POST) ?????? ??????? ?????? BIOS ?? CPU.
2. BIOS ??? ?????? ?? ??? ??? "??? ??????." ?? ????? ???? ?? ??? ????????? ???? ??
3. BIOS ??? ?????? ??? ?????? ?? ???? ????? ?????? ?? ??? ???? ?? ?? ?? ?????? ??? ?? ??????? ???? ?? ??? CPU ???????? ??????????? ???? ??? ??? ??? ?????? ?? ??? ????? ?????? ??, ?? ??? 3 ??? ??? ?????? ?? MBR ??, ?? ??? ????????? ??????????? proceeds:
   
   
4. MBR ??? ?????? ??? ???????? ???? ?? "?????? ???????? ???????? ?? ???" ?? ?????? ???????? ??? ?????? ?? ??? ???? ?? ?? ?? ?????? ??? ?? ??????? ???? ?? ??? CPU ???????? ??????????? ???? ???

?? ????? ?? ??? ????? ??? ????????? ?? ??? ?????? ?? ????? ???????? ?? ?? ??? ?? ???????? ?????? ??? ???? ?? ??? ?? ?? ???? ??? ????????? ?? ????? ??, ?? ????? ???????? ?? ????? ?????? ????? ??? ??? ?? ??? ???

FAT ??????? Windows NT ??????? ?? ?? ??, ?? ????? ??? FAT ??? ?????? ?? ????????? ?? ????? ????? ?? ????? "NTLDR" ??? ?? ?????? ??? ??? ????, ?? ???????? ?? ??? ??? ??????????? ?? ??? ???

FAT ??? ?????? ?? ????

MBR ??? ?????? ?? ??? CPU ???????? ??????????? ???? ??, ??????? FAT ??? ?????? ?? ???? ??? ?????? ???? ????? ???????? ????? ??????? ?? ?? 80 x 86 ?? ??? CPU. ?????? ??? ?? ????????? ?? ???? "???" ??????? ???? constitute ?? ??? ?????? ?? ???? 3 ?????? ?? ????????? ?? ??? ???? ?? ??? ???? ?? ?? ?????? "????????." ???? ??? ????? ????? ?? ??? ??? ???? ??

"????? ??? ??????? ???? 8 ???? OEM ID ??"? ?????????? ?? ?????? ?? ?? ???????? ?? ???????? ?????? ??? ???????? ?? ????? ???? ???

OEM ID ????? ?? ?????? BIOS ???????? ????? ?? "BPB." ?? ??? ??? ???? ???? ?? ??? ????? ?? ??? ??? ???? ???, BPB ???????? ??????? ?????? ????? ?? NTLDR ????? ?? ?????? ????? ?? ??? ??? ?????? ?? ???????? ????? ??? ?? ???? BPB ????? ?? ????? ?? ??????? ??, ??????? ???? ???????? ????? ?? ????? ????? ???? ??? ?????? ??? ????? ??????? ?? ?? ??? ??, ??????? BPB ?? ???? ?? ????????? ?????? ??? ?????? ???? ?? ??? ?????? ???? ?? ????? ????? ???? ??? ??? ???? ?????? ???, ??? ??????? ???? ?? ???? ??????? ?????? ????? ??? ??, ???????? ???????? ??? fairly ??????? ?? ???? ???? ???? ???? ?? ????? ?? ?? ??? ??? variability ?????? ?? ?? geometries encapsulated BPB ??? ???

BPB ???????? ?? ??? ??? ????? (??????, unaligned) ???????? ????? ????? ?????? BPB ??? ???????? ????? ?? ???? ????? ?? ???? ???? ???? ??? ???????? ????? ?? ????? ???????? ?????? ????????? ?? ????? ??????: ?? ?? ??? ????????? ?????? ?? ?? ??????? ????? ??? ????? ??? ??????? ????? ?? ??? ????, ?? ?????? ?? ???, 512 ???? ??????

??????? ????? ????????: FAT ??? ????????? (?? "????? ???????") ????? ?? ???? ??? ?? ?? ?????? ????? ?? ??, ??????? ???? ??????? ?????? ??????? ??????? ????? ???????? ?? ?????? ?? ??????? ???? FAT ??????? ?? ??? ??????? ??????? ???? ??? ??????? ?? ???? ?? ?????? ??? ?? ????? ?? ??? ????? ??? 1, 2, 4, 8, 16, 32, 64 ?? 128 ???? ?? ???? ?? ???? ??????? ?? ??? "??????? ??????? ????" ?? ?? ??? Microsoft ???????? ??? ?????? ?????

??????? ????????: ?? ??????? ????? ??? ?????? ???? ???? FAT ?? ??????? ?? ?????????? ???????? ?? ?????? ??? ??? ????? ?? ?? ?? 1 ?? ??? ??? ???? ??????

FATs: ?? ????? ?? ???????? FAT ?????? ???????????? ?? ?????? ?? ??? ??????????, ?? ????? ?? ??? 2 ???

??? ????????????: ???? ?? ??? ???????????? ??????? ?? ??? ?????????? ??? ???????? ???? ?? ???? ?? ?? ??? ?????? ?? ??? ???? ??????? ????? ?????? ??, ?? ?????? ?? ??? ?? 512? ????? ????, ??? ??, ?? ?? ????????? ?? ????? ????? ???? ??????? ???? ?? ??? ???, ?? ?? ?? ????? ????? ?? ????? ?? ?? ???? ???????????? ???? ????? ????? ???? ??????? ?? ????? ?????? ???? ???? ??? ?????????? ??? ??????? ?? ?????? ???? ??? 511, ?????????? ?? ????? ?? ?? ?? ????? ?? ?? ???? ???????????? ??? ???? ???? ??? ?? ????? ???? ???? ???

???? ????????: ?? ????? ?? ????? ?????? ?? ??? ???????? ?? ?????? ????? ?? ??????? ?? ???? ?? ???????? ???? ??? ??? ????????? ?? ??? ?? ????? ??? ??? 0 ??, ?? ?? ???? ????? ?? ??? ??? ??? ?? ?? "??? ????????" ??? ?? ????? ?????

?????? ????????????: ?? ???? ??????? ?????? ????? ?? ?? ???? ??? ?????? ?? ????? ???? ?? ???? ????? ?????? ?????? ?? ?????? ???????????? ??? ?? ???? ?????? ?????? ?? ??? ???? ???? ???? ??? ????? ??? ?? ?????? ???????????? ???? ?? ?? ???? ????? ?????? ?? ??????? ?? ???? ???FAT ?? ????? ????????: ?????? ???????? ??? ?? FATs occupied ???????? ?? ?????? ?? ??? Given this information, together with the number of FATs and reserved sectors listed above, we can compute where the root directory begins. Given the number of entries in the root directory, we can also compute where the user data area of the disk begins.

Sectors Per Track and Heads: These values are a part of the apparent disk geometry in use when the disk was formatted.

Hidden Sectors: This is the number of sectors on the physical disk preceding the start of the volume. (that is, before the boot sector itself) It is used during the boot sequence in order to calculate the absolute offset to the root directory and data areas.

Large Sectors: If the Small Sectors field is zero, this field contains the total number of sectors used by the FAT volume.

Some additional fields follow the standard BIOS Parameter Block and constitute an "extended BIOS Parameter Block." The next fields are:Physical Drive Number: This is related to the BIOS physical drive number. Floppy drives are numbered starting with 0x00 for the A: drive, while physical hard disks are numbered starting with 0x80. Typically, you would set this value prior to issuing an INT 13 BIOS call in order to specify the device to access. The on-disk value stored in this field is typically 0x00 for floppies and 0x80 for hard disks, regardless of how many physical disk drives exist, because the value is only relevant if the device is a boot device.

Current Head: This is another field typically used when doing INT13 BIOS calls. The value would originally have been used to store the track on which the boot record was located, but the value stored on disk is not currently used as such. Therefore, Windows NT uses this field to store two flags:

• The low order bit is a "dirty" flag, used to indicate that autochk should run chkdsk against the volume at boot time.
• The second lowest bit is a flag indicating that a surface scan should also be run.

Signature: The extended boot record signature must be either 0x28 or 0x29 in order to be recognized by Windows NT.

ID: The ID is a random serial number assigned at format time in order to aid in distinguishing one disk from another.

Volume Label: This field was used to store the volume label, but the volume label is now stored as a special file in the root directory.

System ID: This field is either "FAT12" or "FAT16," depending on the format of the disk.

???? ??? ???? ????? ??????? ?? ??????? ??????? BIOS ???????? ????? ????? ???????? ?????????? ??? ??? ??? ?? ??? whatever ???????? strap-??? ????????? ?? ???? ???? ?? ??? ?????? ??? ???? ?? ??? ?????????? ??? Windows NT ??????, ?? ?? ??? ??? ???? NTLDR ????? ?? ?????? ?? ?????, ?????? ??? ??? ?? ???????? ?? ?? ????? ?? ??????????? ????? ??? ???? ???-????? ?????? ?????, ?? ?? ?? ??? ?? ???????? ????? ?? ??????? ???? ??? ?????? ????? ?? ??????? ???? ?? ??? ?????? ??, "???-?????? ????? ?? ????? ??????" ????? ?? ?? ??????? ???? MS-DOS "??????" ?????? ?? ???????? ???? ??? ?? ?????? ????? ???????? ?????

???, ??? ?? ??? ?????? ??? ????? ?? ?????? ????? ??? hexidecimal ???: 0x55 0xAA.

?????? ??????

??? ???? ????? ?? ?? ???? FAT ??? ?????? ????? ??, ?? ?? several ????? ?? ?? ???? ??? ??? ???????? sense ????? ?? ??? ??? ???????? ????? ?? ???? ?? ???? ???? ?????? ?? ???, BytesPerSector 512 vast majority ?? ?????? ??? ???? ?????? ?? ??? ?????????? ??? ?????? ?? ??? ?? ???????? ????? ??? ??? ???????? ?????? ????? ?? ???????? ???? ?? ??? ??????? ????? ?? ??? ?? ??????? ?????

MS-DOS ?????? ???????? FAT ??????? ?? ??????? ??? ?????????? ????? ???: "?????? ?????? ?????."; "????? i/O ??????."; "????? ?????, ?? ???? ??? ??? ?? ?????";"???-?????? ????? ?? ????? ??????";"????? ?? ????? ?? ??? ?? ????? ????? ?????."; ?? "????? ??? ??????." Windows NT ?????? ???????? FAT ??????? ?? ??? ?????????? ????? ???: "???: ?????? Couldn't NTLDR."; "i/O ?????? ??? ?????."; ?? "????? ???? ???? ????? ???????? ????." ?? all-inclusive ???? ?? ??? ??? ?? ???? regard ???? ???? ?????? ??? ?? ??? ?????? ??? ???? ????? ????? ??, ?? ???? necessarily ????? ?? ??? ?????? ?? ??? ??? ?????? ??? MS-DOS ?? Windows NT ?? ????? ??????? ??? ???? ??? ???????? ???? ?? ????? ????? ?????????? ???-??? ????? ?? ????? ???, ??? ???? ??? ??? whatsoever, ?? ??? ??? ?????? ???? ??????? MS-DOS ?? Windows NT ???? ?? ???, ???? ????? ????? ??????? ?? ???? ??? ?????? ?? ???? ?? ???? ??? ???? ??? ???????? ???? ????? ?????? ?? ?? ??? ???? ?????? ?? ???? ????? ?? ???? ?? ???? ??? ?? ????? ???

??? ?????? ????? ?? ???????? ?? ???? ??? ?? ?? ?? ???????????? ???? ?? ??? ????? ?? ???? ?????????? ????-????? ????????? ?? ????? ???? ?? ??? ??????? ??? ???? ?? ????? ???? ???? ???? ?? ??? ??? ?????? ????? ?? ???? ???? ???? ????, ????? ??? ?????? ?? ???????? ????? ???????? ???? ??, ?? ?? ???? ???? ??? ?? ??? ????? ?? ??? ??? ?? ??? ?????? ??? ?? ???? ?? ???? ?????? ?? ????? ???

??? ???? ????? ?? ?? ?? ??? ???? ?? ??? ??? ?????? ?? ??????????? ???? ??? ??, ?? ????? ?? ?????????? ????? ????????????? ????? ?? ????? ???? ?? ??? ??????? ??? While it may be possible to recover from boot sector damage without resorting to reformatting the drive by manually modifying the fields described above, manual editing of boot sectors should only be attempted as a last resort and cannot be guaranteed to work in situations where other disk structures may also have been damaged.