Помогите разобраться с boot-record и mbr (формат)!

Пожалуйста, помогите разобраться с boot-record, я имею ввиду с форматом: какой байт за что отвечает, что будет если его поменять... ну и т.д., т.е. все что с ним связано
можно семплы на turbo-asm. всем заранее прзнателен!! ???

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Сообщение отредактировано: Zzzaraza - 06.04.02, 06:07

Format of hard disk master boot sector:
Offset  Size    Description     (Table 00650)
00h 446 BYTEs  Master bootstrap loader code
1BEh 16 BYTEs   partition record for partition 1 (see #00651)
1CEh 16 BYTEs   partition record for partition 2
1DEh 16 BYTEs   partition record for partition 3
1EEh 16 BYTEs   partition record for partition 4
1FEh    WORD    signature, AA55h indicates valid boot block

Format of partition record:
Offset  Size    Description     (Table 00651)
00h    BYTE    boot indicator (80h = active partition)
01h    BYTE    partition start head
02h    BYTE    partition start sector (bits 0-5)
03h    BYTE    partition start track (bits 8,9 in bits 6,7 of sector)
04h    BYTE    operating system indicator (see #00652)
05h    BYTE    partition end head
06h    BYTE    partition end sector (bits 0-5)
07h    BYTE    partition end track (bits 8,9 in bits 6,7 of sector)
08h    DWORD   sectors preceding partition
0Ch    DWORD   length of partition in sectors
SeeAlso: #00650

(Table 00652)
Values for operating system indicator:
00h    empty partition-table entry
01h    DOS 12-bit FAT
02h    XENIX root file system
03h    XENIX /usr file system (obsolete)
04h    DOS 16-bit FAT (up to 32M)
05h    DOS 3.3+ extended partition
06h    DOS 3.31+ Large File System (16-bit FAT, over 32M)
07h    QNX
07h    OS/2 HPFS
07h    Windows NT NTFS
07h    Advanced Unix
07h    see partition boot record; could be any of the above or others
08h    OS/2 (v1.0-1.3 only)
08h    AIX bootable partition, SplitDrive
08h    Commodore DOS
08h    DELL partition spanning multiple drives
09h    AIX data partition
09h    Coherent filesystem
0Ah    OS/2 Boot Manager
0Ah    OPUS
0Ah    Coherent swap partition
0Bh    Windows95 with 32-bit FAT
0Ch    Windows95 with 32-bit FAT (using LBA-mode INT 13 extensions)
0Eh    logical-block-addressable VFAT (same as 06h but using LBA-mode INT 13)
0Fh    logical-block-addressable VFAT (same as 05h but using LBA-mode INT 13)
10h    OPUS
11h    OS/2 Boot Manager hidden 12-bit FAT partition
12h    Compaq Diagnostics partition
14h    (resulted from using Novell DOS 7.0 FDISK to delete Linux Native part)
14h    OS/2 Boot Manager hidden sub-32M 16-bit FAT partition
16h    OS/2 Boot Manager hidden over-32M 16-bit FAT partition
17h    OS/2 Boot Manager hidden HPFS partition
17h    hidden NTFS partition
18h    AST special Windows swap file ("Zero-Volt Suspend" partition)
19h    Willowtech Photon coS
1Bh    hidden Windows95 FAT32 partition
1Ch    hidden Windows95 FAT32 partition (using LBA-mode INT 13 extensions)
1Eh    hidden LBA VFAT partition
20h    Willowsoft Overture File System (OFS1)
21h    officially listed as reserved
21h    FSo2
23h    officially listed as reserved
24h    NEC MS-DOS 3.x
26h    officially listed as reserved
31h    officially listed as reserved
33h    officially listed as reserved
34h    officially listed as reserved
36h    officially listed as reserved
38h    Theos
3Ch    PowerQuest PartitionMagic recovery partition
40h    VENIX 80286
41h    Personal RISC Boot
41h    PowerPC boot partition
42h    SFS (Secure File System) by Peter Gutmann
45h    EUMEL/Elan
46h    EUMEL/Elan
47h    EUMEL/Elan
48h    EUMEL/Elan
4Fh    Oberon boot/data partition
50h    OnTrack Disk Manager, read-only partition
51h    OnTrack Disk Manager, read/write partition
51h    NOVELL
52h    CP/M
52h    Microport System V/386
53h    OnTrack Disk Manager, write-only partition???
54h    OnTrack Disk Manager (DDO)
55h    EZ-Drive (see also INT 13/AH=FFh"EZ-Drive")
56h    GoldenBow VFeature
5Ch    Priam EDISK
61h    SpeedStor
63h    Unix SysV/386, 386/ix
63h    Mach, MtXinu BSD 4.3 on Mach
63h    GNU HURD
64h    Novell NetWare 286
64h    SpeedStore
65h    Novell NetWare (3.11)
67h    Novell
68h    Novell
69h    Novell
70h    DiskSecure Multi-Boot
71h    officially listed as reserved
73h    officially listed as reserved
74h    officially listed as reserved
75h    PC/IX
76h    officially listed as reserved
7Eh    F.I.X.
80h    Minix v1.1 - 1.4a
81h    Minix v1.4b+
81h    Linux
81h    Mitac Advanced Disk Manager
82h    Linux Swap partition
82h    Prime
82h    Solaris (Unix)
83h    Linux native file system (ext2fs/xiafs)
84h    OS/2-renumbered type 04h partition (related to hiding DOS C: drive)
85h    Linux EXT
86h    FAT16 volume/stripe set (Windows NT)
87h    HPFS Fault-Tolerant mirrored partition
87h    NTFS volume/stripe set
93h    Amoeba file system
94h    Amoeba bad block table
98h    Datalight ROM-DOS SuperBoot
99h    Mylex EISA SCSI
A0h    Phoenix NoteBIOS Power Management "Save-to-Disk" partition
A1h    officially listed as reserved
A3h    officially listed as reserved
A4h    officially listed as reserved
A5h    FreeBSD, BSD/386
A6h    OpenBSD
A9h    NetBSD (http://www.netbsd.org/)
B1h    officially listed as reserved
B3h    officially listed as reserved
B4h    officially listed as reserved
B6h    officially listed as reserved
B6h    Windows NT mirror set (master), FAT16 file system
B7h    BSDI file system (secondarily swap)
B7h    Windows NT mirror set (master), NTFS file system
B8h    BSDI swap partition (secondarily file system)
BEh    Solaris boot partition
C0h    DR DOS/DR-DOS/Novell DOS secured partition
C0h    CTOS
C1h    DR DOS 6.0 LOGIN.EXE-secured 12-bit FAT partition
C4h    DR DOS 6.0 LOGIN.EXE-secured 16-bit FAT partition
C6h    DR DOS 6.0 LOGIN.EXE-secured Huge partition
C6h    corrupted FAT16 volume/stripe set (Windows NT)
C6h    Windows NT mirror set (slave), FAT16 file system
C7h    Syrinx Boot
C7h    corrupted NTFS volume/stripe set
C7h    Windows NT mirror set (slave), NTFS file system
CBh    Reserved for DR DOS/DR-DOS/OpenDOS secured FAT32
CCh    Reserved for DR DOS/DR-DOS secured FAT32 (LBA)
CEh    Reserved for DR DOS/DR-DOS secured FAT16 (LBA)
D0h    Multiuser DOS secured FAT12
D1h    Old Multiuser DOS secured FAT12
D4h    Old Multiuser DOS secured FAT16 (<= 32M)
D5h    Old Multiuser DOS secured extended partition
D6h    Old Multiuser DOS secured FAT16 (> 32M)
D8h    CP/M-86
DBh    CP/M, Concurrent CP/M, Concurrent DOS
DBh    CTOS (Convergent Technologies OS)
E1h    SpeedStor 12-bit FAT extended partition
E2h    DOS read-only (Florian Painke's XFDISK 1.0.4)
E3h    DOS read-only
E3h    Storage Dimensions
E4h    SpeedStor 16-bit FAT extended partition
E5h    officially listed as reserved
E6h    officially listed as reserved
EBh    BeOS BFS (BFS1)
F1h    Storage Dimensions
F2h    DOS 3.3+ secondary partition
F3h    officially listed as reserved
F4h    SpeedStor
F4h    Storage Dimensions
F5h    Prologue
F6h    officially listed as reserved
FEh    LANstep
FEh    IBM PS/2 IML (Initial Microcode Load) partition
FFh    Xenix bad block table
Note:   for partition type 07h, one should inspect the partition boot record
         for the actual file system type
SeeAlso: #00651

2ZZZaraza
Можно на              cr@nk.inbox.as
или на       IIPUtBOPIIIuK@inbox.ru

2z:
Спаcибо, только она не работает и я не понимаю что вообще должна, т.к. написана не на Asm... ???

2 7in
Очень помогло! Теперь не мог бы ответить о формате просто boot-record'a  логического диска (не mbr!)?
Заранее признателен!

Это из TechHelp'а.....

The DOS boot sector of a floppy disk or a hard disk partition is expected
to be in this format.  Prior to DOS 4.0, a smaller structure was used (see
notes, below).

BootSectorRec
 Offset Size Contents
 ------ ---- -----------------------------------------------------
  +0      3  abJmpCode    JMP opcode to start of boot code
  +3      8  abOem        e.g., "MSDOS6.0" or "IBM  4.0"
 +0bH     2  wSectSize    bytes per sector (usually 512; 200H)
 +0dH     1  bClustSects  sectors per allocation unit (cluster)
 +0eH     2  wResSects    boot and reserved sectors
 +10H     1  bFatCnt      number of File Allocation Tables.  See FAT.
 +11H     2  wRootEntries max number of 32-byte DirEntryRecs in root
 +13H     2  wTotSects    total number of sectors in media
                          0000H means >32 MB, so use lBigTotSects
+15H      1  bMedia       media descriptor (same as 1st byte in FAT)
+16H      2  wFatSects    number of sectors in one FAT
+18H      2  wSectsPerTrk sectors per track
+1aH      2  wHeads       number of read/write heads
+1cH      4  lHidSects    hidden sectors (ignore hiword in pre-DOS 4.0)
+20H      4  lBigTotSects 32-bit TotSects in volume (partitions > 32M)

+24H      1  bDrvNo       80H=first hard disk (used internally by DOS)
+25H      1  res1         (reserved)
+26H      1  bExtBootSig  Extended boot record signature (always 29H)
+27H      4  lSerNo       Volume Serial Number (based on when formatted)
+2bH     11  abVolLabel   Volume Label (11-character, blank padded)
+36H      8  abFileSysID  contains 'FAT12   ' or 'FAT16   ')
         62               length of formatted portion of BootSectorRec

+3eH      ?  abBootCode   code and data that performs disk bootstrap
+2ffH                      end of boot sector

See BPBRec for a description of most of these fields.  Fields unique to
the BootSectorRec include:

  abJmpCode  Since the Boot Sector is used as program code during system
             startup, the first bytes in the sector are a JMP opcode to get
             past the data area.  It usually jumps to abBootCode.

      abOem  This is an 8-character text field that is supposed to contain
             the signature of the version of DOS which formatted the disk
             (or otherwise laid down the boot sector).  It is not used by
             DOS.

     bDrvNo  On the first hard disk in a system, this field contains 80H.
             Otherwise it should be 00H.  Used internally by DOS.

bExtBootSig  Prior to DOS 4.0, the formatted portion of the Boot Sector
             ended at offset 1eH and that variation is still supported.
             Boot Sectors which contain 29H in this field (offset 26H) are
             expected to contain the entire 3eH-byte record.

     lSerNo  a 32-bit volume serial number.  It is based on the time and
             date when formatted, making the disk unique for the system
             which formatted it.  This field is used by block device
             drivers which support Removable Media and Change Line
             functions (see Device Requests and fn 44H).

             On disks formatted by DOS versions prior to 4.0, there is no
             lSerNo or abVolLabel fields.  On pre-formatted diskettes,
             these fields are often non-unique.  In either case, DOS might
             not be able to detect a disk swap.

 abVolLabel  the 11-character, blank-padded, volume label.  DOS lays this
             down when the disk is formatted AND DOS updates it (along with
             the volume label entry in the root directory) when you use the
             Label command.

abFileSysID  this 8-character, blank-padded text field identifies the file
             system.  It can be 'FAT12   ' (12-bit FAT entries) or
             'FAT16   ' (16-bit FAT entries).  See File Allocation Table.

 abBootCode  this is the start of the unformatted portion of the boot
             sector.  It contains data and code that is executed when the
             disk is booted.

Versions: * DOS 2.x: the formatted part of the record ended at offset 18H.
         * DOS 3.x: the formatted part of the record ended at offset 1eH.
         * DOS 4.0+: bExtBootSig contains 29H and all fields through
           offset 3eH are used.

  Notes: * Use absolute disk read INT 25H (DX=0) to read this sector OR
           - floppy disks: The boot sector is at BIOS INT 13H  head 0,
             track 0, sector 1
           - hard disks: read the Partition Table to determine BIOS Head,
             Track, Sector to seek before using INT 13H.

         * To convert a cluster number (as read from the wClustNo field of
           a Directory Entry or a FAT chain) into a absolute sector number
           (as used in INT 25H/26H calls), you may use DOS Fn 32H or read
           the Boot Sector and apply the formulae:

             wRootSects = (wRootEntries * 32) / wSectSize
             wFirstData = wResSects + (wFatSects * bFatCnt) + wRootSects
             lAbsSector = wFirstData + ((lAnyClusterNo - 2) * bClustects)

           Use the calculated value (lAbsSector) in INT 25H or INT 26H
           calls.

         * Very old hard disks which require an installed device driver
           (non-bootable hard disks) may contain garbage in the boot
           sector.  When possible, use DOS fns such as 32H to obtain
           information about the device.


А это немного об отличиях FAT32 от FAT16 (Boot-сектор тоже меняется).... из документации к прграмме Presizer (www.zeleps.com).....

  3.3 The Windows FAT32 filesystem structure

The FAT32 filesystem is quite similar to the FAT16 filesystem. The following
differences exist:

-FAT entries are now 32bit wide, allowing for a maximum of approximately 200
milion clusters in a single partition (actually, each FAT entry is 28bit wide,
the upper 4 bits are reserved for future use and must always be 0).
-The boot sector's information has been changed (see the table below)
-The root directory does not necessarily reside in the beginning of the drive
and it can grow to any size desirable.
-FAT mirroring can be disabled

In details, the boot sector entries are the following:

Offset            Description
0x03-0x0A         OEM ID: This is a small string written by the formatter.
0x0B-0x0C         Bytes per sector: This is always 512 (it depends on the
                 physical disks characteristics). If you have a disk with
                 a different value, please don't hesitate to inform me.
                 Partition Resizer WON'T WORK FOR DISKS WITH SECTOR SIZE
                 OTHER THAN 512!
0x0D              Sectors per Cluster: The cluster is the basic block of
                 information on a FAT drive. A FAT drive cannot have more
                 than 65527 clusters. This size can limit the maximum size
                 a partition can reach after resizing.
0x0E-0x0F         Reserved sectors at beginning: first FAT sector number
                 (0 based)
0x10              FAT copies: Number of FAT copies. Normally there
                 are two copies of FAT.
0x11-0x14         Reserved, must be 0.
0x15              Media descriptor byte: This byte is always F8 for hard
                 disks.
0x16-0x17         Reserved, must be 0
0x18-0x19         Sectors per track: Same as the physical disk's sectors per
                 track value.
0x1A-0x1B         Sides: Same as the physical disk's head number.
0x1C-0x1F         Special hidden sectors: This is how many sectors exist
                 between the partition's description sector and the boot
                 sector. Usually one track.
0x20-0x23         Big total number of sectors: If we have more than 65536
                 sectors in the partition, their number is written here.
0x24-0x27         Big Sectors per FAT value (old SPF value is now reserved).
0x28-0x29         Flags used for specifying FAT mirroring properties.
0x2A-0x2B         Major and minor version of the file system.
0x2C-0x2F         Root start: The first cluster (start) of the root directory.
0x30-0x31         File System sector number: offset of the file system sector
                 (see below).
0x32-0x33         Backup Boot Sector: offset of the backup copy of this
                 sector.
0x34-0x3F         Reserved.
0x40              Physical drive number: This is the physical drive number
                 (c:0x80, d:0x81 etc.).
0x41              Reserved.
0x42              Extended boot record signature: This marks an extended
                 boot record. If it is 29, the disk was formatted by DOS
                 4.0 or later.
0x43-0x46         Volume serial number: This is the partition's serial number.
0x47-0x51         Volume label: This is the partition's label string.
0x52-0x59         FS ID: This is a string that identifies a partition as
                 FAT32.

After this boot sector, the File System Sector exists, containing the
following information:

0x1E8-0x1EB       Free cluster count: contains the number of free clusters
                 in the drive (used to speed up free space calculation). If
                 it is -1 the value is recalculated.
0x1EC-0x1EF       First free cluster: number of the first available cluster
                 in the partition.

I will not go into more detailed explaination of the FAT32 file system. For
more information, please visit the Microsoft Developers Library at
http://www.microsoft.com/msdn and go to SDK Documentation - Platform SDK -
Windows Base Services - Windows 95 Features - Windows 95 Reference -
FAT32 API Reference - Structures.

2 7in огромное спасибо! очень помогло при написании куровой!