-=> Mocking Craig Hart to All <=-
   
 CH> I've run into one problem. I need to know how to decode the LOGICAL
 CH> drives in an Extended DOS partition. By decode I mean access the table
i'm not positive but i would expect that an extended partition would be
by and large the same as a regular partition... if so, the following may
be of some use to you...
 HelpPC 2.10           Quick Reference Utility     Copyright 1991 David 
Jurgens
             Disk Partition Table (Fixed disk boot record)
 
       Offset*    Represents:  (see format below)
 
        01BE*    Partition 1 data table  (16 bytes)
        01CE*    Partition 2 data table  (16 bytes)
        01DE*    Partition 3 data table  (16 bytes)
        01EE*    Partition 4 data table  (16 bytes)
        01FE*    Signature  (hex 55 AA, 2 bytes)
 
 *Offset from beginning of partition data shown above:
 
      Offset Size**Description
 
        00   byte   boot indicator
        01   byte   beginning sector head number
        02   byte   beginning sector (2 high bits of cylinder #)
        03   byte   beginning cylinder# (low order bits of cylinder #)
        04   byte   system indicator
        05   byte   ending sector head number
        06   byte   ending sector (2 high bits of cylinder #)
        07   byte   ending cylinder# (low order bits of cylinder #)
        08   dword  number of sectors preceding the partition
        0B   dword  number of sectors in the partition
 
 
 *Boot indicator (BYTE)
 
        00  - non-bootable partition
        80  - bootable partition (one partition only)
 
 
 *System Indicator (BYTE)
 
        00 - unknown operating system
        01 - DOS with 12 bit FAT, 16 bit sector number
        02 - XENIX
        04 - DOS with 16 bit FAT, 16 bit sector number
        05 - DOS Extended partition (DOS 3.3+)
        06 - DOS 4.0 (Compaq 3.31), 32 bit sector number
        51 - Ontrack extended partition
        64 - Novell
        75 - PCIX
        DB - CP/M
        FF - BBT
 
 
 *Signature
 
        Hex 55AA marks the end of valid boot sector.* This is also
        required in each of the partition boot records.
 
 
 *Sector/Cylinder
 
        2 bytes are combined to a word similar to INT 13:
 
        *7*6*5*4*3*2*1*0* 1st byte  (sector)
         * * ************* Sector offset within cylinder
         **************** High order bits of cylinder #
 
        *7*6*5*4*3*2*1*0* 2nd byte  (cylinder)
         ****************** Low order bits of cylinder #
 
 
        - all partitions begin on sector 1 head 0, except the first
          partition which follows the disk's master boot record and begins
          in sector 2
        - some of this information may vary with some variants of DOS 3.2
          and DOS 3.3 that use their own sectoring scheme for large disks
... in AV, the code the gets control first wins... boot clean!...
--- TGWave v1.20.b09
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