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| To: | opendos AT delorie DOT com |
| Date: | Thu, 2 Nov 2000 23:17:35 -0800 |
| Subject: | RE: FDISK |
| Message-ID: | <20001102.234025.-3964635.0.domanspc@juno.com> |
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| From: | Robert W Moss <domanspc AT juno DOT com> |
| Reply-To: | opendos AT delorie DOT com |
After the fdisk program there comes :
DOS DISK STRUCTURES AND LAYOUT
--
Master Boot Record (Partition Table)
--
Offset Length Description
--
Partition Table Entry #1
--
1BEh 446 1 byte Boot Indicator Byte (80h = Active, else 00h)
1BFh 447 1 byte Starting Head (or Side) of Partition
1C0h 448 16 bits Starting Cylinder (10 bits) and Sector (6 bits)
1C2h 450 1 byte System Indicator Byte (see table)
1C3h 451 1 byte Ending Head (or Side) of Partition
1C4h 452 16 bits Ending Cylinder (10 bits) and Sector (6 bits)
1C6h 454 1 dword Relative Sector Offset of Partition
1CAh 458 1 dword Total Number of Sectors in Partition
Partition Table Entry #2
--
1CEh 462 1 byte Boot Indicator Byte (80h = Active, else 00h)
1CFh 463 1 byte Starting Head (or Side) of Partition
1D0h 464 16 bits Starting Cylinder (10 bits) and Sector (6 bits)
1D3h 466 1 byte System Indicator Byte (see table)
1D3h 467 1 byte Ending Head (or Side) of Partition
1D4h 468 16 bits Ending Cylinder (10 bits) and Sector (6 bits)
1D6h 470 1 dword Relative Sector Offset of Partition
1DAh 474 1 dword Total Number of Sectors in Partition
Partition Table Entry #3
--
1DEh 478 1 byte Boot Indicator Byte (80h = Active, else 00h)
1DFh 479 1 byte Starting Head (or Side) of Partition
1E0h 480 16 bits Starting Cylinder (10 bits) and Sector (6 bits)
1E2h 482 1 byte System Indicator Byte (see table)
1E3h 483 1 byte Ending Head (or Side) of Partition
1E4h 484 16 bits Ending Cylinder (10 bits) and Sector (6 bits)
1E6h 486 1 dword Relative Sector Offset of Partition
1EAh 490 1 dword Total Number of Sectors in Partition
Partition Table Entry #4
--
1EEh 494 1 byte Boot Indicator Byte (80h = Active, else 00h)
1EFh 495 1 byte Starting Head (or Side) of Partition
1F0h 496 16 bits Starting Cylinder (10 bits) and Sector (6 bits)
1F2h 498 1 byte System Indicator Byte (see table)
1F3h 499 1 byte Ending Head (or Side) of Partition
1F4h 500 16 bits Ending Cylinder (10 bits) and Sector (6 bits)
1F6h 502 1 dword Relative Sector Offset of Partition
1FAh 506 1 dword Total Number of Sectors in Partition
Partition Table System Indicator Byte Values
--
Value Description
--
00h No partition allocated in this entry
01h Primary DOS, 12-bit FAT (Partitions < 16M)
04h Primary DOS, 16-bit FAT (16M <= Partition <= 32M)
05h Extended DOS (Points to next Primary Partition)
06h Peimary DOS, 16-bit FAT (Partition > 32M)
07h OS/2 HPFS Partition
02h MS-XENIX root Partition
03h MS-XENIX user Partition
08h AIX File System Partition
09h AIX Boot Partition
50h Ontrack Disk Manager READ-ONLY Partition
51h Ontrack Disk Manager READ-WRITE Partition
56h Golden Bow Vfeature Partition
61h Storage Dimensions Speedstor Partition
63h IBM 386/ix or UNIX System V/386 Partition
64h Novell Netware Partition
75h IBM PCIX Partion
DBh Digital Research Concurrent DOS/CPM-86 Partition
F2h Some OEM's DOS 3.2+ second partition
FFh UNIX Bad Block Table Partition
SIGNATURE BYTES
-------
1FEh 510 2 bytes Boot Sector Signature (55AAh)
---
A WORD equals two bytes which are read in reverse order,
and a DWORD equals two WORDS that are read in reverse order.
__________________
DOS BOOT RECORD
--
DOS Volume Boot Sector (DVB) Format
--
Offset Field
Hex Dec Length Description
-----
00h 0 3 bytes Jump Instruction to boot Program Code
03h 3 8 bytes OEM Name and DOS Version ("IBM 5.0")
0Bh 11 1 word Bytes/Sector (usually 512)
0Dh 13 1 byte Sectors/Cluster (must be a power of 2)
0Eh 14 1 word Reserved Sectors (Boot Sectors, usually 1)
10h 16 1 byte FAT Copies (usually 2)
11h 17 1 word Maximum Root Direcory Entries (usually 512)
13h 19 1 word Total Sectors (If Partition <= 32M, else 0)
15h 21 1 byte Media Descriptor Byte (F8h for hard disks)
16h 22 1 word Sectors/FAT
18h 24 1 word Sectors/Track
1Ah 26 1 word Number of Herads
1Ch 28 1 dword Hidden Sectors (If Partition <= 32M, 1 word only)
DOS 4.0 or Higher only (Others 00h)
-------
20h 32 1dword Total Sectors (If Partition > 32M, else 0)
24h 36 1 byte Physical Drive No. (00h=floppy, 80h=hard disk)
25h 37 1 byte Reserved (00h)
26h 38 1 byte Extended Boot Record Signature (29h)
(Another signature someone was looking for ,
maybe?)
27h 39 1 dword Volume Serial Number (32-bit random number)
2Bh 43 11 bytes Volume Label ("NO NAME" stored if no label)
36h 54 8 bytes File System ID ("FAT12" OR "fat16")
All Versions of DOS
------
3Eh 62 450 bytes Boot Program Code
1FEh 510 2 bytes Signature Bytes (55AAh)
----------
I hope none of you old timers is bored yet.
All of this H&P entry is killing my back and wrists.
I guess I am getting old, and I wonder how I used to do
touch typing for eight hours a day in the AF 30 years ago,
although my wrists are starting to remember.
Trivia question:
What was the first do something program run on an Altair 8080,
(SN #003), and what was the name of the score and the encore?
How was it accomplished?
BONUS POINTS: Where and when did it happen?
Who was the perpetrator?
BOB 'DOMAN' MOSS "Chocolate is a vitamin"
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