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> X-Mailer: Juno 4.0.11 MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Juno-Line-Breaks: 0-9,11,13,15,17,19,21,23-27,29,31,33,35,37,39,41-45,47,49,51,53,55,57,59-63,65,67,69,71,73,75,77-141,143-172 X-Juno-Att: 0 X-Juno-RefParts: 0 From: Robert W Moss 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" ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj.