Author Topic: Low-level Disk Access  (Read 13846 times)

MichaelW

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Low-level Disk Access
« on: July 15, 2012, 08:01:12 AM »
This was posted to the previous forum some time in 2009. It displays a hex-ascii dump of the MBR, and then if the first partition is bootable a dump of the volume boot sector. Note that I tested only on FAT32.
Well Microsoft, here’s another nice mess you’ve gotten us into.

hutch--

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Re: Low-level Disk Access
« Reply #1 on: July 16, 2012, 03:50:08 PM »
Seems to work on my NTFS partitions fine.

Code: [Select]

Read 512 bytes

00000000  33 C0 8E D0 BC 00 7C FB - 50 07 50 1F FC BE 1B 7C   3.....|.P.P....|
00000010  BF 1B 06 50 57 B9 E5 01 - F3 A4 CB BD BE 07 B1 04   ...PW...........
00000020  38 6E 00 7C 09 75 13 83 - C5 10 E2 F4 CD 18 8B F5   8n.|.u..........
00000030  83 C6 10 49 74 19 38 2C - 74 F6 A0 B5 07 B4 07 8B   ...It.8,t.......
00000040  F0 AC 3C 00 74 FC BB 07 - 00 B4 0E CD 10 EB F2 88   ..<.t...........
00000050  4E 10 E8 46 00 73 2A FE - 46 10 80 7E 04 0B 74 0B   N..F.s*.F..~..t.
00000060  80 7E 04 0C 74 05 A0 B6 - 07 75 D2 80 46 02 06 83   .~..t....u..F...
00000070  46 08 06 83 56 0A 00 E8 - 21 00 73 05 A0 B6 07 EB   F...V...!.s.....
00000080  BC 81 3E FE 7D 55 AA 74 - 0B 80 7E 10 00 74 C8 A0   ..>.}U.t..~..t..
00000090  B7 07 EB A9 8B FC 1E 57 - 8B F5 CB BF 05 00 8A 56   .......W.......V
000000A0  00 B4 08 CD 13 72 23 8A - C1 24 3F 98 8A DE 8A FC   .....r#..$?.....
000000B0  43 F7 E3 8B D1 86 D6 B1 - 06 D2 EE 42 F7 E2 39 56   C..........B..9V
000000C0  0A 77 23 72 05 39 46 08 - 73 1C B8 01 02 BB 00 7C   .w#r.9F.s......|
000000D0  8B 4E 02 8B 56 00 CD 13 - 73 51 4F 74 4E 32 E4 8A   .N..V...sQOtN2..
000000E0  56 00 CD 13 EB E4 8A 56 - 00 60 BB AA 55 B4 41 CD   V......V.`..U.A.
000000F0  13 72 36 81 FB 55 AA 75 - 30 F6 C1 01 74 2B 61 60   .r6..U.u0...t+a`
00000100  6A 00 6A 00 FF 76 0A FF - 76 08 6A 00 68 00 7C 6A   j.j..v..v.j.h.|j
00000110  01 6A 10 B4 42 8B F4 CD - 13 61 61 73 0E 4F 74 0B   .j..B....aas.Ot.
00000120  32 E4 8A 56 00 CD 13 EB - D6 61 F9 C3 49 6E 76 61   2..V.....a..Inva
00000130  6C 69 64 20 70 61 72 74 - 69 74 69 6F 6E 20 74 61   lid partition ta
00000140  62 6C 65 00 45 72 72 6F - 72 20 6C 6F 61 64 69 6E   ble.Error loadin
00000150  67 20 6F 70 65 72 61 74 - 69 6E 67 20 73 79 73 74   g operating syst
00000160  65 6D 00 4D 69 73 73 69 - 6E 67 20 6F 70 65 72 61   em.Missing opera
00000170  74 69 6E 67 20 73 79 73 - 74 65 6D 00 00 00 00 00   ting system.....
00000180  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00   ................
00000190  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00   ................
000001A0  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00   ................
000001B0  00 00 00 00 00 2C 44 63 - FE EE FE EE 00 00 80 01   .....,Dc........
000001C0  01 00 07 FE FF FF 3F 00 - 00 00 81 06 1C 1D 00 00   ......?.........
000001D0  C1 FF 05 FE FF FF C0 06 - 1C 1D 01 53 54 57 00 00   ...........STW..
000001E0  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00   ................
000001F0  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 55 AA   ..............U.

Read 512 bytes

00000000  EB 52 90 4E 54 46 53 20 - 20 20 20 00 02 08 00 00   .R.NTFS    .....
00000010  00 00 00 00 00 F8 00 00 - 3F 00 FF 00 3F 00 00 00   ........?...?...
00000020  00 00 00 00 80 00 80 00 - 80 06 1C 1D 00 00 00 00   ................
00000030  CA 01 08 00 00 00 00 00 - 51 72 20 00 00 00 00 00   ........Qr .....
00000040  F6 00 00 00 01 00 00 00 - 4B 7B F4 1C C6 F4 1C FE   ........K{......
00000050  00 00 00 00 FA 33 C0 8E - D0 BC 00 7C FB B8 C0 07   .....3.....|....
00000060  8E D8 E8 16 00 B8 00 0D - 8E C0 33 DB C6 06 0E 00   ..........3.....
00000070  10 E8 53 00 68 00 0D 68 - 6A 02 CB 8A 16 24 00 B4   ..S.h..hj....$..
00000080  08 CD 13 73 05 B9 FF FF - 8A F1 66 0F B6 C6 40 66   ...s......f...@f
00000090  0F B6 D1 80 E2 3F F7 E2 - 86 CD C0 ED 06 41 66 0F   .....?.......Af.
000000A0  B7 C9 66 F7 E1 66 A3 20 - 00 C3 B4 41 BB AA 55 8A   ..f..f. ...A..U.
000000B0  16 24 00 CD 13 72 0F 81 - FB 55 AA 75 09 F6 C1 01   .$...r...U.u....
000000C0  74 04 FE 06 14 00 C3 66 - 60 1E 06 66 A1 10 00 66   t......f`..f...f
000000D0  03 06 1C 00 66 3B 06 20 - 00 0F 82 3A 00 1E 66 6A   ....f;. ...:..fj
000000E0  00 66 50 06 53 66 68 10 - 00 01 00 80 3E 14 00 00   .fP.Sfh.....>...
000000F0  0F 85 0C 00 E8 B3 FF 80 - 3E 14 00 00 0F 84 61 00   ........>.....a.
00000100  B4 42 8A 16 24 00 16 1F - 8B F4 CD 13 66 58 5B 07   .B..$.......fX[.
00000110  66 58 66 58 1F EB 2D 66 - 33 D2 66 0F B7 0E 18 00   fXfX..-f3.f.....
00000120  66 F7 F1 FE C2 8A CA 66 - 8B D0 66 C1 EA 10 F7 36   f......f..f....6
00000130  1A 00 86 D6 8A 16 24 00 - 8A E8 C0 E4 06 0A CC B8   ......$.........
00000140  01 02 CD 13 0F 82 19 00 - 8C C0 05 20 00 8E C0 66   ........... ...f
00000150  FF 06 10 00 FF 0E 0E 00 - 0F 85 6F FF 07 1F 66 61   ..........o...fa
00000160  C3 A0 F8 01 E8 09 00 A0 - FB 01 E8 03 00 FB EB FE   ................
00000170  B4 01 8B F0 AC 3C 00 74 - 09 B4 0E BB 07 00 CD 10   .....<.t........
00000180  EB F2 C3 0D 0A 41 20 64 - 69 73 6B 20 72 65 61 64   .....A disk read
00000190  20 65 72 72 6F 72 20 6F - 63 63 75 72 72 65 64 00    error occurred.
000001A0  0D 0A 4E 54 4C 44 52 20 - 69 73 20 6D 69 73 73 69   ..NTLDR is missi
000001B0  6E 67 00 0D 0A 4E 54 4C - 44 52 20 69 73 20 63 6F   ng...NTLDR is co
000001C0  6D 70 72 65 73 73 65 64 - 00 0D 0A 50 72 65 73 73   mpressed...Press
000001D0  20 43 74 72 6C 2B 41 6C - 74 2B 44 65 6C 20 74 6F    Ctrl+Alt+Del to
000001E0  20 72 65 73 74 61 72 74 - 0D 0A 00 00 00 00 00 00    restart........
000001F0  00 00 00 00 00 00 00 00 - 83 A0 B3 C9 00 00 55 AA   ..............U.

Press any key to exit...
hutch at movsd dot com
http://www.masm32.com    :biggrin:  :skrewy:

ROBOSPOOK

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Re: Low-level Disk Access
« Reply #2 on: June 03, 2014, 03:40:38 AM »
Hutch,
  what op system are you running.. that looks like pre Vista/Win7 partition sector.. that's not the boot record which is at:
track 1 head 1 sector 1

Also Master Boot Record is a NORTONISM.. if you will a misnomer . MBR is only on a floppy look at and disassemble 
the very first sector on a floppy and you will see it is very very different than the very first sector of a hard disk.

Hard disks contains a partition table and jump code (this gets you to the boot record etc) on the very first sector.  The jump code points to the boor record which does the magic .. it tells us where things are.

On Vista and above things are a bit different and not like to old file system at all.

Robospook

ROBOSPOOK

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Re: Low-level Disk Access
« Reply #3 on: June 03, 2014, 04:04:55 AM »
I stand corrected that is exactly like my Win7 partition sector!  Well DUHHH  Anyhow.. this is a nice utility and exactly what I was looking for .. thanks guys.. well done!!

Robo

Gunther

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Re: Low-level Disk Access
« Reply #4 on: June 03, 2014, 05:22:32 AM »
Michael,

doesn't work with my Windows 7. The reason could be my EFI partition.

Code: [Select]
Zugriff verweigert

Press any key to exit...

Gunther
Get your facts first, and then you can distort them.

habran

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Re: Low-level Disk Access
« Reply #5 on: June 03, 2014, 05:46:33 AM »
It works on my machine with windows7
Code: [Select]
Read 512 bytes

00000000  33 C0 8E D0 BC 00 7C 8E - C0 8E D8 BE 00 7C BF 00   3.....|......|..
00000010  06 B9 00 02 FC F3 A4 50 - 68 1C 06 CB FB B9 04 00   .......Ph.......
00000020  BD BE 07 80 7E 00 00 7C - 0B 0F 85 10 01 83 C5 10   ....~..|........
00000030  E2 F1 CD 18 88 56 00 55 - C6 46 11 05 C6 46 10 00   .....V.U.F...F..
00000040  B4 41 BB AA 55 CD 13 5D - 72 0F 81 FB 55 AA 75 09   .A..U..]r...U.u.
00000050  F7 C1 01 00 74 03 FE 46 - 10 66 60 80 7E 10 00 74   ....t..F.f`.~..t
00000060  26 66 68 00 00 00 00 66 - FF 76 08 68 00 00 68 00   &fh....f.v.h..h.
00000070  7C 68 01 00 68 10 00 B4 - 42 8A 56 00 8B F4 CD 13   |h..h...B.V.....
00000080  9F 83 C4 10 9E EB 14 B8 - 01 02 BB 00 7C 8A 56 00   ............|.V.
00000090  8A 76 01 8A 4E 02 8A 6E - 03 CD 13 66 61 73 1E FE   .v..N..n...fas..
000000A0  4E 11 0F 85 0C 00 80 7E - 00 80 0F 84 8A 00 B2 80   N......~........
000000B0  EB 82 55 32 E4 8A 56 00 - CD 13 5D EB 9C 81 3E FE   ..U2..V...]...>.
000000C0  7D 55 AA 75 6E FF 76 00 - E8 8A 00 0F 85 15 00 B0   }U.un.v.........
000000D0  D1 E6 64 E8 7F 00 B0 DF - E6 60 E8 78 00 B0 FF E6   ..d......`.x....
000000E0  64 E8 71 00 B8 00 BB CD - 1A 66 23 C0 75 3B 66 81   d.q......f#.u;f.
000000F0  FB 54 43 50 41 75 32 81 - F9 02 01 72 2C 66 68 07   .TCPAu2....r,fh.
00000100  BB 00 00 66 68 00 02 00 - 00 66 68 08 00 00 00 66   ...fh....fh....f
00000110  53 66 53 66 55 66 68 00 - 00 00 00 66 68 00 7C 00   SfSfUfh....fh.|.
00000120  00 66 61 68 00 00 07 CD - 1A 5A 32 F6 EA 00 7C 00   .fah.....Z2...|.
00000130  00 CD 18 A0 B7 07 EB 08 - A0 B6 07 EB 03 A0 B5 07   ................
00000140  32 E4 05 00 07 8B F0 AC - 3C 00 74 FC BB 07 00 B4   2.......<.t.....
00000150  0E CD 10 EB F2 2B C9 E4 - 64 EB 00 24 02 E0 F8 24   .....+..d..$...$
00000160  02 C3 49 6E 76 61 6C 69 - 64 20 70 61 72 74 69 74   ..Invalid partit
00000170  69 6F 6E 20 74 61 62 6C - 65 00 45 72 72 6F 72 20   ion table.Error
00000180  6C 6F 61 64 69 6E 67 20 - 6F 70 65 72 61 74 69 6E   loading operatin
00000190  67 20 73 79 73 74 65 6D - 00 4D 69 73 73 69 6E 67   g system.Missing
000001A0  20 6F 70 65 72 61 74 69 - 6E 67 20 73 79 73 74 65    operating syste
000001B0  6D 00 00 00 00 00 00 00 - EF F6 92 FB 00 00 80 20   m..............
000001C0  21 00 27 59 1A BF 00 08 - 00 00 00 E0 2E 00 00 59   !.'Y...........Y
000001D0  1B BF 07 FE FF FF 00 E8 - 2E 00 00 80 AA 55 00 FE   .............U..
000001E0  FF FF 17 FE FF FF 00 68 - D9 55 00 F8 7A 01 00 00   .......h.U..z...
000001F0  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 55 AA   ..............U.

Read 512 bytes

00000000  EB 52 90 4E 54 46 53 20 - 20 20 20 00 02 08 00 00   .R.NTFS    .....
00000010  00 00 00 00 00 F8 00 00 - 3F 00 FF 00 00 08 00 00   ........?.......
00000020  00 00 00 00 80 00 80 00 - FF DF 2E 00 00 00 00 00   ................
00000030  00 F4 01 00 00 00 00 00 - 02 00 00 00 00 00 00 00   ................
00000040  F6 00 00 00 01 00 00 00 - 6C 99 14 62 9C 14 62 C0   ........l..b..b.
00000050  00 00 00 00 FA 33 C0 8E - D0 BC 00 7C FB 68 C0 07   .....3.....|.h..
00000060  1F 1E 68 66 00 CB 88 16 - 0E 00 66 81 3E 03 00 4E   ..hf......f.>..N
00000070  54 46 53 75 15 B4 41 BB - AA 55 CD 13 72 0C 81 FB   TFSu..A..U..r...
00000080  55 AA 75 06 F7 C1 01 00 - 75 03 E9 DD 00 1E 83 EC   U.u.....u.......
00000090  18 68 1A 00 B4 48 8A 16 - 0E 00 8B F4 16 1F CD 13   .h...H..........
000000A0  9F 83 C4 18 9E 58 1F 72 - E1 3B 06 0B 00 75 DB A3   .....X.r.;...u..
000000B0  0F 00 C1 2E 0F 00 04 1E - 5A 33 DB B9 00 20 2B C8   ........Z3... +.
000000C0  66 FF 06 11 00 03 16 0F - 00 8E C2 FF 06 16 00 E8   f...............
000000D0  4B 00 2B C8 77 EF B8 00 - BB CD 1A 66 23 C0 75 2D   K.+.w......f#.u-
000000E0  66 81 FB 54 43 50 41 75 - 24 81 F9 02 01 72 1E 16   f..TCPAu$....r..
000000F0  68 07 BB 16 68 70 0E 16 - 68 09 00 66 53 66 53 66   h...hp..h..fSfSf
00000100  55 16 16 16 68 B8 01 66 - 61 0E 07 CD 1A 33 C0 BF   U...h..fa....3..
00000110  28 10 B9 D8 0F FC F3 AA - E9 5F 01 90 90 66 60 1E   (........_...f`.
00000120  06 66 A1 11 00 66 03 06 - 1C 00 1E 66 68 00 00 00   .f...f.....fh...
00000130  00 66 50 06 53 68 01 00 - 68 10 00 B4 42 8A 16 0E   .fP.Sh..h...B...
00000140  00 16 1F 8B F4 CD 13 66 - 59 5B 5A 66 59 66 59 1F   .......fY[ZfYfY.
00000150  0F 82 16 00 66 FF 06 11 - 00 03 16 0F 00 8E C2 FF   ....f...........
00000160  0E 16 00 75 BC 07 1F 66 - 61 C3 A0 F8 01 E8 09 00   ...u...fa.......
00000170  A0 FB 01 E8 03 00 F4 EB - FD B4 01 8B F0 AC 3C 00   ..............<.
00000180  74 09 B4 0E BB 07 00 CD - 10 EB F2 C3 0D 0A 41 20   t.............A
00000190  64 69 73 6B 20 72 65 61 - 64 20 65 72 72 6F 72 20   disk read error
000001A0  6F 63 63 75 72 72 65 64 - 00 0D 0A 42 4F 4F 54 4D   occurred...BOOTM
000001B0  47 52 20 69 73 20 6D 69 - 73 73 69 6E 67 00 0D 0A   GR is missing...
000001C0  42 4F 4F 54 4D 47 52 20 - 69 73 20 63 6F 6D 70 72   BOOTMGR is compr
000001D0  65 73 73 65 64 00 0D 0A - 50 72 65 73 73 20 43 74   essed...Press Ct
000001E0  72 6C 2B 41 6C 74 2B 44 - 65 6C 20 74 6F 20 72 65   rl+Alt+Del to re
000001F0  73 74 61 72 74 0D 0A 00 - 8C A9 BE D6 00 00 55 AA   start.........U.

Press any key to exit...
Cod-Father

Gunther

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Re: Low-level Disk Access
« Reply #6 on: June 03, 2014, 05:49:51 PM »
It works on my machine with windows7

You're a lucky one and don't have an EFI disk. What size has your hard disk?

Gunther
Get your facts first, and then you can distort them.

dedndave

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Re: Low-level Disk Access
« Reply #7 on: June 03, 2014, 07:24:35 PM »
Quote
Both GPT and MBR-partitioned disks can contain an EFI System partition

EFI and UEFI are new acronyms for me   :redface:
but, i have dealt with a couple GPT-formatted drives (GUID Partition Table)

in both cases, they were GPT, but "reverted" to MBR format when attempts were made to access them that way
the result was loss of everything, as i couldn't find a proper utility to fix the issue
someone's probably written a utility for it, by now

the scenario went something like this....
the drive is external, larger than 2 Tb (i think that's the MBR limit)
connected to a Windows 7 computer USB port - all went well

now, the drive is connected to an XP machine
bang - they didn't have a GPT driver installed
so, it gets partially reformatted as MBR (simplified explanation)

habran

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Re: Low-level Disk Access
« Reply #8 on: June 03, 2014, 07:50:57 PM »
I have 2 discs on my laptop (Toshiba Qosmio)
C disc is 685 GB  ;faster one
D disc is 931 GB
Cod-Father

FORTRANS

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Re: Low-level Disk Access
« Reply #9 on: June 03, 2014, 10:16:43 PM »
Hi,

   Dual boot system with Boot Manager.

Steve

Code: [Select]
Read 512 bytes

00000000  FA B8 30 00 8E D0 BC 00 - 01 FB FC B8 00 00 8E D8   ..0.............
00000010  8E C0 BE 00 7C BF 00 7E - B9 00 02 F3 A5 B8 22 7E   ....|..~......"~
00000020  50 C3 BE CF 7E BB BE 7F - 80 7F 04 0A 74 45 83 C3   P...~.......tE..
00000030  10 81 FB FE 7F 7C F1 B8 - 00 00 CD 13 B8 00 08 B2   .....|..........
00000040  81 CD 13 72 2E B9 B4 7F - B2 81 E8 39 01 80 FC 00   ...r.......9....
00000050  75 21 26 81 3E FE 7D 55 - AA 75 18 BB BE 7D 80 7F   u!&.>.}U.u...}..
00000060  04 0A 75 06 B2 81 8B CB - EB 31 83 C3 10 81 FB FE   ..u......1......
00000070  7D 7C EB BB BE 7F 33 C9 - 80 3F 80 75 08 0B C9 75   }|....3..?.u...u
00000080  3C 8B CB EB 05 80 3F 00 - 75 33 83 C3 10 81 FB FE   <.....?.u3......
00000090  7F 7C E5 0B C9 75 02 CD - 18 B2 80 52 51 E8 E6 00   .|...u.....RQ...
000000A0  80 FC 00 74 05 BE 0A 7F - EB 13 BE 4C 7F 26 81 3E   ...t.......L.&.>
000000B0  FE 7F 55 AA 75 07 5E 5A - EA 00 7C 00 00 33 DB EB   ..U.u.^Z..|..3..
000000C0  02 CD 10 B4 0E AC 0A C0 - 75 F7 FB EB FE 38 00 54   ........u....8.T
000000D0  68 65 20 70 61 72 74 69 - 74 69 6F 6E 20 74 61 62   he partition tab
000000E0  6C 65 20 6F 6E 20 74 68 - 65 20 73 74 61 72 74 75   le on the startu
000000F0  70 20 64 72 69 76 65 20 - 69 73 20 69 6E 63 6F 72   p drive is incor
00000100  72 65 63 74 2E 0D 0A 00 - 3F 00 54 68 65 20 6F 70   rect....?.The op
00000110  65 72 61 74 69 6E 67 20 - 73 79 73 74 65 6D 20 63   erating system c
00000120  61 6E 6E 6F 74 20 62 65 - 20 6C 6F 61 64 65 64 20   annot be loaded
00000130  66 72 6F 6D 20 74 68 65 - 20 73 74 61 72 74 75 70   from the startup
00000140  20 64 72 69 76 65 2E 0D - 0A 00 39 00 54 68 65 20    drive....9.The
00000150  6F 70 65 72 61 74 69 6E - 67 20 73 79 73 74 65 6D   operating system
00000160  20 69 73 20 6D 69 73 73 - 69 6E 67 20 66 72 6F 6D    is missing from
00000170  20 74 68 65 20 73 74 61 - 72 74 75 70 20 64 72 69    the startup dri
00000180  76 65 2E 0D 0A 00 8B D9 - 8B 4F 02 8A 77 01 BB 00   ve.......O..w...
00000190  7C BF 05 00 B8 00 00 CD - 13 B8 01 02 CD 13 73 03   |.............s.
000001A0  4F 7F F1 C3 00 00 00 00 - 00 00 00 00 00 00 00 00   O...............
000001B0  00 00 00 00 00 00 01 00 - 57 E5 57 E5 33 CC 00 01   ........W.W.3...
000001C0  01 01 07 FE 3F FF 00 3F - 00 00 00 82 3E 00 00 00   ....?..?....>...
000001D0  41 FF 05 FE BF FD 3F 43 - 7D 00 3F 82 3E 00 80 01   A.....?C}.?.>...
000001E0  01 00 0A FE 3F 00 3F 00 - 00 00 82 3E 00 00 00 00   ....?.?....>....
000001F0  41 00 17 FE 7F FE 00 C1 - 3E 00 3F 82 3E 00 55 AA   A.......>.?.>.U.

Press any key to exit...

Gunther

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Re: Low-level Disk Access
« Reply #10 on: June 04, 2014, 03:03:27 AM »
I have 2 discs on my laptop (Toshiba Qosmio)
C disc is 685 GB  ;faster one
D disc is 931 GB

Good for you. If one of the disc would be grather than 1.2 TB, EFI is a must.

Gunther
Get your facts first, and then you can distort them.

Gunther

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Re: Low-level Disk Access
« Reply #11 on: June 04, 2014, 06:37:00 AM »
Here's the result from my old Win XP box:
Code: [Select]
Read 512 bytes

00000000  EB 63 90 D0 BC 00 7C FB - 50 07 50 1F FC BE 1B 7C   .c....|.P.P....|
00000010  BF 1B 06 50 57 B9 E5 01 - F3 A4 CB BD BE 07 B1 04   ...PW...........
00000020  38 6E 00 7C 09 75 13 83 - C5 10 E2 F4 CD 18 8B F5   8n.|.u..........
00000030  83 C6 10 49 74 19 38 2C - 74 F6 A0 B5 07 B4 03 02   ...It.8,t.......
00000040  FF 00 00 20 01 00 00 00 - 00 02 FA 90 90 F6 C2 80   ... ............
00000050  75 02 B2 80 EA 59 7C 00 - 00 31 00 80 01 00 00 00   u....Y|..1......
00000060  00 00 00 00 FF FA 90 90 - F6 C2 80 74 05 F6 C2 70   ...........t...p
00000070  74 02 B2 80 EA 79 7C 00 - 00 31 C0 8E D8 8E D0 BC   t....y|..1......
00000080  00 20 FB A0 64 7C 3C FF - 74 02 88 C2 52 BB 17 04   . ..d|<.t...R...
00000090  80 27 03 74 06 BE 88 7D - E8 17 01 BE 05 7C B4 41   .'.t...}.....|.A
000000A0  BB AA 55 CD 13 5A 52 72 - 3D 81 FB 55 AA 75 37 83   ..U..ZRr=..U.u7.
000000B0  E1 01 74 32 31 C0 89 44 - 04 40 88 44 FF 89 44 02   ..t21..D.@.D..D.
000000C0  C7 04 10 00 66 8B 1E 5C - 7C 66 89 5C 08 66 8B 1E   ....f..\|f.\.f..
000000D0  60 7C 66 89 5C 0C C7 44 - 06 00 70 B4 42 CD 13 72   `|f.\..D..p.B..r
000000E0  05 BB 00 70 EB 76 B4 08 - CD 13 73 0D F6 C2 80 0F   ...p.v....s.....
000000F0  84 D0 00 BE 93 7D E9 82 - 00 66 0F B6 C6 88 64 FF   .....}...f....d.
00000100  40 66 89 44 04 0F B6 D1 - C1 E2 02 88 E8 88 F4 40   @f.D...........@
00000110  89 44 08 0F B6 C2 C0 E8 - 02 66 89 04 66 A1 60 7C   .D.......f..f.`|
00000120  66 09 C0 75 4E 66 A1 5C - 7C 66 31 D2 66 F7 34 88   f..uNf.\|f1.f.4.
00000130  D1 31 D2 66 F7 74 04 3B - 44 08 7D 37 FE C1 88 C5   .1.f.t.;D.}7....
00000140  30 C0 C1 E8 02 08 C1 88 - D0 5A 88 C6 BB 00 70 8E   0........Z....p.
00000150  C3 31 DB B8 01 02 CD 13 - 72 1E 8C C3 60 1E B9 00   .1......r...`...
00000160  01 8E DB 31 F6 BF 00 80 - 8E C6 FC F3 A5 1F 61 FF   ...1..........a.
00000170  26 5A 7C BE 8E 7D EB 03 - BE 9D 7D E8 34 00 BE A2   &Z|..}....}.4...
00000180  7D E8 2E 00 CD 18 EB FE - 47 52 55 42 20 00 47 65   }.......GRUB .Ge
00000190  6F 6D 00 48 61 72 64 20 - 44 69 73 6B 00 52 65 61   om.Hard Disk.Rea
000001A0  64 00 20 45 72 72 6F 72 - 0D 0A 00 BB 01 00 B4 0E   d. Error........
000001B0  CD 10 AC 3C 00 75 F4 C3 - 29 8E 33 AC 00 00 80 01   ...<.u..).3.....
000001C0  01 00 07 FE FF FF 3F 00 - 00 00 37 16 71 02 00 FE   ......?...7.q...
000001D0  FF FF 0F FE FF FF B3 16 - 71 02 CE 2E AB 1A 00 00   ........q.......
000001E0  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 00 00   ................
000001F0  00 00 00 00 00 00 00 00 - 00 00 00 00 00 00 55 AA   ..............U.

Read 512 bytes

00000000  EB 52 90 4E 54 46 53 20 - 20 20 20 00 02 08 00 00   .R.NTFS    .....
00000010  00 00 00 00 00 F8 00 00 - 3F 00 FF 00 3F 00 00 00   ........?...?...
00000020  00 00 00 00 80 00 80 00 - 36 16 71 02 00 00 00 00   ........6.q.....
00000030  00 00 0C 00 00 00 00 00 - 63 11 27 00 00 00 00 00   ........c.'.....
00000040  F6 00 00 00 01 00 00 00 - 85 C1 C6 40 CF C6 40 CA   ...........@..@.
00000050  00 00 00 00 FA 33 C0 8E - D0 BC 00 7C FB B8 C0 07   .....3.....|....
00000060  8E D8 E8 16 00 B8 00 0D - 8E C0 33 DB C6 06 0E 00   ..........3.....
00000070  10 E8 53 00 68 00 0D 68 - 6A 02 CB 8A 16 24 00 B4   ..S.h..hj....$..
00000080  08 CD 13 73 05 B9 FF FF - 8A F1 66 0F B6 C6 40 66   ...s......f...@f
00000090  0F B6 D1 80 E2 3F F7 E2 - 86 CD C0 ED 06 41 66 0F   .....?.......Af.
000000A0  B7 C9 66 F7 E1 66 A3 20 - 00 C3 B4 41 BB AA 55 8A   ..f..f. ...A..U.
000000B0  16 24 00 CD 13 72 0F 81 - FB 55 AA 75 09 F6 C1 01   .$...r...U.u....
000000C0  74 04 FE 06 14 00 C3 66 - 60 1E 06 66 A1 10 00 66   t......f`..f...f
000000D0  03 06 1C 00 66 3B 06 20 - 00 0F 82 3A 00 1E 66 6A   ....f;. ...:..fj
000000E0  00 66 50 06 53 66 68 10 - 00 01 00 80 3E 14 00 00   .fP.Sfh.....>...
000000F0  0F 85 0C 00 E8 B3 FF 80 - 3E 14 00 00 0F 84 61 00   ........>.....a.
00000100  B4 42 8A 16 24 00 16 1F - 8B F4 CD 13 66 58 5B 07   .B..$.......fX[.
00000110  66 58 66 58 1F EB 2D 66 - 33 D2 66 0F B7 0E 18 00   fXfX..-f3.f.....
00000120  66 F7 F1 FE C2 8A CA 66 - 8B D0 66 C1 EA 10 F7 36   f......f..f....6
00000130  1A 00 86 D6 8A 16 24 00 - 8A E8 C0 E4 06 0A CC B8   ......$.........
00000140  01 02 CD 13 0F 82 19 00 - 8C C0 05 20 00 8E C0 66   ........... ...f
00000150  FF 06 10 00 FF 0E 0E 00 - 0F 85 6F FF 07 1F 66 61   ..........o...fa
00000160  C3 A0 F8 01 E8 09 00 A0 - FB 01 E8 03 00 FB EB FE   ................
00000170  B4 01 8B F0 AC 3C 00 74 - 09 B4 0E BB 07 00 CD 10   .....<.t........
00000180  EB F2 C3 0D 0A 46 65 68 - 6C 65 72 20 62 65 69 6D   .....Fehler beim
00000190  20 4C 65 73 65 6E 20 64 - 65 73 20 44 61 74 65 6E    Lesen des Daten
000001A0  74 72 84 67 65 72 73 00 - 0D 0A 4E 54 4C 44 52 20   tr.gers...NTLDR
000001B0  66 65 68 6C 74 00 0D 0A - 4E 54 4C 44 52 20 69 73   fehlt...NTLDR is
000001C0  74 20 6B 6F 6D 70 72 69 - 6D 69 65 72 74 00 0D 0A   t komprimiert...
000001D0  4E 65 75 73 74 61 72 74 - 20 6D 69 74 20 53 74 72   Neustart mit Str
000001E0  67 2B 41 6C 74 2B 45 6E - 74 66 0D 0A 00 00 00 00   g+Alt+Entf......
000001F0  00 00 00 00 00 00 00 00 - 83 A8 B6 CE 00 00 55 AA   ..............U.

Press any key to exit...

Gunther
Get your facts first, and then you can distort them.

MichaelW

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Re: Low-level Disk Access
« Reply #12 on: June 04, 2014, 07:03:36 AM »
Looking at the variation in MBR/boot sectors for the boot managers, it occurs to me to wonder if they routinely modify the sectors as part of their normal operation, and if they do what the effect on mean time to failure would be.
Well Microsoft, here’s another nice mess you’ve gotten us into.

FORTRANS

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Re: Low-level Disk Access
« Reply #13 on: June 04, 2014, 07:51:17 AM »
Looking at the variation in MBR/boot sectors for the boot managers, it occurs to me to wonder if they routinely modify the sectors as part of their normal operation, and if they do what the effect on mean time to failure would be.

Hi,

   Well, this one changes the identification byte for the partition
to identify which one will boot.  I don't know where other information
is stored.  But it should have a list of disks to boot and a time out
for user selection of the boot partition.

Regards,

Steve N.

sinsi

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Re: Low-level Disk Access
« Reply #14 on: June 04, 2014, 08:36:49 AM »
Looking at the variation in MBR/boot sectors for the boot managers, it occurs to me to wonder if they routinely modify the sectors as part of their normal operation, and if they do what the effect on mean time to failure would be.
I would imagine that changing bytes in the mbr once per boot would be less stressful than all the reading/writing that happens in a normal OS session.