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Chasney913
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Joined: 28 Aug 2007
Posts: 117
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 Posted: 19 Dec 2007 03:37:46 pm Post subject: |
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So I'm on the computer (surprise, surprise) and suddenly some of my shortcuts stop working. I figure out it is one of my external hard drives. (X:/, in case you needed to know.) Now, I'm a bit concerned, because I keep most of my information on the X drive, and so I need it to work.
Whenever I go into Windows Explorer, it works fine, until I do something related to or on the drive. Then it crashes. So I restart, and the computer seems to be working fine, except it seems to think the X drive (not the internal C drive) is the master boot drive, where the desktop is. (No desktop operations, because it can't find the file.)
So I restart again, this time I turn off the external hard drives during the boot sequence. When I'm all logged in, I attempt to connect the X drive. However, it cannot load.
I go into the Disk Management, and it shows up, but it is not initialized. I initialize it. Finally I assign it a drive letter. Now, it still doesn't work, but because it thinks the drive is not formatted. I can't format it without losing all my stuff. (Not good.)
Sorry if that's too long.
Any help, questions or comments would be greatly appreciated |
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NETWizz
Byte by bit
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Joined: 20 May 2003
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| Posted: 19 Dec 2007 09:37:23 pm Post subject: |
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First get your data back.
Try something like testdisk to recovery your partition(s). If you cannot do that, try PhotoRec to recovery your data.
Once you rescue your data, then diagnose the drive and determine how bad it actually is. If all is well, you can just format it again and you will be good. |
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Chasney913
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Joined: 28 Aug 2007
Posts: 117
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| Posted: 19 Dec 2007 10:22:24 pm Post subject: |
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| Any suggestions on getting the data back? |
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NETWizz
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| Posted: 20 Dec 2007 12:15:06 am Post subject: |
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NETWizz wrote: Try something like testdisk to recovery your partition(s). If you cannot do that, try PhotoRec to recovery your data.
See Above |
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Newbie
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| Posted: 20 Dec 2007 03:45:45 pm Post subject: |
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Yeah, I looked at the programs mentioned by Netwizz and they look like they will suit your needs perfectly.
Why did you ask for more suggestions? Did you even try the two programs mentioned by Netwizz?
To get you started here you go:
http://en.wikipedia.org/wiki/TestDisk
http://en.wikipedia.org/wiki/PhotoRec
Last edited by Guest on 20 Dec 2007 03:47:07 pm; edited 1 time in total |
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NETWizz
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| Posted: 20 Dec 2007 08:09:49 pm Post subject: |
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They are both awesome. If you have previously deleted and recreated the partition and messed with it a lot, just delete the partition and jump right to Photo Rec. It will even work within Windows, and it is very easy to use.
All you need to know is your device name, type of file system, and simple stuff like that. |
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alexrudd
pm me if you read this
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Joined: 06 Oct 2004
Posts: 2335
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| Posted: 21 Dec 2007 12:00:52 am Post subject: |
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I think he read
1.) Get your data back.
2.) Use testdisk to recover ...
Wait how do I go to step 2 if I don't know how to do step 1? |
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JoostinOnline
Active Member
Joined: 22 Aug 2007
Posts: 559
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| Posted: 21 Dec 2007 11:33:48 am Post subject: |
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| I am curious as to what is wrong with your drive. Would you mind posting your OS and what file system your drive is formated as? |
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Newbie
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| Posted: 21 Dec 2007 12:45:34 pm Post subject: |
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alexrudd wrote: I think he read
1.) Get your data back.
2.) Use testdisk to recover ...
Wait how do I go to step 2 if I don't know how to do step 1?
[post="117581"]<{POST_SNAPBACK}>[/post]
It's not a list of directions. You don't have to use 1 and 2 sequentially. You use which ever you find better. NetWizz did say " If you cannot do that, try PhotoRec to recovery your data" so you don't need to have used one before the other. |
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Chasney913
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Joined: 28 Aug 2007
Posts: 117
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| Posted: 21 Dec 2007 04:14:07 pm Post subject: |
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Well, I am using Windows, and I'll try to provide as much information about the drive I know.
200 GB
NTFS
External, using USB
Maxtor
Not too much there, I know. However, I am running R-Studio right now. I says that it can only recover about 50 GB of about 150 GB used, and the files are incorrect, because I don't have any .mpg files, but it says I have tens of thousands, each a couple seconds long.
It would be nice to get the data back, so I may try PhotoRec once R-Studio finishes running (maybe about a day or so), because it seems not to know the data.
I'm not too great with the drive information though, and PhotoRec seems to need information about the drive, plus I had R-Studio (forgot about it, though, that's why I didn't mention it.) If R-Studio doesn't work, I'll try PhotoRec.
EDIT: Also, PhotoRec bases drives on size, not name. One of my drives is the same size as my external drive. It also happens to be my master boot drive, so I'd rather not harm it. I need a way to differentiate between them before I start the procedure. I also need to know what type of look-up table it needs.
EDIT #2: So I stopped R-Studio and decided to run TestDisk. It can't find any errors, and I'm not sure if I should make a new partition. I am currently running PhotoRec, but it's only turning up junk files. (626 byte .mp3 files, etc.)
Last edited by Guest on 21 Dec 2007 06:40:36 pm; edited 1 time in total |
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NETWizz
Byte by bit
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| Posted: 22 Dec 2007 06:33:49 am Post subject: |
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Look more carefully. PhotoRec and TestDisk are very clear. They list Unix style device names. They also show size, etc. You should take a look at the partition tables on both drives if you still are not sure or the drive vendor name or ID. It really is not hard to choose the right drive.
HINT, the first drive is probably Primary IDE Master or SATA 0 and is likely something like /dev/sda1 or /dev/hda1
THe other one is probably /dev/sda5 or something like /dev/sde1, but take a look and find out. Heck, you could even disconnect the bad drive and see what PhotoRec detects then reconnect it and use the process of elimination to determine the drive.
______________
As far as the Master Boot Record is Concerned, it is very very simple:
It is the first 512 bytes of the disk surface starting at byte 0!
First 446 are the MBR assembly language program!
6 bytes follow that and contain signatures or null values
Next 64 bytes are for the 4 primary partition tables 16 bytes each!
2 bytes for a signature!
512 bytes total!::
Basically, the PC's ROM BIOS has code that copies the contents from the Master Boot Record into RAM and jumps to the program with the processor to run it. No different than with a calculator!
If you know even a little bit of asm, you can take this template or search google for another and change it a little bit and re-assemble. It is actually not too challenging! Then use the "dd" command to put it on the hard drive.
Once you read below, you will have a good understanding how a PC boots
I borrowed (stole this) from http://ata-atapi.com/hiwmbr.htm#T6
Code:
This sector is initially loaded into memory at 0000:7c00 but it immediately relocates itself to 0000:0600.
BEGIN: NOW AT 0000:7C00, RELOCATE
0000:7C00 FA CLI disable int's
0000:7C01 33C0 XOR AX,AX set stack seg to 0000
0000:7C03 8ED0 MOV SS,AX
0000:7C05 BC007C MOV SP,7C00 set stack ptr to 7c00
0000:7C08 8BF4 MOV SI,SP SI now 7c00
0000:7C0A 50 PUSH AX
0000:7C0B 07 POP ES ES now 0000:7c00
0000:7C0C 50 PUSH AX
0000:7C0D 1F POP DS DS now 0000:7c00
0000:7C0E FB STI allow int's
0000:7C0F FC CLD clear direction
0000:7C10 BF0006 MOV DI,0600 DI now 0600
0000:7C13 B90001 MOV CX,0100 move 256 words (512 bytes)
0000:7C16 F2 REPNZ move MBR from 0000:7c00
0000:7C17 A5 MOVSW to 0000:0600
0000:7C18 EA1D060000 JMP 0000:061D jmp to NEW_LOCATION
NEW_LOCATION: NOW AT 0000:0600
0000:061D BEBE07 MOV SI,07BE point to first table entry
0000:0620 B304 MOV BL,04 there are 4 table entries
SEARCH_LOOP1: SEARCH FOR AN ACTIVE ENTRY
0000:0622 803C80 CMP BYTE PTR [SI],80 is this the active entry?
0000:0625 740E JZ FOUND_ACTIVE yes
0000:0627 803C00 CMP BYTE PTR [SI],00 is this an inactive entry?
0000:062A 751C JNZ NOT_ACTIVE no
0000:062C 83C610 ADD SI,+10 incr table ptr by 16
0000:062F FECB DEC BL decr count
0000:0631 75EF JNZ SEARCH_LOOP1 jmp if not end of table
0000:0633 CD18 INT 18 GO TO ROM BASIC
FOUND_ACTIVE: FOUND THE ACTIVE ENTRY
0000:0635 8B14 MOV DX,[SI] set DH/DL for INT 13 call
0000:0637 8B4C02 MOV CX,[SI+02] set CH/CL for INT 13 call
0000:063A 8BEE MOV BP,SI save table ptr
SEARCH_LOOP2: MAKE SURE ONLY ONE ACTIVE ENTRY
0000:063C 83C610 ADD SI,+10 incr table ptr by 16
0000:063F FECB DEC BL decr count
0000:0641 741A JZ READ_BOOT jmp if end of table
0000:0643 803C00 CMP BYTE PTR [SI],00 is this an inactive entry?
0000:0646 74F4 JZ SEARCH_LOOP2 yes
NOT_ACTIVE: MORE THAN ONE ACTIVE ENTRY FOUND
0000:0648 BE8B06 MOV SI,068B display "Invld prttn tbl"
DISPLAY_MSG: DISPLAY MESSAGE LOOP
0000:064B AC LODSB get char of message
0000:064C 3C00 CMP AL,00 end of message
0000:064E 740B JZ HANG yes
0000:0650 56 PUSH SI save SI
0000:0651 BB0700 MOV BX,0007 screen attributes
0000:0654 B40E MOV AH,0E output 1 char of message
0000:0656 CD10 INT 10 to the display
0000:0658 5E POP SI restore SI
0000:0659 EBF0 JMP DISPLAY_MSG do it again
HANG: HANG THE SYSTEM LOOP
0000:065B EBFE JMP HANG sit and stay!
READ_BOOT: READ ACTIVE PARITION BOOT RECORD
0000:065D BF0500 MOV DI,0005 INT 13 retry count
INT13RTRY: INT 13 RETRY LOOP
0000:0660 BB007C MOV BX,7C00
0000:0663 B80102 MOV AX,0201 read 1 sector
0000:0666 57 PUSH DI save DI
0000:0667 CD13 INT 13 read sector into 0000:7c00
0000:0669 5F POP DI restore DI
0000:066A 730C JNB INT13OK jmp if no INT 13
0000:066C 33C0 XOR AX,AX call INT 13 and
0000:066E CD13 INT 13 do disk reset
0000:0670 4F DEC DI decr DI
0000:0671 75ED JNZ INT13RTRY if not zero, try again
0000:0673 BEA306 MOV SI,06A3 display "Errr ldng systm"
0000:0676 EBD3 JMP DISPLAY_MSG jmp to display loop
INT13OK: INT 13 ERROR
0000:0678 BEC206 MOV SI,06C2 "missing op sys"
0000:067B BFFE7D MOV DI,7DFE point to signature
0000:067E 813D55AA CMP WORD PTR [DI],AA55 is signature correct?
0000:0682 75C7 JNZ DISPLAY_MSG no
0000:0684 8BF5 MOV SI,BP set SI
0000:0686 EA007C0000 JMP 0000:7C00 JUMP TO THE BOOT SECTOR
WITH SI POINTING TO
PART TABLE ENTRY
Messages here.
0000:0680 ........ ........ ......49 6e76616c * Inval*
0000:0690 69642070 61727469 74696f6e 20746162 *id partition tab*
0000:06a0 6c650045 72726f72 206c6f61 64696e67 *le.Error loading*
0000:06b0 206f7065 72617469 6e672073 79737465 * operating syste*
0000:06c0 6d004d69 7373696e 67206f70 65726174 *m.Missing operat*
0000:06d0 696e6720 73797374 656d00.. ........ *ing system. *
Data not used.
0000:06d0 ........ ........ ......00 00000000 * .....*
0000:06e0 00000000 00000000 00000000 00000000 *................*
0000:06f0 00000000 00000000 00000000 00000000 *................*
0000:0700 00000000 00000000 00000000 00000000 *................*
0000:0710 00000000 00000000 00000000 00000000 *................*
0000:0720 00000000 00000000 00000000 00000000 *................*
0000:0730 00000000 00000000 00000000 00000000 *................*
0000:0740 00000000 00000000 00000000 00000000 *................*
0000:0750 00000000 00000000 00000000 00000000 *................*
0000:0760 00000000 00000000 00000000 00000000 *................*
0000:0770 00000000 00000000 00000000 00000000 *................*
0000:0780 00000000 00000000 00000000 00000000 *................*
0000:0790 00000000 00000000 00000000 00000000 *................*
0000:07a0 00000000 00000000 00000000 00000000 *................*
0000:07b0 00000000 00000000 00000000 0000.... *............ *
The partition table starts at 0000:07be. Each partition table
entry is 16 bytes. This table defines a single primary partition
which is also an active (bootable) partition.
0000:07b0 ........ ........ ........ ....8001 * ....*
0000:07c0 0100060d fef83e00 00000678 0d000000 *...........x....*
0000:07d0 00000000 00000000 00000000 00000000 *................*
0000:07e0 00000000 00000000 00000000 00000000 *................*
0000:07f0 00000000 00000000 00000000 0000.... *............ *
The last two bytes contain a 55AAH signature.
0000:07f0 ........ ........ ........ ....55aa *..............U.*
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Chasney913
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Joined: 28 Aug 2007
Posts: 117
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| Posted: 22 Dec 2007 06:07:42 pm Post subject: |
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I got around the drive issue by using a different computer, with a different drive. PhotoRec is turning up some correct files, so I know that it is the right drive.
As for "knowing even a little bit of asm", well, I don't. However, I'll look at it and see what I understand. Maybe I should start learning asm.
PhotoRec seems to be turning up a good amount of files, but unfortunately the bulk of what was on the drive was video files, which were re-encoded, and I'm afraid PhotoRec doesn't recognize them. |
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Computer Tech Support => Technology & Calculator Open Topic
