April 24th, 2015, 16:46
Leo wrote:It is not "encoded", the drive just returns some "garbage" from its buffer without actual reading from disk sectors.
This is the data normally sent or returned by a read or write command. This data may be encoded.
April 25th, 2015, 4:25
Leo wrote:It is not "encoded", the drive just returns some "garbage" from its buffer without actual reading from disk sectors. As it was already said, most of modern drives do not support read long command, they just have a "plug" for compatibility with older software/hardware.
I used read long for data carving in the age of early ATA drives (less than 10GB), it worked and allowed to get some raw data that sometimes was of some use (for example to reconstruct FAT or DIR fragments etc.). But it was more than 15 years ago, and never worked with newer drives.
April 26th, 2015, 7:13
April 27th, 2015, 22:54
Spildit wrote:butchie3980 wrote:Yeah I guess we've come full circle, eh? I'm trying to recover data. Previous scans have shown the drive was having corruption everywhere, which I don't believe. I don't have experience in determining the cause, so I'm afraid of making things worse if I try regenerating defect lists or modules. I figure the safest thing to try with my limited knowledge is to do long reads of the whold disk and try to carve out files from the image.
What is the full model of the drive ?
Can you scan any sector at all ?
Maybe the translator is not initializing properly due to damaged head or other causes.
Does the drive produces strange sounds and clicking noises ?
Were you able to get access to the firmware modules using something like SeDiv DEMO or WDR or WDMarvel ?
The drive might as well have typical issues like the slow problem and cloning the drive in such state might not be a wise decision.
Again, if data is important you should stop messing with the drive, and i don't think the read long commands would be of help on your problem anyhow !
April 28th, 2015, 1:17
April 28th, 2015, 19:08
Tomset wrote:All it a waste of time.
Required accuracy of the information being read.
Long read does not guarantee the reliability.
Can help only in very rare cases.
When the information can be verified by other methods, for example by sense.
April 29th, 2015, 4:18
April 29th, 2015, 17:11
Tomset wrote:maximus,
Oh!
there is not any coding.
there is an algorithm for the Hamming code.
I advise you to read this article:
https://en.wikipedia.org/wiki/Hamming_code
And to imagine that a few bits can not be deducted.
April 30th, 2015, 3:22
I would not mind if anyone could provide more specific details on how different drives implement the hamming code algorithm.
April 30th, 2015, 19:25
April 30th, 2015, 20:07
long sector:
0: fb e7 6f 99 ab 76 72 01 95 d8 a3 c1 c2 e8 21 57 ..o..vr.......!W
10: aa 41 2a 9f 78 f2 8d 96 9c 76 33 ed 05 5f 9d 60 .A*.x....v3.._.`
20: ce 0b 11 b3 2c 81 d7 9c 77 de 0a 75 5f b2 af 49 ....,...w..u_..I
30: b9 67 8b fb 9e f4 16 93 26 d2 69 ea a5 e6 0a 47 .g......&.i....G
40: 51 a2 fa 82 06 d3 70 d2 b5 cb 90 ab 08 a9 5a ee Q.....p.......Z.
50: a4 e2 be d8 92 a3 46 be 19 19 aa 33 e9 b4 1c 83 ......F....3....
60: 9a 4a 39 9d 70 bc 9a d5 6b 78 e2 ba 69 d1 bd bc .J9.p...kx..i...
70: 3a 2b 95 69 a3 f2 b6 eb 8c a6 fa 25 13 7f af e9 :+.i.......%....
80: 47 99 9a ba d6 2b 2c a2 3c 12 67 6c b3 ea 11 b6 G....+,.<.gl....
90: 23 b4 e6 ae 08 ec ad 41 4e eb 65 82 58 6e c7 e1 #......AN.e.Xn..
a0: b2 38 02 b7 12 bd ed e1 44 5f 9c 8d 29 7b 11 9c .8......D_..){..
b0: e3 06 65 ea 4f 09 15 56 d5 56 57 91 a5 d2 9c b2 ..e.O..V.VW.....
c0: dd 0a 20 ba 27 ce 9b 2f 46 12 6d e5 2b ac 14 21 .. .'../F.m.+..!
d0: 1b 6c 76 ca 89 15 d1 78 9c a2 88 67 a5 d9 fe 36 .lv....x...g...6
e0: 60 84 3e 4a f8 16 79 c9 cd 78 6e 51 4b 19 e4 50 `.>J..y..xnQK..P
f0: 4e 9a ea c7 63 61 fd d2 0a 51 49 f8 7a 67 57 ab N...ca...QI.zgW.
100: b0 21 da e7 7f bf de b8 d4 51 35 01 05 e6 56 ff .!.......Q5...V.
110: 2e da 96 8c 60 6a 44 ac bc 97 4d 3a 2a 85 54 d1 ....`jD...M:*.T.
120: 79 2e ab 9f e2 54 9b 92 f4 c1 68 db ac ed 45 0b y....T....h...E.
130: e2 93 36 e5 96 a7 6e 69 dd 69 9b 56 39 be bb 29 ..6...ni.i.V9..)
140: 4f 58 ce 39 1f a3 79 4a 68 28 8c f7 21 4a d9 8a OX.9..yJh(..!J..
150: 81 32 8a 63 8a ff 2a 6b d5 92 9a ee 76 20 7f 07 .2.c..*k....v ..
160: 56 38 dd 8a 68 61 65 a0 a4 8c 91 c6 69 70 ac ad V8..hae.....ip..
170: 2a 26 b3 6d 6d 47 1b 49 7f 06 96 6f 56 29 89 44 *&.mmG.I...oV).D
180: 64 84 d7 19 17 d5 57 ba 76 d5 d2 b3 7d 5a b8 56 d.....W.v...}Z.V
190: 82 f0 d1 b8 a5 a2 ea b5 f9 9e bb 5d 62 e5 5a 5f ...........]b.Z_
1a0: cb 95 e7 14 9b 68 c5 2a 1d ab 37 5d 2b df 82 26 .....h.*..7]+..&
1b0: 76 26 57 aa 5d c6 aa e7 50 70 59 0a a2 69 e2 1e v&W.]...PpY..i..
1c0: 26 6c b2 07 f6 c6 23 9b 29 29 ba 9a 95 96 51 c8 &l....#.))....Q.
1d0: ef 66 a0 b6 db 54 a5 71 41 49 24 94 ec fd b6 9a .f...T.qAI$.....
1e0: 7f 79 4e d9 6b 92 0d a5 78 55 49 11 29 88 94 85 .yN.k...xUI.)...
1f0: c3 9a 77 5b 9d 89 9d e4 d2 9d 5f 3a 7a 20 95 e8 ..w[......_:z ..
ecc data:
200: 49 29 59 69 e5 24 fb 7f cd e3 b5 94 5e 93 d6 09 I)Yi.$......^...
210: 2f c9 70 9f 01 e3 0b 75 18 b3 e8 38 01 9e 3b 7a /.p....u...8..;z
220: 50 28 21 cc 05 68 40 25 b2 33 c9 a7 1e 1f 14 cc P(!..h@%.3......
230: 4d 40 30 6e ef 94 03 ff
normal read:
0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
20: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
30: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
40: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
1f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
April 30th, 2015, 20:24
Read any information sufficient to restore or not.
And if it is not enough, nor a miracle, do not allow you to restore reliable information.
All hope.
Repeat reading many times as unstable-read place does not give so much information that it will be possible to restore the algorithm.
May 1st, 2015, 11:01
maximus wrote:Read any information sufficient to restore or not.
And if it is not enough, nor a miracle, do not allow you to restore reliable information.
All hope.
Repeat reading many times as unstable-read place does not give so much information that it will be possible to restore the algorithm.
The hamming code is supposed to be able to correct for small errors. If you are saying that when the errors go over that limit that the data becomes virtually unrecoverable due to the complexity of the algorithm, I would understand. But I wish to see it for myself. I want to know how it works.
May 1st, 2015, 11:29
May 2nd, 2015, 20:57
May 3rd, 2015, 10:35
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