Curious HDD problem

[Davy]

I run win 7 pro x64, I NTFS formatted a SATA HDD, ran Check disk that came up 'OK' BUT when using Acronis to clone the main drive it gets stuck on analyzing partition.... 'Failed to read sector 174,781,159'.


I can accept the drive is 'probably goosed' but why should running Check disk give me the 'all clear'? It does show up as my third drive and running Diskpart reveals nothing hidden or suchlike, I'm just curious more than anything, what am I missing here?


Dave

 

[samuria]

The answer is simple when disk check is run and reports error it marks sector as bad so when you run it again it doesn't check the bad blocks so it doesn't report a fault

If you clone a disk with bad sector they will be written to the new drive and can't be reversed and you don't know what's corrupted. You must do a clean install

 

[Davy]

Hi, thank's samuria.


It 'was' a HDD that was corrupted so I did a fresh install of windows onto a SSD. I can see the point you are making.... if I format the said drive are we saying it will retain the bad sector markings? I can understand cloning a 'iffy' drive will produce the same results or even worse.


In fact samura you are probably right - I had a duff BT cordless phone charger that created havoc when it generated a fault, it crashed the conmputer from time to time, the devil took some time to locate, as you say I DID clone the drive in between time....! The computer ran OK'ish after discovering and removing this 'wall wart charger' but some files were corrupted in the process.


Soooo this time I made 2 back ups, 1 in extreme emergency which is under lock and key and the 2nd to keep up to date with which I do every month or two.



Just that I can't understand formatting the HDD and running Check Disk which came up fine I should get an Acronis 'reading sector error'.



Dave

 

[Alejandro85]

A possibility is that you didn't specify a full check and repair (aka "surface analysis) when you ran chkdsk.

When you ran it with /f /r parameters it scans every single disk sector for read/write inconsistence and marks as damaged those that came up with errors, but when you don't put those parameters it just check the filesystem structure for logical errors only, while the actual data portion is left untouched. Many errors can still be there when running in this basic mode.
There is a great difference in the time it takes to complete in each mode. While the basic mode runs in a couple of minutes, the full analysis can easily take hours.

An imaging program, by its very nature, must read every single sector, so it'll naturally bump into bad sectors if there are any and you ran chkdsk in normal mode.

Another explanation is that Acronis just ignored the "bad sectors" marks and just read the bad sector again, triggering the problem. Since clones generally don't try to interpret the filesystem but copy every single byte, there is a chance of it doing this.

Yet another, more unlikely, posibility is that the disk going bad between the executions of chkdsk and Acronis .

 

[Davy]

-Sorted-

@Alejandro85


Yes Sir... I tried all that and wouldn't have non - I've cracked it thanks.


I remember once I accidentally long formatted my Storage drive..... in the day's I didn't clone but I got em' all back thanks to 'Get my Data', mind you it'd let me see the recovered files BUT I had to pay for the licence to retreive them..... so this got me thinking at the time. I cloned a drive and had to format it three or four times before nothing could be retrieved. Let this be a warning to folks who wanna' wipe their drives so they can pass on their computers say. If you think about it all we are doing is leaving magnetic impressions, I thought about walking in snow - the footprint is bigger than the shoe, I Don't know if this is true or not? Mind you I used Windows format, explains how using these dedicated programs take forever.

My policy now is to smash em' up, the platter as well after scratching them to death!

In Disk management the drive was all greyed out - 'NO data' Diskpart reported, I don't know what I did to get the machine to see the hard drive - I tried that many times. So then I decided to try and Clone the main drive and kept getting 'Failed to read sector174,781,159' the whole thing just hung on me - same when I tried to 'Add a disk' with Acronis.... I was about to 'clod' the SATA drive.

I'm more curious as to know what was going on here rather than get the drive working, the drive shows full capacity, gives no errors and boots as expected after cloning.... I'm stumped. It was late when I came across some website saying this happens when the partition or clusters get the same serial number as the main drive or something like that.

Dave

 

[Megahertz07]

If you do a quick format the data isn't erased from clusters and can be retrieved. If you do a format (can take days), all clusters will erased and data can't be retrieved by normal software.

 

[Alejandro85]

If you do a quick format the data isn't erased from clusters and can be retrieved. If you do a format (can take days), all clusters will erased and data can't be retrieved by normal software.

No, it doesn't. A normal format neither erases anything, the added time is just spent doing a "surface analysis", the same that a full chkdsk does, and marks bad sectors along the way. The only thing really erased is the filesystem tables, which marks everything as "free" and leaves the data alone, which makes data restoration possible.

To actually delete everything you need dedicated data wipe software. Or full-disk encryption and throw away the key. Or physically destroy the disk.

 

[Davy]

Megahertz07


Yes I am aware of differring formatting, I did a full format using windows, for anything serious I always give it two or three passes now.


Dave

 

[Megahertz07]

No, it doesn't. A normal format neither erases anything, the added time is just spent doing a "surface analysis", the same that a full chkdsk does, and marks bad sectors along the way. The only thing really erased is the filesystem tables, which marks everything as "free" and leaves the data alone, which makes data restoration possible.

To actually delete everything you need dedicated data wipe software. Or full-disk encryption and throw away the key. Or physically destroy the disk.

You're right.

I was quite sure I read that nowadays a full format would erase the data as a diskpart clean all command does.

 

[TechnoMage2016]

Two things not mentioned, are:
A DOS Format, which scours every sector on the HD, thus erasing anything previously stored there.
Yes it's slow, but very thorough, and unreliable sectors are entered into the Bad Sector Map, and so will never be used.

And something very seldom used even by most tech's, is a "Low Level Format".
Again, every sector is scoured and examined for it's ability to reliably retain data, and any sector that does not pass the test is added to the bad sector map, which is a permanent part of the HD.

I've used that technique often, when I've received a HD from questionable sources.

Just like the DOS format, it takes a while, but puts the drive back to "Factory Fresh" condition.

Cheers Mates!
TM