Help file

Help on how to use HxD.
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Terpsichore
Posts: 3
Joined: 06 Feb 2015 18:05

Help file

Post by Terpsichore » 06 Feb 2015 20:13

Is there one? I've just started using HxD, but all I can find to tell me what to do is a one-page FAQ.

Maël
Site Admin
Posts: 1137
Joined: 12 Mar 2005 14:15

Re: Help file

Post by Maël » 07 Feb 2015 10:30

There is no help file. If you have any question you can post it here.

Terpsichore
Posts: 3
Joined: 06 Feb 2015 18:05

Re: Help file

Post by Terpsichore » 07 Feb 2015 15:13

I'm looking for a text file that I believe to be on one of four HDs that I own, but which got accidentally deleted. I can't remember which disk it was. I tried out different trial versions of apps that claim to be able to recover lost data, but I'm reluctant to buy something unless I'm sure it will work. HxD is my last resort.

First I noticed it didn't seem to recognize my other HD. I'm using Windows 7, and my device manager shows a 2nd hard drive connected (it's the one I wanted to scan, actually). All HxD offered me was Optical Drive 1, which is the currently active one. But I tried it out anyway. I tried searching for a string that I knew was in a text file in My Documents. After 1 1/2 hours, it popped up a message saying "not found". Obviously I'm doing something wrong.

I'd like something that at least tells me what I'm looking at when I view the screen. There is a list of 9-digit addresses on the left. If my arithmetic is right, that adds up to 64Gb, not enough to span the range of a HD these days. So I guess 000000000 must mean an address within a block of some sort, and there must be many blocks (sorry, I know almost nothing about the structure of HDs). Can you at least tell me what those numbers represent?

Maël
Site Admin
Posts: 1137
Joined: 12 Mar 2005 14:15

Re: Help file

Post by Maël » 07 Feb 2015 15:35

Terpsichore wrote:I'm looking for a text file that I believe to be on one of four HDs that I own, but which got accidentally deleted. I can't remember which disk it was. I tried out different trial versions of apps that claim to be able to recover lost data, but I'm reluctant to buy something unless I'm sure it will work. HxD is my last resort.
There seem to be quite some programs that can undelete files and that are free. TestDisk is an opensource one. I bet there are others you can find. I would suggest however to not install anything on the disk which holds the data you want to recover. Writing data to this disk (or installing programs on it) may finally delete the file you want to recover. A good option is a recovery disk or live CD (I think TestDisk has this too, check out their website).
All HxD offered me was Optical Drive 1, which is the currently active one.
You have to run HxD as administrator to see all drives/disks. Note however that HxD is not really suited for recovering data, it would require a lot of manual work and knowledge.
But I tried it out anyway. I tried searching for a string that I knew was in a text file in My Documents. After 1 1/2 hours, it popped up a message saying "not found". Obviously I'm doing something wrong.
Yes, the optical drive is not the disk you want. Be aware though that text files may not be contiguous on the drive (file systems can split files in several blocks and spread them all around the disk), or they may be compressed or use a special encoding (such at UTF-8). It may be that you wont find the string even if it exists.
I'd like something that at least tells me what I'm looking at when I view the screen. There is a list of 9-digit addresses on the left.
http://en.wikipedia.org/wiki/Hex_editor gives an introduction, but the German one explains the layout of hex editors better.
You have three columns, left is address/offset (so a position in the file). By default offsets are in hexadecimal numbers, clicking on "offset" switches between decimal, hexadecimal, and octal. Middle is the data shown as a sequence of hexadecimal numbers (this is always hexadecimal, you cannot change to decimal or another display). The right column shows a possible interpretation as text of the same data shown in the middle. It may well be that this looks like random characters, especially if the data is not really text (but an image or some other binary data, or if the encoding is not the currently selected one, see the menu View|Charset).
If my arithmetic is right, that adds up to 64Gb, not enough to span the range of a HD these days.
If you go to the end of the document the Offset (=position) will be the file size. Optical disk is probably a DVD or Bluray drive, so it's not what you want.
So I guess 000000000 must mean an address within a block of some sort, and there must be many blocks (sorry, I know almost nothing about the structure of HDs). Can you at least tell me what those numbers represent?
Those numbers are very simply byte addresses or offsets. That means positions starting from the start of the file or disk (depending what you opened, a file or a disk). So in case of a drive, if you go at the end of the drive, the offset in the statusbar (bottom left) will tell you the drive's size in bytes. No block or sectors involved. Sectors are separated by horizontal lines, but this is just shown for convenience, because it can be useful when editing file systems for example.

Ideally there would be special support for file systems, but currently there is not, so what you see is really the raw contents of the disk, byte by byte.

Terpsichore
Posts: 3
Joined: 06 Feb 2015 18:05

Re: Help file

Post by Terpsichore » 07 Feb 2015 18:59

Okay, thanks for now. I might be back when I've digested all that and thought about it some more.

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