22 April, 2008

Procedure used to recover data from a quick-erased CD-RW disc

1. Make a file of exactly the size of the cdrw disc's capacity (650MB in my case).
(this step may not be needed)

2. With Nero I created a new project and added the file to it so that I have the disc filled. I gues you can also fill up the disc with other files.
The reason why I fill the disc is because I want Nero to make a session that uses the entire disc. Like I wrote earlier in this thread I experienced that my CD-Drive refuses to read off the disc beyond the session's boundaries. When you quick-erase a disc there is no session anymore so the drive will not read at all. Burning a new session will overwrite the data and burning only a small session will NOT make the drive read the other data that is still on the disc.
The reason why I used the one big file is so that I could later on recognize which part of the disc was overwritten by this file because this file contained all zeros (0x00).

3. I pressed burn and selected disc-at-once. Then while Nero was burning the leadin I pressed cancel. My CD-Drive finished writing the lead-in and Nero reported an error.
This is what was accomplished however: Now the disc contains a session that says that the used disc size is the complete disc. Nero did not get to writing file because I cancelled it. Good thing because I don't want Nero to write any files because my old data will get overwritten!
I gues it works the same with different writing software. Another method that I used during a test was simply press the reset button of the computer when the burning software was done with writing the lead-in and started with the files.

4. I had to restart the computer after cancelling burning.
With the cdrw disc inserted I saw in "my computer" that windows recognized that the disc was 650MB, clicking on it gave an error. Good so far!

Now with IsoBuster you can extract the sectors from a disc to a file. This is what I did.
I gues that if you have data-recovery software at this point it will be usefull because now (if all went well;)) the CD-Drive WILL read data from the entire disc. Anyway, I used ISO-Buster because the files that I needed to recover where a bit odd for nowadays (.XM, .S3M, .MP3):
In IsoBuster I had to do several steps:

Step 1: Find out from and to which sector the drive will read
By choosing "Sector View" you can look at any given sector.
Here I found out what the first and the last sectors where that are readable. (Hint I used the method for the old game: "Gues a number below 100, I'll tell if it is higher or lower than what you gues")
Step 2: Extract the actual sectors
By choosing "Extract From-To" you can extract any given range of sectors to a file. My disc was a data-disc so I choose the first extraction type "User data, 2048 bytes/block...".

In the end I got a .tao file which was about 650MB. I ran several programs on it to look for files inside a file by searching for file-header-paterns:
1. Multi Ripper 2.80 (for DOS, for the .XM files. It does many other file formats as well (jpg,png, bmp,wav,etc,etc +100). Try google with this query: Multi Ripper 2.80. I still had the file from good old days but I saw several good search results)

2. Winamp for mp3.
Winamp will scan any file when you give it the extension .mp3 and play it as one big song (so I renamed the .tao file to .mp3). I used the discwriter to get a .wav and the Adobe Audition to manually cut and save my songs. I looked at the MP3 file format and it is hard to find an mp3 file in a big file because it has no clear header just a bunch of mpeg-frames in most cases for me . A lot of my files had no ID3v2 or ID3v1 tags... But after a couple of hours I recovered everything.

Finally a list of used stuff:

Software:
- IsoBuster v1.5
- Nero 6.3.0.3
- Multi Ripper 2.80
- WinAmp v5.02
- Windows XP Pro NL (patched up)

Hardware:
- NEC DVDRW ND1300A 1.06

Disc:
- some old 4 speed cdrw

Convert Stubborn Webpage To .pdf

I have come across some websites that i wanted to save the page for later review. I found that i was having some problems with certain sites. I found a way around it.

what you need:adobe acrobat 6 pro or better
popupcop

there may be a simpler way to do this but i found that this works:

when at a webpage that you want to copy (YOU MUST BE USING IE AND HAVE BOTH POPUPCOP INSTALLED AND ADOBE ACROBAT 6 PRO OR HIGHER, ACROBAT ICON MUST BE IN IE TOOLBAR TO CONVERT TO .PDF), slide popupcops popup intensity bar to the far left, now click on adobe acrobat icon to convert webpage to .pdf document. I have yet to find a webpage where this trick does not work.