Backup an image file

[Nomadsa]

Hi

For you who want to backup your PC games and don’t mined if it is a 1:1 copy of the original. Using Alcohol 120 write your image file with the appropriate CD protection to a designated folder. Then copy the image file with nero to a CDR (without the folder) now you have a backup copy of your original CD.

The thing that is nice about having the image file on a CD you don’t have to copy it back to your hard drive to use later again. Insert the image file CD into a CD-Rom right click and mount it to the virtual drive of Alcohol, Alcohol will read the image file from the CD-Rom as it did from the hard drive (saving disk space).

Tested with SafeDisk v2 and Securom new v4 no problems found with installation or playing the game from the CD-Rom image file.

Help with testing other games and feedback will be appreciated.

Don’t use this for illegal purposes.

[Duracell]

Hi Nomadsa, Welcome to our forum!

nice and short tutorial;

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Duracell

[celtic_druid]

I would think that a high percentage of images would be too large to fit.

Should be possible I would think to make the whole thing autorun using daemon-script.

[R!Co]

But also note that images are RAW and they can be 700MB<

[Nomadsa]

I encountered this problem with some image files. In Alcohol it shows the disk being written to be 650MB, after the image file has been written the image file size shows 740MB. Using nero to copy the image file to a CD will show ‘ file to large for the disk’ so enabling over burn on nero and write the image file. Outcome the image file size on the new disk shows between 700MB and 707MB. Why I don’t know

Help needed with this one ! Why the additional 90MB on the image file?

[stone_burner]

Why the additional 90MB on the image file?

It's because the image is a raw image and will be ~19% larger than the space it will occupy if burnt to a cdr/w. Of course, if it's burnt as a file, as you are doing, you'll need sufficient space for the total size of the image.

[Nomadsa]

Is there another way that you can copy the image file as a file onto a cdr/w rather than using over burn and keeping the format?
I tried NTFS still too large.
I tested it with a 99min cd on over burn it worked ???. Do I have to worry about the warning nero gives me about using this option if my writer supports it?

[VILLA21]

I encountered this problem with some image files. In Alcohol it shows the disk being written to be 650MB, after the image file has been written the image file size shows 740MB. Using nero to copy the image file to a CD will show ‘ file to large for the disk’ so enabling over burn on nero and write the image file. Outcome the image file size on the new disk shows between 700MB and 707MB. Why I don’t know

Help needed with this one ! Why the additional 90MB on the image file?

It was posted long time ago in CDRFreaks forum and it"s focused on .ISO & .PXI images comparison, but it"s quite useful to understand how the info is stored to an image file:
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"...ISO is the first appearing "file-embedded description" of CD contents.

ISO and PXI (and also other cdrom image files) have some common caracteristics: they contains file names (for plain files and directories), file dates, some others properties (depending on what extension is used (rockridge, joliet, romeo, ...)) and of course file data.
Thus they can be burned or mounted just like regular hard-drives.

A sector on a CD contains 2448 bytes divided into 3 parts:
1) 2048 bytes for plain data.
2) 304 bytes for EDC/ECC (error detection/correction),
which is redundant with 1) (that's the goal for detecting and correcting some errors not catch during some hardware-level stages (known as C1/C2 errors))
3) 96 bytes for subchannels (CD-Text, ...).

ISO stores only the first part (2048 bytes of data),
so ISO isn't suitable for usages where others parts are taken into account or used in a different manner, for instance:
- CD Audio (only audio), Mixed-CD (data+audio), CD-Extra (audio+data) (notice the order), (Super)Video-CD, CD-I, (others ?)
which use the EDC/ECC part for storing audio or data,
- some protections which rely on EDC/ECC part which aren't corresponding to the related plain data part,
- CD-Text or CD-G (quite useless without audio anyway ),
- some other protections which rely on subchannel part,
- ... .

To overcome those limitations, all the copy-CD software (some are although mastering-CD Soft too) have introduced their own format (the vast majority can deal with ISO as well):
PXI for PlexTools, CUE/BIN for CDRWin, CDJ for Discjuggler, CCD/BIN/SUB for CloneCD, BWx for BlindSuite, MDS/BIN/SUB for
Alcohol, NRG for Nero, ...

Of course as this isn't complex enough, you might encounter some other extensions (RAW = BIN, ...) or some variants (ISO storing EDC/ECC thus acting like BIN/RAW files, ...).

In addition, some file formats are able to store all the sessions, some only the first, some take hybrid CD (MAC and PC data).
I don't know for sure how qualify ISO and PXI for that.

To re-focus on your question, PXI is able to store data, EDC/ECC and CD-Text, CD-G i.e. some subchannels but I'm not sure if all subchannels are taken into account (there are 8 subchannels named from P to W)).
You can easily notice it. A simple way to do this is making an image out of a CD and doing some maths.

75 sectors are read/burned per second at x1.
75 sectors * 2048 bytes (for data) = 150 ko (1 ko = 1024 bytes !)
75 sectors * 2352 bytes (for audio) = 176400 bytes
(176400 = 44100 Hz * 2 (16 bits) * 2 (stereo))
(2352 = 2048 (plain data) + 304 (EDC/ECC))
Those numbers may ring some bells

So imagine you make an image of a 74 min 00s CD.
For an ISO, the resulting image size should be near 74*60*75*2048 = 681984000 bytes ~ 650 Mb (1 048 576 bytes)
For a BIN (data + EDC/ECC), size near 74*60*75*2352 = 783216000 bytes.
For a PXI (data + EDC/ECC + 96 bytes of subchannel), 74*60*75*2448 = 815184000 bytes.
Some softwares only take the first subchannels (16 bytes instead of the full 96 bytes), PXI may be in this case.
In addition, some file formats store additional information into the image, so there is small "size-overheat".
The bigger the CD is, the more accurate the calculations are.

Reversing the process may interest you as well.
So you have a data CD with (hum) some files totalizing 521 548 654 bytes (manual random ), this leads to those results:
521548654/75/2048 (remember: data) ~ 3337 s = 55 min 37 s
ISO size near 512548654 bytes (the actual sum of all file sizes) (plus somewhat 1 Mb, somewhat 10 Mb).
BIN/RAW size near 512548654/2048*2352 ~ 588 630 095 bytes (quite bigger).
PXI (I assume 96 bytes subchannel) size near 512548654/2048*2448 ~ 612 655 813 bytes (even bigger).
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Hope that helps

[stone_burner]

I tested it with a 99min cd on over burn it worked ???. Do I have to worry about the warning nero gives me about using this option if my writer supports it?

No. Nero will give you that warning any time you need to use a 90min or 99min cd. Don't worry about it.