VOGONS


Which software to preserve CDs?

Topic actions

Reply 20 of 28, by darry

User metadata
Rank l33t
Rank
l33t
BardBun wrote on 2021-02-16, 11:26:
1541 wrote on 2021-02-16, 11:24:

You can't even use .iso if your game-CD contains audio tracks, like WarCraft II, Dungeon Keeper, Fury³ and many more...

Really?
I have a different game called Q-POP, the CD contains Audio that you can also play back in a real CD Player, works just fine as .iso as well.

My guess is that the .ISO file that you have is an "ISO" image in name only and is actually in another format. CD audio tracks are outside the scope of an ISO 9660 image file (which is what a file with an ISO extension is supposed to be, at least in theory ) .

My understanding is as follows, sorry if this either common knowledge to many people or if there are any errors/misconceptions (fell free to correct me) :

a) An audio CD (Red Book) contains digital audio tracks meant to be played by an audio CD player .
b) A CD-ROM (Yellow Book) is a disc where a filesystem is present in a track tagged as "DATA" rather than audio . This track will contain a filesystem which will typically be of the ISO 9660 type .
c) A CD-ROM that contains both a and b is usually referred to as a mixed-mode disc .
d) "a" cannot be dumped into a true to form ISO file image because it has no data track containing an ISO 9660 filesystem
e) By definition of what it is, a true to form ISO file image can be made of the ISO 9660 filesystem contained in the data track on "b" or "c", but in the case of "c", the image file will not contain any CD audio tracks as these have nothing to do with the ISO 9660 filesystem contained only on the data track .
f) There are ways to dump a complete (all tracks, both data and audio) disc image of "a", "b" or "c" (and also of other disc formats), but not into ISO files . cue/bin and Nero's NRG format are but two examples.
g) AFAIK, the degree of accuracy with which "f" is possible will depend on the software used, the optical drive used and possibly even the limitations of the dump format chosen .
h) I seem to recall there being some software that would dump "b" or "c" into into what it called and "ISO" file, but was actually some other, possibly oddball, format .

See
https://en.wikipedia.org/wiki/Mixed_Mode_CD EDIT : this one is not very well written at this point in time , IMHO .
https://en.wikipedia.org/wiki/ISO_9660
https://en.wikipedia.org/wiki/CD-ROM
https://en.wikipedia.org/wiki/Compact_Disc_Digital_Audio
https://en.wikipedia.org/wiki/Rainbow_Books

Reply 21 of 28, by Benedikt

User metadata
Rank Member
Rank
Member
darry wrote on 2021-02-16, 15:40:
My guess is that the .ISO file that you have is an "ISO" image in name only and is actually in another format. CD audio tracks a […]
Show full quote

My guess is that the .ISO file that you have is an "ISO" image in name only and is actually in another format. CD audio tracks are outside the scope of an ISO 9660 image file (which is what a file with an ISO extension is supposed to be, at least in theory ) .

My understanding is as follows, sorry if this either common knowledge to many people or if there are any errors/misconceptions (fell free to correct me) :

a) An audio CD (Red Book) contains digital audio tracks meant to be played by an audio CD player .
b) A CD-ROM (Yellow Book) is a disc where a filesystem is present in a track tagged as "DATA" rather than audio . This track will contain a filesystem which will typically be of the ISO 9660 type .
c) A CD-ROM that contains both a and b is usually referred to as a mixed-mode disc .
d) "a" cannot be dumped into a true to form ISO file image because it has no data track containing an ISO 9660 filesystem
e) By definition of what it is, a true to form ISO file image can be made of the ISO 9660 filesystem contained in the data track on "b" or "c", but in the case of "c", the image file will not contain any CD audio tracks as these have nothing to do with the ISO 9660 filesystem contained only on the data track .
f) There are ways to dump a complete (all tracks, both data and audio) disc image of "a", "b" or "c" (and also of other disc formats), but not into ISO files . cue/bin and Nero's NRG format are but two examples.
g) AFAIK, the degree of accuracy with which "f" is possible will depend on the software used, the optical drive used and possibly even the limitations of the dump format chosen .
h) I seem to recall there being some software that would dump "b" or "c" into into what it called and "ISO" file, but was actually some other, possibly oddball, format .

An "iso" file with CD audio is most likely a renamed bin file from a bin/cue pair.
For disks without audio tracks imaged without sub-channel data the two formats should be identical.
I'm just wondering how e.g. a virtual CD drive would know where the audio starts if there's no cue file.

Reply 22 of 28, by darry

User metadata
Rank l33t
Rank
l33t
Benedikt wrote on 2021-02-16, 17:44:
An "iso" file with CD audio is most likely a renamed bin file from a bin/cue pair. For disks without audio tracks imaged without […]
Show full quote
darry wrote on 2021-02-16, 15:40:
My guess is that the .ISO file that you have is an "ISO" image in name only and is actually in another format. CD audio tracks a […]
Show full quote

My guess is that the .ISO file that you have is an "ISO" image in name only and is actually in another format. CD audio tracks are outside the scope of an ISO 9660 image file (which is what a file with an ISO extension is supposed to be, at least in theory ) .

My understanding is as follows, sorry if this either common knowledge to many people or if there are any errors/misconceptions (fell free to correct me) :

a) An audio CD (Red Book) contains digital audio tracks meant to be played by an audio CD player .
b) A CD-ROM (Yellow Book) is a disc where a filesystem is present in a track tagged as "DATA" rather than audio . This track will contain a filesystem which will typically be of the ISO 9660 type .
c) A CD-ROM that contains both a and b is usually referred to as a mixed-mode disc .
d) "a" cannot be dumped into a true to form ISO file image because it has no data track containing an ISO 9660 filesystem
e) By definition of what it is, a true to form ISO file image can be made of the ISO 9660 filesystem contained in the data track on "b" or "c", but in the case of "c", the image file will not contain any CD audio tracks as these have nothing to do with the ISO 9660 filesystem contained only on the data track .
f) There are ways to dump a complete (all tracks, both data and audio) disc image of "a", "b" or "c" (and also of other disc formats), but not into ISO files . cue/bin and Nero's NRG format are but two examples.
g) AFAIK, the degree of accuracy with which "f" is possible will depend on the software used, the optical drive used and possibly even the limitations of the dump format chosen .
h) I seem to recall there being some software that would dump "b" or "c" into into what it called and "ISO" file, but was actually some other, possibly oddball, format .

An "iso" file with CD audio is most likely a renamed bin file from a bin/cue pair.
For disks without audio tracks imaged without sub-channel data the two formats should be identical.
I'm just wondering how e.g. a virtual CD drive would know where the audio starts if there's no cue file.

It could simply be a renamed NRG or other single-file image format that happens to be supported in whatever application is being used and the said application is probably smart enough to not just assume it is an ISO file based on the extension and actually runs some sanity checks on the image content before trying to parse or mount it .

Reply 23 of 28, by BardBun

User metadata
Rank Newbie
Rank
Newbie

@darry @Benedikt the programme I use is called ImgBurn https://www.imgburn.com/
It's basically 1 click to create an .iso file from any CD.

Interesting to know that .iso doesn't support audio tracks by default, but whatever that programme does when it creates the .iso makes it work, so it's still a good alternative?
Afterall its created .iso container thingy still works easy with Windows 10 mounting and of course also in DOSBox, without the hassle of trying to make .bin/.cue or the other horrendous formats work. (and the games have no issue playing back the music)

Audio Tracks can be played on any media player from the mounted .iso as well as when its burned onto a CD again, it'll still be played on a CD player.

Reply 24 of 28, by 1541

User metadata
Rank Member
Rank
Member

Imgburn is a good example.
If you provide a CD with audio tracks, imgburn will automatically detect it and switch from the extension. ISO to .BIN for saving the image.
If you want to force it back to .ISO you will receive a popup message that this mode is not supported on this kind of CDs

Windows 98 SE inofficial Service Pack & NUSB (German)
Windows 9x device drivers and tools (German)

Reply 25 of 28, by Zup

User metadata
Rank Oldbie
Rank
Oldbie
BardBun wrote:

ImgBurn to turn them into .iso files and everything is fine.

No need to use other stupid formats that you need like 4 different programmes to convert over and over to get a format that you can easily use on Windows / DOSBox / etc.

In some alternate reality, all CD-ROMs are made strictly following those ISO9660 standards. People could use their right to make private copies, and there would be no need to use anything except ISO and CUE/BIN (remember: ISO files can no stores mixed-mode CDs).

In this reality, software manufacturers abused standards so their CDs could no t be copied. My test CD expects to NOT find some sectors, or expect to read some sectors with CRC errors; if it doesn't find those "marks", it won't work. An ISO image would return those sectors as "valid" so it won't pass the check. And not every game on earth had a patch (nor a patched image is a properly preserved one).

mr.cat wrote:

Did you take a closer look at the differences in MDF? It could be just different type of filler bytes being used by each software (for the sectors that couldn't be read).

It's hard to see:
- It starts with some bytes that appear valid (but are different).
- Then it seems that Alcohol reads data but CDBurnerXP keep "filler" bytes (Alcohol read diferent bytes but CDBurnerXP stores 0xCC).
- Then, both programs seems to store "filler" bytes, but they are different (0xCC in CDBurnerXP vs 0x55 in Alcohol).
Both images were made using the same computer, with the same drive.

mr.cat wrote:

For the MDS, it's a measurement of sorts, but what exactly is measured isn't clear to me (timing?). It's different for each drive, that much I know. But maybe there's even a difference between runs on the same drive and same software?

I don't think it is a measurement, but a layout description (much like CUE/BIN). In a CUE/BIN, the BIN file gets the data stored, while the CUE contains the layout (number of tracks, type of tracks, tracks position). In this case, I think that MDS contains the disc layout plus information about "wrong" sectors (i.e.: sector xxx exists, but was readed with CRC errors, or sector yyy does not exists). So I guess that CDBurnerXP stored a "basic" layout of the disc without preserving those errors, while Alcohol stored everything it could find about every sector.

I have traveled across the universe and through the years to find Her.
Sometimes going all the way is just a start...

I'm selling some stuff!

Reply 26 of 28, by konc

User metadata
Rank Oldbie
Rank
Oldbie
BardBun wrote on 2021-02-16, 11:26:
1541 wrote on 2021-02-16, 11:24:

You can't even use .iso if your game-CD contains audio tracks, like WarCraft II, Dungeon Keeper, Fury³ and many more...

Really?
I have a different game called Q-POP, the CD contains Audio that you can also play back in a real CD Player, works just fine as .iso as well.

Well, really.
ISO can't have cd audio, there is no way you can have cd audio with an ISO image
BIN/CUE is fine for data+audio
Until this point I agree that the best approach is going for the simplest image type possible.
But when copy protection comes into play it's another thing, none of the above can hold the information for a working image.

Reply 27 of 28, by mr.cat

User metadata
Rank Member
Rank
Member

Thanks Zup, so there is some significance on the used software with MDF/MDS.
About that MDS parsing: CDemu can use these MDF/MDS images and it does so via libmirage. This is all open source stuff AFAICR, so that's one place to look for some parsing code.

Reply 28 of 28, by BardBun

User metadata
Rank Newbie
Rank
Newbie
konc wrote on 2021-02-17, 09:28:
Well, really. ISO can't have cd audio, there is no way you can have cd audio with an ISO image BIN/CUE is fine for data+audio Un […]
Show full quote
BardBun wrote on 2021-02-16, 11:26:
1541 wrote on 2021-02-16, 11:24:

You can't even use .iso if your game-CD contains audio tracks, like WarCraft II, Dungeon Keeper, Fury³ and many more...

Really?
I have a different game called Q-POP, the CD contains Audio that you can also play back in a real CD Player, works just fine as .iso as well.

Well, really.
ISO can't have cd audio, there is no way you can have cd audio with an ISO image
BIN/CUE is fine for data+audio
Until this point I agree that the best approach is going for the simplest image type possible.
But when copy protection comes into play it's another thing, none of the above can hold the information for a working image.

We, I'm glad that today I've learned quite a lot of new important things, thanks for the info! (you and everyone else who replied to me)

And you are absolutely right, the game CD was turned into a bin/cue, I must have had some weird blindness there to not notice that.