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Backing up DOS era CD-ROM games?

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Reply 20 of 41, by firage

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Audio tracks don't figure into the copy protection part; I meant to say they present the only challenge in backing up DOS era discs instead of any DRM methods. DOS games look for a file on the disc or check the label and that's it, well in the domain of the basic ISO format. For CD audio support, you need an alternative image format. With real protections later on, ISO is out also for its lack of raw/subchannel data support.

It's good to check for matching CRC from multiple reads, because there's very little error detection in the audio ripping process otherwise. When audio glitches happen, only the most severe sync errors pop up a notification. Discs in clean condition do read glitch free 99%+ of the time, with properly working software and hardware.

Last edited by firage on 2017-01-06, 18:20. Edited 1 time in total.

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Reply 21 of 41, by FaSMaN

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No , sorry I miss worded that, the fact that when you try and emulated a CD-Rom drive (Fakecd for dos or daemontools etc.. for windows for instance) it cant play back the audio tracks, this made a lot of games unplayable without a burnt disk and CD writers was extremely expensive aswell as the media.... not that HDD capacity was cheap either but it was a good enough deterant especially on adventure games spanning multiple cdroms with lots of speach on the CDs.

Reply 22 of 41, by Myloch

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Any idea if data/audio subchannel data can be extracted correctly in some way? Unlike raw image, subchannel dump retries always result as different crc.

"Gamer & collector for passion, I firmly believe in the preservation and the diffusion of old/rare software, against all personal egoisms"

Reply 23 of 41, by firage

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Problematic for sure. It's fortunately pretty rare that you specifically need to extract the subchannel, apart from Securom. Securom employed a subchannel signature, but it wasn't used for much of anything otherwise. Seems to be impossible to validate good copies and distinguish surface damage there, so leaving it out is cleaner whenever possible.

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Reply 24 of 41, by lukeman3000

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Coming from someone who doesn't know a lot about this.. How do I know when iso format is appropriate or when I need to do something else, as in when there's an audio track? How does one know if there's an audio track or not?

I was looking at Alcohol or perhaps PowerISO. Any other recommendations at this point in time?

Reply 25 of 41, by Jorpho

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lukeman3000 wrote:

How does one know if there's an audio track or not?

I think the easiest way would be to use ISO Buster. The paid version has some more advanced features, but for just checking for the existence of audio tracks, the "free" version will do.

Some CD Player applications will start playing audio tracks if available, but it's hard to keep tracks of which ones can do that.

As far as making images goes, all you really need is imgburn, aside from some very exotic tasks like injecting new files. And I think DiscJuggler is still the preferred app for Dreamcast disks.

Reply 30 of 41, by Myloch

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Please AVOID to use poweriso, isobuster or ultraiso for mixed mode cdrom dumping, it will fudge indexes and gaps, use imgburn or clonecd, alcohol, nero with data/audio subchannel reading and raw mode.

"Gamer & collector for passion, I firmly believe in the preservation and the diffusion of old/rare software, against all personal egoisms"

Reply 32 of 41, by Myloch

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No. I forgot to specify I'm talking about bin+cue format. I made some tests and comparisons vs original discs. Imgburn properly handles pregaps and everything else, very good free program indeed.

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Reply 33 of 41, by Great Hierophant

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Myloch wrote:

Please AVOID to use poweriso, isobuster or ultraiso for mixed mode cdrom dumping, it will fudge indexes and gaps, use imgburn or clonecd, alcohol, nero with data/audio subchannel reading and raw mode.

Along these lines, never use Alcohol to make a BIN/CUE image, it will get the audio offsets 2 seconds wrong. Alcohol's native MDF/MDS format, or the combined MDX format, will give proper offset times for the tracks.

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Reply 34 of 41, by Stiletto

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Myloch wrote:

No. I forgot to specify I'm talking about bin+cue format. I made some tests and comparisons vs original discs. Imgburn properly handles pregaps and everything else, very good free program indeed.

The ISOBuster author is unaware of any issue. If you can write up what you've done, I'm happy to pass it along.

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Reply 36 of 41, by DosFreak

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Most DOS games are not free.
Yes there are websites where you can download game images. No you won't get any links from here.
This site does not support "abandonware". Go anywhere else on the internet for that.

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Make your games work offline

Reply 37 of 41, by gdjacobs

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If you want truly free games, two recommendations:
1) OLD NOT NEW List of Free Games
2) Watch gaming services like GOG and Humble Bundle for promotional offers

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Reply 38 of 41, by voivod

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I'm going through a process of archiving my old games to a) image file b) 1:1 cd copy.
For the a) a use ImgBurn and for the b) clonecd.

Now, I have noticed making a copy of games like Quake/Hexen (that have CD audio tracks), a new CD with audio tracks have occasional clicking and artifacts (when I listen to audio tracks) while originals are fine. I'm not sure why this is happening. I intentionally use max 8X speed for writing but it still an issue. Is this a case at all?
On the other hand I have no option to reduce read speed in CloneCD, I can only change/reduce writing speed.

Reply 39 of 41, by Jorpho

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voivod wrote:

Now, I have noticed making a copy of games like Quake/Hexen (that have CD audio tracks), a new CD with audio tracks have occasional clicking and artifacts (when I listen to audio tracks) while originals are fine. I'm not sure why this is happening. I intentionally use max 8X speed for writing but it still an issue. Is this a case at all?
On the other hand I have no option to reduce read speed in CloneCD, I can only change/reduce writing speed.

You need to determine if the clicking and artifacts are being produced during the reading process or the writing process. Are you creating an image file when you read the CD? You should be able to open it in ISOBuster and play the audio tracks from there. (ISOBuster is very versatile that way.)

What happens when you try to clone an ordinary audio CD with no data track?