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Should I keep my .raw files after I get a good image?

Posted: Mon Aug 02, 2021 11:53 pm
by Alex
When I image a floppy I always do a stream preservation first and then output to the correct format. I know .raw files contains "hidden" information maybe hidden for copy protection but if the game/software does not use protection, what's the point in keeping the raw files? What do you do for your collection?

Re: Should I keep my .raw files after I get a good image?

Posted: Tue Aug 03, 2021 3:17 pm
by mr.vince
We keep them. Always. It's what's on the disk, not just some rendition of it.

Re: Should I keep my .raw files after I get a good image?

Posted: Tue Aug 03, 2021 11:11 pm
by SomeGuy
Preservation stream/.raw dumps can be used to help prove the "authenticity" of the data on the disk. For example, on MFM disks the kryoflux software can show if a sector was written to by a user after a disk was professionally mastered at a factory.

If a disk was professionally mastered, then preservation streams can also contain hidden "mastering" data that may include info like the time it was written, the serial number of the unit that wrote it, the location and company that did it, revision number of the software image, and so on.

But more importantly, it can be used to recover data. I can't even begin to count the number of times that I have downloaded an .IMG file, discovered a damaged sector, and wished I had a preservation stream dump to analyze, as there is often a high likelihood that I could have pulled out the correct data in various ways.

Of course, if it just some data disk, and you are satisfied that you have the results you want (for example a disk image containing a zip file that tests OK) then do whatever you want.

Re: Should I keep my .raw files after I get a good image?

Posted: Wed Aug 04, 2021 1:27 am
by Alex
Thanks for the insight. I was wondering if the GUI is giving visual input when something interesting is on the disk (like a copy protection). I think a yellow N on the 6/12th (depending of 40/80 tracks drive) track of a Sierra disk means some kind of copy protection.

Re: Should I keep my .raw files after I get a good image?

Posted: Wed Aug 04, 2021 8:29 pm
by SomeGuy
There are many, many different kinds of copy protections. Many of those protections went to great lengths to keep people from finding the protected bits.

Warnings about different numbers of sectors, different sized sectors, or anything that deviates from standards, may be a hint as to copy protection.

But without program analysis and testing, it is only a hint. Some copy protected disks look like 100% standard disks to the Kryoflux software. In some other cases, odd geometry may actually be normal for a disk.

Re: Should I keep my .raw files after I get a good image?

Posted: Sat Aug 07, 2021 7:33 pm
by mr.vince
Especially if you don't know for sure... keep the raw streams. Hence our recommendation.