Saving changes to RAW files in DPP

When you save change(s) to a Raw file in DPP without converting it to JPEG or TIFF, does the saving process do anything to degrade the original Raw file?

No, What RAW converters are doing at that point is essentially saving a "recipe" for the changes you made, and they do so without making any changes at all to the actual RAW data.
Most RAW converters save this "recipe info" in a totally separate file, similar to a thumbnail database within each folder (RSP, C1 and BB dod this)
I can't recall where DPP saves the data, but in either case, the RAW Image is not changed.

Thanks.

I noticed that the size of the raw file increase a little, so it saves the converting parameter into the raw file itself. But it seems that these modifications don't change the raw file structure since ACR and C1 still can open the file.

Thanks yb, I was thinking this was the case with DPP, but could not recall as I haven't used it in ages. DPP actually attaches the recipe to the RAW file itself, which is handy for archiving etc.
With BB, C1 and RSP, if you don';t keep your RAW files in the same folders, all that info will be lost.

Actually, with DPP you can choose between saving changes as an addition to the metadata or in a separate .vrd file.

Some people have suggested that writing to the metadata carries a risk of corrupting the file. I think this is a groundless fear; if Canon knows how to write the "as shot" settings to the file in-camera without affecting the RAW data, why wouldn't they know how to do it in DPP? BTW, when the changes are saved the "as shot" data is not overwritten and you can always return to it (Adjustment/Revert to shot settings).

tzalman wrote in post #2846737
Actually, with DPP you can choose between saving changes as an addition to the metadata or in a separate .vrd file.

Yes but it's just to bad that you have to do that manually.