That works, but has some pitfalls. You're fine if:
- the disk can still be read: CDs and DVD deteriorate over time, and file systems could change...
- the software can still be executed (not sure a program written for the original Apple Mackintosh would run on the latest Apples, I'm sure it won't)
I suppose you refer to dcraw, so that's for the moment a rather safe bet (the source code is available, rather straightforward and in a standard language).
It might not work as well for proprietary software.