You can have closed proprietary programs and have completely open standard file formats.
Sure, but can you have open free programs and closed, locked-down, proprietary formats? It's a separate issue, perhaps, but it's a very closely related one.
With difficulty. There is free software that can work with proprietary formats, but those formats have to be reverse-engineered, and if the formats change, they have to be reverse-engineered again.
Sure, but can you have open free programs and closed, locked-down, proprietary formats? It's a separate issue, perhaps, but it's a very closely related one.