One control against accidental software deletion is to save all old versions of a program. Of course, this control is prohibitively expensive in terms of cost of storage. Suggest a less costly control against accidental software deletion. Is your control effective against all possible causes of software deletion? If not, what threats does it not cover?

What will be an ideal response?

Save incremental copies—only the changes since the last change. Equivalently, save a “transaction journal” of changes since last full backup. Develop a configuration management approach to save code necessary tocreate a new version from the old.