MS-DOS RESTORE utility — restoring only files changed since the last backup: Which RESTORE command switch restores from drive A only those files that have been modified since the most recent backup?

Introduction / Context:DOS backup/restore workflows rely on switches to control what gets restored. Efficient incremental recovery uses a switch that returns only files changed since the last backup. Knowing these switches speeds up recovery and reduces wear on legacy media.

Given Data / Assumptions:

• The source media is drive A (typically a floppy disk).
• We want to restore files modified since the last backup, not every file.
• We are using the classic RESTORE command syntax.

Concept / Approach:

Different RESTORE switches target different behaviors. The key is recognizing that /M stands for “Modified since last backup”. Other switches (like /S for subdirectories, /N or /L) do not express this incremental-restore requirement.

Step-by-Step Solution:

Verification / Alternative check:

Contemporary DOS references document /M as “restores files modified since the last backup.” This aligns with incremental strategies common in tape and floppy workflows.

Why Other Options Are Wrong:

• /S: includes subdirectories, not modification-based selection.
• /N: typically relates to prompting or new files behavior depending on DOS version; not the modified-only filter.
• /L: used for logging or listing in some variants, not modification filtering.
• None of the above: incorrect because /M is correct.

Common Pitfalls:

Confusing backup switches between BACKUP and RESTORE; forgetting wildcard patterns; mixing up /S with selective criteria. Always confirm syntax for your DOS version.

Final Answer:

RESTORE A: . /M