What are the functions of DOS? Write two external DOS commands with syntax.

DOS (Disk Operating System) is a single-user, command-line OS (e.g. MS-DOS). It manages files and hardware through typed commands without a GUI.

Functions:

1. File management — Create, copy, delete, rename files and folders.
2. Memory and device control — Manages RAM and I/O via drivers.
3. Program execution — Loads and runs .exe/.bat programs.
4. Disk maintenance — Format, check disk, directory listing.

External commands (separate .exe/.com files, unlike internal DIR/CLS):

1. XCOPY — bulk copy with subfolders:

XCOPY C:\Office D:\Backup /S /E

Copies all files plus empty subfolders from Office to Backup.

1. FORMAT — prepare disk:

FORMAT D: /FS:NTFS

Erases D: and creates NTFS file system. Use cautiously — data is lost.

Other examples examiners accept: CHKDSK, DISKCOPY, TREE.