Disk Operating System (DOS) MCQ Questions & Answers | Computer Science

In Disk Operating System (DOS), the DEL command is used to delete files. When you enter "del filename" at the command prompt in DOS, it deletes the specified file from the current directory.

Option B, "Delete directory," is not done with the DEL command in DOS. To delete a directory, the command is typically "rmdir" or "rd" in DOS.
Option C, "Delete labels," is not a function of the DEL command in DOS.
Option D, "Delete contents of file," is not the primary purpose of the DEL command, which deletes entire files rather than just their contents.

Therefore, the correct answer is Option A: Delete files.

In Disk Operating System (DOS), the command used to ask for confirmation before deleting files is Option C: Del ./p. The "/p" switch prompts the user to confirm each deletion before proceeding, ensuring that files are not deleted accidentally.

Option A, "Deltree," deletes directories and their contents recursively but does not prompt for confirmation in standard DOS commands.
Option B, "Deltree /f," is not a valid switch for prompting confirmation in DOS commands.
Option D, "Erase .," is used to delete all files without prompting for confirmation.

Therefore, the correct answer is Option C: Del ./p.

The correct statement among the options provided is Option C: 1 millisec = 10 ^ -3 sec. This statement correctly defines the relationship between milliseconds and seconds, indicating that one millisecond is equal to one-thousandth of a second.

Option A, "Directories can be kept inside a file," is incorrect. Directories (folders) contain files and other directories but cannot themselves be stored inside a single file in typical file systems.
Option B, "Files cannot be kept inside a directory," is also incorrect. Files are typically stored within directories (folders) in file systems.

Therefore, the correct answer is Option C: 1 millisec = 10 ^ -3 sec.

In Disk Operating System (DOS), the CHKDSK command is used to find and repair disk errors, including locating bad sectors on the disk. Therefore, the correct option is Option A: Disk’s bad portion. CHKDSK analyzes the file system for errors, checks the disk surface for physical errors (bad sectors), and ensures the integrity of file and directory structures.

Option B, "Occupied space," and Option C, "Free space," are not functionalities of CHKDSK. CHKDSK primarily focuses on disk integrity and error-checking rather than space allocation.

Therefore, the correct answer is Option A: Disk’s bad portion.

In Disk Operating System (DOS), the DIR command is used to display a list of files in a directory. When you enter "dir" at the command prompt in DOS, it lists all the files and directories present in the current directory.

Option B, "Display contents of files in directory," is not correct. The DIR command does not display the contents of files; it only lists their names, sizes, and other details.
Option C, "Display type of files in a sub directory," is also not correct. The DIR command lists files and directories but does not categorize them by type within a subdirectory.

Therefore, the correct answer is Option A: Display a list of files in a directory.

In MS-DOS, if you want to recover a recently deleted file, you can use the command Option C: UNDELETE. This command allows you to recover files that have been recently deleted from the disk, provided they have not been overwritten by other data.

Option A, "DO NOT DELETE," and Option B, "NO DELETE," are not valid commands in MS-DOS.
Option D, "ONDELETE," is not a command in MS-DOS for recovering deleted files.

Therefore, the correct answer is Option C: UNDELETE.

In Disk Operating System (DOS), to copy the file command.com from drive C: to drive A:, the correct command syntax is essential.

Option A: Drive c: copy drive a:\command.com. This option is incorrect because it does not follow the correct syntax for the copy command in DOS.

Option B: C:A: copy command.com. This option is incorrect because it does not specify the source and destination paths correctly.

Option C: Copy c:\command.com a:. This option is correct as it specifies the source file c:\command.com and the destination drive a: using the copy command in DOS.

Option D: Both b and c. This option is incorrect because Option B is incorrect. Option C alone provides the correct syntax.

Therefore, the correct answer is Option C: Copy c:\command.com a:. This command will copy the file command.com from drive C: to drive A: in DOS.

In MS-DOS, the key used to get the previous command used is Option A: F3. Pressing F3 on the keyboard while working in the MS-DOS prompt retrieves the last command entered, allowing you to quickly repeat it without typing it again.

Option B, "F1," typically displays help information in MS-DOS applications.
Option C, "F6," and Option D, "F9," do not have specific functionalities related to retrieving previous commands in MS-DOS.

Therefore, the correct answer is Option A: F3.

In Disk Operating System (DOS), FAT stands for Option C: File Allocation Table. The File Allocation Table is a crucial part of the file system used by DOS and other operating systems to manage and allocate space on storage devices such as hard drives and floppy disks.

Option A, "File Accommodation Table," and Option B, "File Access Tape," are not correct terms related to FAT in DOS.
Option D, "File Activity Table," is also not a correct term related to FAT.

Therefore, the correct answer is Option C: File Allocation Table.

In Disk Operating System (DOS), the xcopy command is used to copy directories including subdirectories. It can copy entire directory trees from one location to another, preserving the directory structure and all files within those directories.

Option A, "Individual files or group of files," is correct as xcopy can also copy individual files or groups of files.
Option C, "To diskette of a different capacity," is also correct as xcopy can copy files to different types of disks, including diskettes of varying capacities.

Therefore, the correct answer is Option D: All of above.