CAOFINALQUIZ

Question 1

Which interrupt service is used to create a subdirectory?

a) INT 21H / 3CH
b) INT 21H / 39H
c) INT 21H / 3AH
d) INT 21H / 56H

Answer 1

INT 21H / 39H

Question 2

Which of the following is a requirement for deleting a subdirectory using INT 21H / 3AH?

a) The subdirectory must not contain any files.
b) The subdirectory must be hidden.
c) The subdirectory must be read-only.
d) The subdirectory must have a volume label.

Answer 2

he subdirectory must not contain any files.

Question 3

What is the purpose of INT 21H / 56H?

a) To rename files or directories.
b) To create a new file.
c) To open a file.
d) To delete a file.

Answer 3

To rename files or directories.

Question 4

Which file attribute indicates a file is a “hidden file”?

a) 0
b) 1
c) 3
d) 5

Answer 4

1

Question 5

What does the CX register represent when using the INT 21H / 3CH service?

a) File handle
b) File attribute
c) Error status
d) Directory path

Answer 5

File attribute

Question 6

Which attribute is represented by bit 4 in a file attribute?

a) Archive file
b) Read-only file
c) Subdirectory
d) Volume label

Answer 6

Subdirectory

Question 7

Which interrupt service is used to change a file’s attributes?

a) INT 21H / 43H
b) INT 21H / 3DH
c) INT 21H / 41H
d) INT 21H / 39H

Answer 7

INT 21H / 43H

Question 8

What access mode value allows both reading and writing to a file?

a) 0
b) 1
c) 2
d) 3

Answer 8

2

Question 9

Which interrupt service opens a file?

a) INT 21H / 3DH
b) INT 21H / 3EH
c) INT 21H / 5BH
d) INT 21H / 41H

Answer 9

INT 21H / 3DH

Question 10

What is required to close a file using INT 21H / 3EH?

a) File path
b) File attribute
c) File handle
d) Directory path

Answer 10

File handle

Question 11

Which directive is used to define the beginning of a procedure in assembly language?

a) PROC
b) ENDP
c) CALL
d) LOOP

Answer 11

PROC

Question 12

What is the purpose of the CALL instruction in assembly language?

a) To end a procedure
b) To define a loop
c) To execute a procedure
d) To define a stack

Answer 12

To execute a procedure

Question 13

What register is decremented in a loop instruction?

a) AX
b) CX
c) DX
d) BX

Answer 13

CX

Question 14

Which stack instruction places data onto the stack segment?

a) POP
b) PUSH
c) LOOP
d) CALL

Answer 14

PUSH

Question 15

Which stack instruction retrieves data from the stack?

a) POP
b) PUSH
c) LOOP
d) CALL

Answer 15

POP

Question 16

How many times does the loop execute if CX = 10?

a) 0
b) 10
c) 11
d) Unlimited

Answer 16

10

Question 17

What happens to CX when the LOOP instruction executes?

a) It is incremented.
b) It is reset to 0.
c) It is decremented.
d) It remains unchanged.

Answer 17

It is decremented.

Question 18

In the sample program, what is the value pushed onto the stack using the instruction PUSH AX?

a) The value of the AX register.
b) The value of the BX register.
c) The value of the CX register.
d) The value of the DX register.

Answer 18

he value of the AX register.

Question 19

What is the purpose of the RET instruction in a procedure?

a) To return control to the calling program.
b) To define the end of the program.
c) To increment the CX register.
d) To loop back to the start of a procedure.

Answer 19

To return control to the calling program.

Question 20

Which register is used to point to a string in memory for INT 21H services?

a) BX
b) CX
c) DX
d) AX

Answer 20

DX

Question 21

What is the purpose of INT 21H / 39H?

a) To create a file in the current directory
b) To create a subdirectory
c) To delete a file from a directory
d) To rename a file or directory

Answer 21

To create a subdirectory

Question 22

What does the INT 21H / 3AH service do?

a) Renames a directory
b) Deletes a subdirectory
c) Retrieves file attributes
d) Changes the current directory

Answer 22

Deletes a subdirectory

Question 23

What is the function of INT 21H / 56H?

a) To delete a file
b) To open a file
c) To rename a file or directory
d) To create a file

Answer 23

To rename a file or directory

Question 24

Which file attribute allows only viewing but not editing the file?

a) Hidden file
b) Archive file
c) Read-only
d) System file

Answer 24

Read-only

Question 25

What does the CX register specify when creating a file using INT 21H / 3CH? a) The file size b) The file attributes c) The file's content d) The file handle

Answer 25

The file attributes

Question 26

What is an ASCIIZ string? a) A string terminated by a null character (00H) b) A string containing only ASCII characters c) A string with a predefined length d) A string that uses wildcards

Answer 26

A string terminated by a null character (00H)

Question 27

What does INT 21H / 41H accomplish? a) Creates a file b) Deletes a file c) Retrieves file attributes d) Changes file permissions

Answer 27

Deletes a file

Question 28

What is the function of INT 21H / 3BH? a) Creates a subdirectory b) Changes the current directory c) Deletes a subdirectory d) Renames a file

Answer 28

Changes the current directory

Question 29

Which of the following modes of accessing files allows both reading and writing? a) Mode 0 b) Mode 1 c) Mode 2 d) Mode 3

Answer 29

Mode 2

Question 30

What is the role of INT 21H / 3EH? a) To close a file b) To open a file c) To create a subdirectory d) To rename a file

Answer 30

To close a file

Question 31

What directive defines the beginning of a procedure in assembly language? a) ENDP b) CALL c) PROC d) RET

Answer 31

PROC

Question 32

What is the purpose of the ENDP directive in assembly language? a) To end a loop b) To end a procedure c) To push a value onto the stack d) To return from a procedure

Answer 32

To end a procedure

Question 33

What is the primary purpose of the PUSH instruction? a) To end a procedure b) To decrement the CX register c) To place data onto the stack d) To retrieve data from the stack

Answer 33

To place data onto the stack

Question 34

What happens to the CX register during a LOOP instruction? a) It is reset to 0 b) It is incremented by 1 c) It is decremented by 1 d) It is unchanged

Answer 34

It is decremented by 1

Question 35

Which INT 21H function is used to create a file only if it does not already exist? a) 3CH b) 5BH c) 3AH d) 39H

Answer 35

5BH

Question 36

What attribute must be excluded when deleting a file using INT 21H / 41H? a) Hidden b) Read-only c) Archive d) System

Answer 36

Read-only

Question 37

What is required to change a directory using INT 21H / 3BH? a) File handle in BX b) ASCIIZ string in DS:DX c) Mode value in AL d) CX register set to 0

Answer 37

ASCIIZ string in DS:DX

Question 38

What error will occur if an attempt is made to delete a non-empty directory using INT 21H / 3AH? a) Directory not found b) Access denied c) Directory not empty d) Invalid file handle

Answer 38

Directory not empty

Question 39

Which INT 21H service is responsible for retrieving or modifying a file's attributes? a) 3CH b) 39H c) 43H d) 56H

Answer 39

43H

Question 40

What is the difference between INT 21H / 3CH and INT 21H / 5BH? a) 3CH can overwrite existing files, while 5BH cannot b) 3CH is used for directories, while 5BH is for files c) 5BH requires a file handle, while 3CH does not d) 5BH supports wildcards, while 3CH does not

Answer 40

3CH can overwrite existing files, while 5BH cannot

Question 41

What does the CX register signify when creating a file using INT 21H / 3CH? a) File handle b) File attributes c) Directory path length d) File size

Answer 41

File attributes

Question 42

Which file attribute indicates that the file is used by the operating system? a) Hidden file b) Archive file c) System file d) Subdirectory

Answer 42

System file

Question 43

What attribute is used to mark files that have been modified and need backup? a) Archive file b) Read-only file c) Hidden file d) Volume label

Answer 43

Archive file

Question 44

Which bit in the file attribute byte signifies a subdirectory? a) Bit 0 b) Bit 3 c) Bit 4 d) Bit 5

Answer 44

Bit 4

Question 45

What is the purpose of the RET instruction in assembly? a) Returns control from a procedure b) Jumps to a label c) Calls another procedure d) Ends a program

Answer 45

Returns control from a procedure

Question 46

Which directive specifies the starting point of an assembly language program? a) ORG b) PROC c) END d) START

Answer 46

ORG

Question 47

What is the significance of the directive .MODEL SMALL? a) Sets the stack size to small b) Specifies that code and data fit within a single 64KB segment each c) Limits the program to 16-bit registers d) Enables small memory allocation

Answer 47

Specifies that code and data fit within a single 64KB segment each

Question 48

What does the directive .CODE indicate in assembly? a) Start of a procedure b) Start of the code segment c) Declaration of variables d) End of a program

Answer 48

Start of the code segment

Question 49

What happens if a POP instruction is executed on an empty stack? a) Data corruption b) Overflow error c) Underflow error d) No effect

Answer 49

Underflow error

Question 50

Which register is modified when data is pushed onto the stack? a) CX b) SP c) DX d) AX

Answer 50

SP

Question 51

What is the default behavior of the stack when data is pushed? a) It increments SP b) It decrements SP c) It stores data at the top of the stack and leaves SP unchanged d) It swaps SP and BP

Answer 51

It decrements SP

Question 52

How does the PUSH AX instruction differ from PUSH DX? a) PUSH AX requires a 32-bit processor b) PUSH AX stores the value of AX, while PUSH DX stores the value of DX c) PUSH AX can only be used with memory, not registers d) PUSH AX uses a different segment than PUSH DX

Answer 52

PUSH AX stores the value of AX, while PUSH DX stores the value of DX

Question 53

Which register controls the number of iterations in a LOOP instruction? a) SP b) DX c) CX d) BX

Answer 53

CX

Question 54

What happens when the CX register reaches zero in a LOOP instruction? a) The loop restarts b) The program exits c) The loop terminates d) An error occurs

Answer 54

The loop terminates

Question 55

What is the purpose of the LOOP label instruction? a) Executes the labeled code only once b) Transfers control unconditionally to a label c) Repeats the code at the label until CX = 0 d) Decrements AX and jumps to a label

Answer 55

Repeats the code at the label until CX = 0