Computer Architecture & Assembly Language MCQs with Answers
Practice important Computer Architecture & Assembly Language MCQs with answers and explanations.
Chapter: 13
Q301:
Which service in DOS is used to read from a file?
A. INT 21h, AH=3Dh
B. INT 21h, AH=3Fh
C. INT 21h, AH=40h
D. INT 21h, AH=41h
Correct Answer:
B
Chapter: 13
Q302:
What happens if the cmp ax, cx instruction in the file comparison program finds a mismatch?
A. Program exits
B. Files are declared identical
C. Files are declared different
D. Program loops back
Correct Answer:
C
Chapter: 13
Q303:
What does the BIOS Parameter Block (BPB) provide?
A. Boot sector information
B. Storage medium parameters
C. Memory allocation details
D. Interrupt vector table
Correct Answer:
B
Chapter: 13
Q304:
How many FAT copies does the BPB example contain?
A. 1
B. 2
C. 4
D. 8
Correct Answer:
A
Chapter: 13
Q305:
What value is stored in the media descriptor byte in the example BPB?
A. 0xF8
B. 0xF0
C. 0xE0
D. 0xD0
Correct Answer:
A
Chapter: 13
Q306:
What is the purpose of the mov ah, 0x4A instruction in the multitasking TSR caller program?
A. Resize memory
B. Load a program
C. Free memory
D. Allocate memory
Correct Answer:
A
Chapter: 13
Q307:
In the file comparison program, what does the int 0x21 instruction with AH=3E do?
A. Open a file
B. Close a file
C. Read from a file
D. Write to a file
Correct Answer:
B
Chapter: 13
Q308:
What is the significance of the 0x80 value used in the mov cl, [0x80] instruction?
A. Indicates command tail length
B. Indicates file handle
C. Indicates buffer size
D. Indicates memory address
Correct Answer:
A
Chapter: 13
Q309:
In DOS, what does the error flag (CF) being set indicate when using memory-related interrupts?
A. Successful operation
B. An error occurred
C. Program termination
D. System reboot
Correct Answer:
B
Chapter: 13
Q310:
Which segment register is typically used with the int 0x21 service to point to the program name?
A. DS
B. ES
C. SS
D. CS
Correct Answer:
A
Chapter: 13
Q311:
What is stored at the start of the device driver file?
A. BPB
B. Header
C. FAT
D. Data sector
Correct Answer:
B
Chapter: 13
Q312:
How does a DOS device driver differentiate between character and block devices?
A. Using bit 15 in the device attribute word
B. Using the FAT
C. Using the BPB
D. Using the file system interface
Correct Answer:
A
Chapter: 13
Q313:
What does the instruction int 0x21, ah=4B do in the multitasking TSR caller program?
A. Load and execute a program
B. Resize memory
C. Allocate memory
D. Free memory
Correct Answer:
A
Chapter: 14
Q314:
What is the main difference between serial and parallel port communication?
A. Bits are sent one by one
B. Bytes are sent one by one
C. Bytes are sent in parallel
D. Bits are sent in parallel
Correct Answer:
A
Chapter: 14
Q315:
What type of connector is used for a serial port?
A. DB-25
B. DB-9
C. RJ-45
D. USB
Correct Answer:
B
Chapter: 14
Q316:
How many wires are sufficient for full duplex serial communication?
A. One
B. Two
C. Three
D. Four
Correct Answer:
C
Chapter: 14
Q317:
What is the standard format used for serial port communication?
A. RS422
B. RS485
C. RS232
D. USB
Correct Answer:
C
Chapter: 14
Q318:
What is the purpose of the start bit in RS232 communication?
A. End data transmission
B. Indicate an error
C. Start data transmission
D. Parity check
Correct Answer:
C
Chapter: 14
Q319:
How many data bits can be used in RS232 communication?
A. 4 to 7
B. 5 to 8
C. 7 to 9
D. 6 to 9
Correct Answer:
B
Chapter: 14
Q320:
What BIOS service initializes the serial port?
A. INT 14 - AH = 01h
B. INT 14 - AH = 02h
C. INT 14 - AH = 03h
D. INT 14 - AH = 00h
Correct Answer:
D