Q1: When two devices in the system want to use the same IRQ line then what will happen?
Answer: An IRQ Conflict
Q2: Hard disk MBR (Master Boot Record) is of size:
Answer: 512 bytes
Q3: Which of the following IRQs is connected to serial port COM 2?
Answer: IRQ 3
Q4: The first sector on hard disk contains the:
Answer: Partition table
Q5: In programmable interrupt controller which port is referred as a control port?
Answer: 20
Q6: Which of the following IRQs is used by the parallel port?
Answer: IRQ 7
Q7: The programmable interval timer (PIT) has input frequency of:
Answer: 1.193 MHz
Q8: CX register mostly used as a:
Answer: Counter register
Q9: The input frequency of PIT is:
Answer: Fixed
Q10: Thread registration code initializes PCB and adds it to linked list so that the:
Answer: Scheduler will give it a turn
Q1: INT13 BIOS disk services uses which register to return ‘error code’?
Answer: CF
Q2: Operating system organizes data in the form of:
Answer: File
Q3: Instruction that decrements SP by 2 and transfers a word to top of stack:
Answer: PUSH
Q4: Non-maskable interrupt:
Answer: INT 0
Q5: Maximum parameters a subroutine can receive:
Answer: 7
Q6: When the operand of DIV is 16-bit, dividend stored in:
Answer: AX (or DX:AX if required)
Q7: COM2 connected with:
Answer: IRQ 3
Q8: Parallel port connector:
Answer: DB-25
Q9: Instruction to call software interrupt:
Answer: INT interrupt_number
Q10: INT 0x13 service 0x03 is used to:
Answer: Read disk sector
Q1: Data bus is:
Answer: Bi-directional
Q2: PUSH increments SP by 2?
Answer: False
Q3: Peripheral address space selected by which instruction?
Answer: IN
Q4: Creation of threads:
Answer: Both (Static & Dynamic)
Q5: IRQ used by parallel port:
Answer: IRQ 7
Q6: Priority of IRQ 0:
Answer: Highest
Q7: Number of pins in parallel port:
Answer: 25
Q8: Interrupt call loads new values in:
Answer: CS, IP, Flags
Q9: All registers and stacks are saved in:
Answer: Multitasking
Q10: In 9-pin DB connector, which pin is assigned to TD:
Answer: Pin 2
Q1: Assembly language is not a low-level language:
Answer: False
Q2: In COM file first command stored at offset:
Answer: 0x100
Q3: Address always goes from:
Answer: Processor to memory
Q4: Source register in OUT instruction:
Answer: AL or AX
Q5: By default CS is associated with:
Answer: IP
Q6: Pins of parallel port grounded:
Answer: 18–25
Q7: Instruction mov word [es:160], 0x1230, 30 represents:
Answer: 0
Q8: On executing 0x21 0x3D, if file cannot be opened:
Answer: CF will contain 1
Q9: Cascading interrupt:
Answer: IRQ 2
Q10: Execution of mov word [es:160], 0x1230 prints character at:
Answer: First column of second row
Q1: RET instruction takes:
Answer: 1 argument (optional, depends on CALL)
Q2: In STOSB, SI is incremented by:
Answer: 1
Q3: CMPS instruction subtracts source from destination:
Answer: DS:SI from ES:DI
Q4: Assembler statement:
Answer: Assembler converts mnemonics to corresponding OPCODE
Q5: OPCODE BB, Mov AX, 336 (hex 0x150) in little endian:
Answer: 0xBB5001
Q6: MOV AX, 5 number of operands:
Answer: 2
Q7: Max parameters a subroutine can receive:
Answer: 7
Q8: CX register used as:
Answer: Counter
Q9: Address returned by iAPX88 addressing mechanisms:
Answer: Effective address
Q10: 16-bit number divided by 8-bit, dividend in:
Answer: AX
Q11: Left-shift operation, leftmost bit:
Answer: Will go into CF
Q12: Decimal 35 after left-shift by 2 bits:
Answer: 140
Q13: Divide overflow interrupt type:
Answer: Processor exception
Q14: SCAS instruction dominant operation:
Answer: Subtraction
Q15: REP instruction affects which flag?
Answer: No flags
Q16: Reason string instructions used in 8088:
Answer: Reduction in code size and speed
Q1: Physical address of stack obtained by:
Answer: SS:SP combination
Q2: After RET, SP:
Answer: Incremented by 2
Q3: Second byte in word for screen location holds:
Answer: Character color
Q4: REP always:
Answer: Decrement CX by 1
Q5: Basic function of SCAS:
Answer: Compare
Q6: Index registers store:
Answer: Address
Q7: Bits of which work independently:
Answer: Flags register
Q8: Convert digit to ASCII:
Answer: Add 0x30
Q9: 32-bit number divided by 16-bit, quotient:
Answer: 16 bits
Q10: 16-bit divided by 8-bit, quotient:
Answer: AX
Q11: SCAS dominant operation:
Answer: Subtraction
Q12: AX = -2, BX = 2, CMP AX, BX JA label:
Answer: Jump will be taken
Q13: Execution of mov word [ES:160], 0x1230 prints “0” at:
Answer: First column of second row
Q14: String processing from high to low addresses:
Answer: DF is set
Question No: 15 – ADC has Operand(s)
Answer: 2 Two
Question No: 16 – Which bit of the attributes byte represents the red component of background color?
Answer: 4
Q1 – Bit of attributes byte for blue component of foreground color
Answer: 1
Q2 – Clear screen operation initializes video memory to
Answer: 0720
Q3 – DIV operand 16-bit → implied dividend
Answer: 32-bits
Q4 – Pair of registers used in string instruction
Answer: DI and SI
Q5 – FAT32 directory entry in DOS
Answer: 32 bytes
Q6 – Register for interrupt service number
Answer: AX
Q7 – DB9 pin for RD (Received Data)
Answer: 2
Q8 – COM file maximum command line parameters
Answer: 127 bytes
Q9 – Access DOS services
Answer: Int 0x21
Q10 – DB9 pin for signal ground
Answer: 5
Q11 – BPB stands for
Answer: BIOS Parameter Block
Q12 – INT 13 returns error flag in
Answer: CF
Q13 – First sector on hard disk contains
Answer: Partition table
Q14 – OS organizes data as
Answer: File
Q15 (DB9 TD) – Pin for transmitted data
Answer: 3
Q16 – Device driver major categories
Answer: 2
1 – BL = 5, after right shift
Answer: 2
2 – 8×16 font stored in
Answer: 16 bytes
3 – DOS input buffer: number of chars read
Answer: Second byte
4 – IRQ0 priority
Answer: Highest
5 – Thread registration code → gives turn
Answer: Scheduler
6 – Traditional calling conventions
Answer: 2
7 – VESA VBE 2.0 standard for
Answer: High Resolution Mode
8 – Clear direction flag instruction
Answer: CLD
9 – STOSW: DI cleared, SI
Answer: Incremented by 2
10 – Debugging interrupt with trap flag
Answer: INT 1
11 – Arithmetic overflow interrupt
Answer: INT 4
12 – IRQ refers to
Answer: Eight input signals
13 – IRQ for keyboard
Answer: 1
14 – IRQ for sound card
Answer: 5
15 – IRQ for floppy disk
Answer: 6
16 – IRQ with highest priority
Answer: Timer IRQ
17 – Parallel port ground pins
Answer: 18–25
18 – Physical address of IDT stored in
Answer: IDTR
19 – RET 2 execution
Answer: SP incremented by 2
20 – CX register is
Answer: Count register
21 – OUT instruction source register
Answer: AL or AX
22 – DB9 DSR pin
Answer: 6
23 – IRQ conflict if two devices use same IRQ
Answer: IRQ conflict
24 – VESA 16-bit color per pixel ratio
Answer: 5:5:5
25 – Division by zero interrupt
Answer: Interrupt 0
SAR instruction (Q1) – MSB retains original value
RETF offset (Q2) – IP
INT routine (Q3) – ISR
COM first instruction offset (Q4) – 0x0100
Far jump (Q5) – Absolute
Memory to memory data movement (Q6) – String instructions
RET 2 (Q7) – SP incremented by 4
DIV forms (Q8) – Two forms
DIV operand 16-bit (Q9) – 32-bit dividend
MOVS execution (Q10) – SI and DI updated
Push on stack (Q11) – SP decremented by 2
Divide overflow (Q12) – Divide overflow error
Video memory higher address (Q13) – Attribute byte
Video window (Q14) – mov AX,0xb800 mov ES, AX
Video memory screen location (Q15) – Two bytes
mov word [ES:0],0x0741 – Background color: Red
Registers not true (Q1) – Their operation is very much like memory → FALSE
move [bp], al segment (Q2) – Stack segment
RCR instruction 16-bit word (Q3) – 17-bit rotation
8088 stack (Q4) – Word-sized elements
8×16 font (Q5) – 16 bytes
INT 10 services (Q6) – BIOS video
IRQ0 priority (Q7) – Highest
Thread function calls (Q8) – Local variables
Prevalent calling conventions (Q9) – 3
DB9 DSR pin (Q10) – 6
DB9 CTS pin (Q11) – 8
DB9 CD pin (Q12) – 1
DB9 RD pin (Q13) – 2
Device attribute word (Q14) – Bit 15
Video services categories (Q15) – 3
STOSB DF clear (Q16) – SI incremented by 1
Signal process (Q17) – Hand-shaking
Special interrupt (Q18) – Debug interrupt
Timer IRQ (Q19) – IRQ 0
Arithmetic overflow (Q20) – INT 4
Serial COM2 (Q21) – IRQ 3
End of Interrupt (Q22) – PIC
OUT source register (Q23) – AL or AX
PIC enable/disable port (Q24) – 21
Parallel port pins (Q25) – 25
Parallel port ground pins (Q26) – 18–25
Binary shift 35 >> 2 (Q27) – 8? Actually 35 >> 2 = 8 (35/4)
32-bit address max memory (Q28) – 4GB
NASM imported/exported symbol (Q29) – External directive, Global directive
Single step interrupt (Q30) – INT 1