Ch 09: Software Interrupts and DOS/BIOS Services

Covers IVT structure (256 vectors x 4 bytes each = 1KB), pushing flags and CS:IP during interrupt invocation, hooking existing software interrupts, and invoking DOS function calls for disk and character I/O.

174 Questions174 MCQs0 Short Questions0 Long Questions

🎯 Exam Practice Papers

CS401 - Computer Architecture and Assembly Language Programming Examination Practice

Timed practice exam simulation for CS401 - Computer Architecture and Assembly Language Programming.

Showing 61 – 70 of 174 Questions

Page 7 of 18

Q61

❓ MCQ📘 CS401📑 Lec 9🏷️ 9.1. Interrupt Handling (IRQ 4 Serial Port COM 1 Assignment)Easy🔁⭐💡📄🎓VU🏛️VU

Which hardware IRQ line is assigned to serial communications port COM 1?

A.IRQ 4
B.IRQ 5
C.IRQ 6
D.IRQ 7

Q62

❓ MCQ📘 CS401📑 Lec 9🏷️ 9.1. Interrupt Handling (8259 PIC Control Port 0x20)Easy🔁⭐💡📄🎓VU🏛️VU

In the 8259 Programmable Interrupt Controller (PIC), which I/O port address is referred to as the Control / Command Port?

💻 assembly Snippet

mov al, 0x20
out 0x20, al ; Sends EOI command to 8259 control port 0x20

A.19
B.20
C.21
D.22

Q63

❓ MCQ📘 CS401📑 Lec 9🏷️ 9.1. Interrupt Handling (8259 PIC Eight Inputs and One Output Signal)Easy🔁⭐💡📄🎓VU🏛️VU

Regarding pin interface signals, a single 8259 Programmable Interrupt Controller (PIC) chip possesses __________.

A.One input signals and eight output signals
B.One input signal and one output signal
C.Eight input signals and one output signals
D.Eight input signals and eight output signals

Q64

📝 Short Q📘 CS401📑 Lec 9🏷️ 9.1. Interrupt Handling (INT 1 Trap Exception Purpose)Easy🔁⭐💡📄🎓VU🏛️VU

For what specific purpose is the x86 hardware interrupt vector `INT 1` reserved in system architecture?

💻 assembly Snippet

; INT 1 Debug Exception
; Triggered automatically after each instruction when TF = 1

Q65

📝 Short Q📘 CS401📑 Lec 9🏷️ 9.1. Timer Interfacing (8254 PIT 1 ms Timer Frequency Configuration)Medium🔁⭐💡📄🎓VU🏛️VU

Write x86 assembly language instructions to configure the 8254 PIT (Programmable Interval Timer) Channel 0 to generate interrupts at a frequency of 1 millisecond (1000 Hz).

💻 assembly Snippet

mov al, 0x36
out 0x43, al
mov ax, 1193
out 0x40, al
mov al, ah
out 0x40, al

Q66

📝 Short Q📘 CS401📑 Lec 9🏷️ 9.1. Interrupt Handling (INT 1 Trap / Single-Step Vector)Easy🔁⭐💡📄🎓VU🏛️VU

For what specific purpose is the x86 hardware interrupt vector `INT 1` reserved?

💻 assembly Snippet

; INT 1 Debug Exception
; Triggered automatically after each instruction when TF = 1

Q67

❓ MCQ📘 CS401📑 Lec 9🏷️ 9.1. Interfacing and Peripherals (DB-25 Parallel Port Ground Pins 18-25)Easy🔁⭐💡📄🎓VU🏛️VU

On a standard DB-25 parallel printer port connector, which range of pin numbers is connected to electrical ground?

A.10-18
B.18-25
C.25-32
D.32-39

Q68

❓ MCQ📘 CS401📑 Lec 9🏷️ 9.1. DOS and BIOS Services (INT 21h Service 01H Character Input)Easy🔁⭐💡📄🎓VU🏛️VU

DOS `INT 21h` Service `01H` reads a single character from standard input with screen echoing. In which register is the ASCII character code returned?

💻 assembly Snippet

mov ah, 01h ; Service 01h: Read character with echo
int 21h     ; Character returned in AL

A.AL
B.BL
C.CL
D.BH

Q69

❓ MCQ📘 CS401📑 Lec 9🏷️ 9.1. Interfacing and Peripherals (DB-9 Serial Port Pinout: Carrier Detect Pin 1)Easy🔁⭐💡📄🎓VU🏛️VU

On a standard 9-pin DE-9 / DB-9 serial RS-232 connector, which pin number is assigned to the CD (Carrier Detect) signal line?

Q70

❓ MCQ📘 CS401📑 Lec 9🏷️ 9.1. Interfacing and Peripherals (DB-9 Serial Port Pinout: Signal Ground Pin 5)Easy🔁⭐💡📄🎓VU🏛️VU

On a standard 9-pin DE-9 / DB-9 serial RS-232 connector, which pin number is assigned to Signal Ground (GND)?

Ch 09: Software Interrupts and DOS/BIOS Services

CS401 - Computer Architecture and Assembly Language Programming Examination Practice

Mid Term Examination

Final Term Examination

CS401 - Computer Architecture and Assembly Language Programming Examination Practice

Mid Term Examination

Final Term Examination

📖 Related CS401 - Computer Architecture and Assembly Language Programming Curriculum Units