CS401 Finalterm Paper 4

CS401

finalterm Paper 2010 spring

Question No: 1 ( Marks: 1 ) - Please choose one
The physical address of the stack is obtained by
SS:SI combination
SS:SP combination
ES:BP combination
ES:SP combination
Question No: 2 ( Marks: 1 ) - Please choose one
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Value of AH in the write Graphics pixel service is
0Ch
0Bh
1Ch
2Ch
Question No: 3 ( Marks: 1 ) - Please choose one
Threads can have function calls, parameters and __________ variables.
global
local
legal
illegal
Question No: 4 ( Marks: 1 ) - Please choose one
Creation of threads can be
static
dynamic
easy
difficult
Question No: 5 ( Marks: 1 ) - Please choose one
How many prevalent calling conventions do exist
1
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2
3
4
Question No: 6 ( Marks: 1 ) - Please choose one
VESA VBE 2.0 is a standard for
High resolution Mode
Low resolution Mode
Medium resolution Mode
Very High resolution Mode
Question No: 7 ( Marks: 1 ) - Please choose one
The serial port connection is a ------------------ connector
9pin DB 9
8pin DB 9
3pin DB 9
9pin DB 5
Question No: 8 ( Marks: 1 ) - Please choose one
Which of the following gives the more logical view of the storage medium
BIOS
DOS
Both
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None
Question No: 9 ( Marks: 1 ) - Please choose one
In STOSB instruction, when DF is clear, SI is
Incremented by 1
Incremented by 2
Decremented by 1
Decremented by 2
Question No: 10 ( Marks: 1 ) - Please choose one
After the execution of STOSW the CX will be
Decremented by 1
Decremented by 2
Incremented by 1
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Incremented by 2
Question No: 11 ( Marks: 1 ) - Please choose one
IRQ is referred to
Eight input signals
One output signal
One input signals
Eight output signals
Question No: 12 ( Marks: 1 ) - Please choose one
Which of the following IRQs is derived by a key board?
IRQ 0
IRQ 1
IRQ 2
IRQ 3
Question No: 13 ( Marks: 1 ) - Please choose one
eagle_eye
fantasy.fear@gmail.com
Which of the following IRQs is connected to serial port COM 1?
IRQ 4
IRQ 5
IRQ 6
IRQ 7
Question No: 14 ( Marks: 1 ) - Please choose one
The physical address of IDT( Interrupt Descriptor Table) is stored in _______
GDTR
IDTR
IVT
IDTT
Question No: 15 ( Marks: 1 ) - Please choose one
Assembly language is:
Low-level programming language
High-level programming language
Also known as machine language
Not considered closer to the computer
Question No: 16 ( Marks: 1 ) - Please choose one
The number of bits required to access 1MB of memory are
16 bits
32 bits
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Depends on the processor architecture
20 bits
Question No: 17 ( Marks: 1 ) - Please choose one
In STOSB instruction, SI is decremented or incremented by
3
2
1
4
Question No: 18 ( Marks: 1 ) - Please choose one
In programmable interrupt controller, which of the following ports is referred as a control port.
19
20
21
22
Question No: 19 ( Marks: 1 ) - Please choose one
INT 21 service 01H is used to read character from standard input with echo. It returns the result
in ______ register.
AL
BL
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CL
BH
Question No: 20 ( Marks: 1 ) - Please choose one
In device attribute word, which of the following bit decides whether it is a character device or a
block device
Bit 12
Bit 13
Bit 14
Bit 15
Question No: 21 ( Marks: 1 ) - Please choose one
In 9pin DB 9, which pin number is assigned to CTS (Clear To Send) ?
6
7
8
9
Question No: 22 ( Marks: 1 ) - Please choose one
In 9pin DB 9, which pin number is assigned to RD (Received Data) ?
1
2
3
4
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Question No: 23 ( Marks: 1 ) - Please choose one
VESA(Video Electronics Standards Association) organizes 16 color bits for every pixel in
5:5:5 format
5:6:5 format
6:5:6 format
5:6:7 format
Question No: 24 ( Marks: 1 ) - Please choose one
Motorola 68K processors have ....................... 23bit general purpose registers.
4
8
16
32
Question No: 25 ( Marks: 1 ) - Please choose one
Programmable Interrupt Controller (PIC) has
One input signals and eight output signals
One input signal and one output signal
Eight input signals and one output signals
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Eight input signals and eight output signals
Question No: 26 ( Marks: 1 ) - Please choose one
Video services are classified into...................... broad categories.
5
4
3
2
Question No: 27 ( Marks: 2 )
What are device drivers? give your answer in two to three lines.
Device drivers are operating system extensions that become part of the
operating system and extend its services to new devices. Device drivers in
DOS are very simple. They just have their services exposed through the file
system interface.
Device driver file starts with a header containing a link to the next driver in
the first four bytes followed by a device attribute word. The most important
bit in the device attribute word is bit 15 which dictates if it is a character
device or a block device. If the bit is zero the device is a character device and
otherwise a block device. Next word in the header is the offset of a strategy
routine, and then is the offset of the interrupt routine and then in one byte,
the number of units supported is stored. This information is padded with
seven zeroes.
Strategy routine is called whenever the device is needed and it is passed a
request header. Request header stores the unit requested, the command
code, space for return value and buffer pointers etc. Important command
codes include 0 to initialize, 1 to check media, 2 to build a BIOS parameter
block, 4 and 8 for read and write respectively. For every command the first
13 bytes of request header are same.
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Question No: 28 ( Marks: 2 )
For what purpose "INT 1" is reserved ?
INT 1 vector occupies location 4,
5, 6, and 7 INT 1, Trap, Single step Interrupt
This interrupt is used in debugging with the trap flag. If the trap flag is
set the Single Step Interrupt is generated after every instruction. By
hooking this interrupt a debugger can get control after every
instruction and display the registers etc. 8088 was the first processor
that has this ability to support debugging.
Question No: 29 ( Marks: 2 )
How interrupts are handled in protected mode.
Switching processor in the newer 32bit mode is a very easy
task. Just turn on the least significant bit of a new register called CR0
(Control Register 0) and the processor switches into 32bit mode called
protected mode. However manipulations in the protected mode are very
different from those in the read mode. Handling interrupts in protected mode is also different.
Instead of the IVT
at physical address 0 there is the IDT (interrupt descriptor table) located at
physical address stored in IDTR, a special purpose register. The IDTR is also
a 48bit register similar in structure to the GDTR and loaded with another
special instruction LGDT.
Question No: 30 ( Marks: 2 )
Which bit of acknowledge is used to generate IRQ7
Pin 10,
the ACK pin, is normally used by the printer to acknowledge the receipt of
data and show the willingness to receive more data. Signaling this pin
generates IRQ 7 if enabled in the PIC and in the parallel port controller. Pin
18-25 are ground and must be connected to the external circuit ground to
provide the common reference point otherwise they won’t understand each
other voltage levels.
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Question No: 31 ( Marks: 3 )
Write the name three flags which are not used for mathematical operations.
The three flags not used
for mathematical operations are the direction flag, the interrupt flag and the
trap flag.
Question No: 32 ( Marks: 3 )
"INT 13 - DISK - GET DRIVE PARAMETERS " uses which registers to return error flag and
error number.
INT 13 - DISK - GET DRIVE PARAMETERS
AH = 08h
DL = drive (bit 7 set for hard disk)
Return:
CF = error flag
AH = error code
Question No: 33 ( Marks: 3 )
Who is responsible for removing the parameter from the stack when we call a function in C and
Pascal?
In C the caller removes the parameter while in Pascal the callee removes
them. The C scheme has reasons pertaining to its provision for variable
number of arguments.
Question No: 34 ( Marks: 5 )
Read the passage carefully and choose proper word for each blank space from the list given
below .
In descriptors the 32bit base is scattered into different places because of compatibility reasons.
The limit is stored in 20 bits but the ...............defines that the limit is in terms of bytes of 4K
pages therefore a maximum of 4GB size is possible. The ................. must be set to signal that
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this segment is present in memory. DPL is the descriptor privilege level again related to the
protection levels in 386. .................. defines that this segment is to execute code is 16bit mode or
32bit mode. .................. is conforming bit that we will not be using. ..................signals that the
segment is readable. A bit is automatically set whenever the
segment is accessed.
(A bit, C bit, G bit, D bit, P bit , R bit, B bit)
Question No: 35 ( Marks: 5 )
Write assembly language instructions to set the timer interrupt frequency at 1 ms.
Question No: 36 ( Marks: 5 )
In the context of " INT 13 - DISK - WRITE DISK SECTOR(S)" fill the blanks by choosing the
correct answer against each blank space from the list given at the bottom.
AH = ....................
AL = ...............................
CH = ..............................
CL = sector number 1-63 (bits 0-5)
high two bits of cylinder (bits 6-7, hard disk only)
DH = .....................................
DL = drive number (bit 7 set for hard disk)
ES:BX -> .......................................

By : ADEEL ABBAS 

www.allvupastpapers.blogspot.com 

AdeelAbbasbk@gmail.com