Assignment of Fundament of Computer IT
Question 1:- Define CPU. What
are the three sub units of CPU? Explain each?
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Answer:-
CPU (Central Processing
Unit):- The
CPU is attached to the Main Memory and this combination is the basis of the
modern general purpose computer. The CPU has two main task
i) To control the fetching and interpretation of
instructions from memory and the movement of data between memory and the CPU.
ii) To carry out (execute) the instructions
1.The Control Unit controls:- the fetching of
instructions from main memory, the interpretation and the execution of
these instructions and the passing of
data to and from the Arithmetic/Logical Unit for computation.
2.The Arithmetic/Logical Unit (ALU):- carries out arithmetic operations on
integer (whole number) and floating point (with a decimal point) operands. It
also performs simple logical operations on Logical ( True of false ) operands
and can make comparisons between numeric operands.
3.Registers:-The registers are small units of memory
that the control Unit and the ALU use for the storage of intermediate results
and control information. The numbers and size of the registers depends upon the
particular computer. Typically there will be sixteen or thirty two General
Purpose Registers. It is important to note that since the registers are
internal to the CPU they can be accessed at high speed by the CPU.
Question 2. Differentiate between integrated
Circuits and microprocessors?
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Answer:-
Integrated Circuits:- An
integrated circuit is Transistors were miniaturized and placed on silicon
chips, called semiconductors, which drastically increased the speed and
efficiency of computers and it have containing multiple transistors, diodes
etc. fabricated on a single semiconductor die, usually silicon. A chip is a
small piece of semi conducting material (usually silicon) on which an
integrated circuit is embedded. A typical chip is less than ¼-square inches and
can contain millions of electronic components (transistors).Computers consist
of many chips placed on electronic boards called printed circuit boards. There
are different types of chips. For example, CPU chips (also called
microprocessors) contain an entire processing unit, whereas memory chips
contain blank memory. Computer chips,
both for CPU and memory, are composed of semiconductor materials.
Semiconductors make it possible to miniaturize electronic components, such as
transistors. Not only does miniaturization mean that the components take up
less space, it also
means that they are faster and require less energy.
Integrated circuits
Microprocessors:- A
processor is short for CPU (central processing unit) in a computer, responsible
for doing calculations,
organizing program flow etc. - most everything apart
from data storage and input/output.
In modern computers there are one or more CPUs which
are almost invariably implemented in one
integrated circuit (Intel Pentium etc.). In the past
that was not the case - the processor was made of
several integrated circuits, or discrete components,
or even mechanical gears.
Three basic characteristics differentiate
microprocessors:
Instruction Set: The set of instructions that the
microprocessor can execute.
Bandwidth: The number of bits processed in a single
instruction.
Clock Speed: Given in megahertz (MHz), the clock
speed determines how many instructions per
second the processor can execute.
Microprocessor
Question 3.What is the significance of Processor mode? Explain three
types of processor modes?
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Answer:-
Processor Modes:-
Processor modes refer to the various
ways that the processor creates an operating environment for itself.
Specifically, the processor mode controls how the processor sees and manages
the system memory and the tasks that use it. There are three different modes of
operation, that resulted from the evolution of the PC from its humble
beginnings with the Intel 8088 chip.
1.Real Mode:
The original IBM PC could only
address 1 MB of system memory, and the original versions of DOS created to work
on it were designed with this in mind. DOS is by its nature a single-tasking
operating system, meaning it can only handle one program running at a time. The
decisions made in these early days have carried forward until now, and in each
new processor, care had to be taken to be able to put the processor in a mode
that would be compatible with the original Intel 8088 chip. This is called real
mode.
When a processor is running in real
mode, it acts like an "8088 on steroids". What this means is that it
has the advantage of speed, but it otherwise accesses memory with the same
restrictions of the original 8088: a limit of 1 MB of addressable RAM, and slow
memory access that doesn't take advantage of the full 32-bit processing of
modern CPUs. All processors have this real mode available, and in fact the
computer normally starts up in real mode.
2.Protected Mode:
Starting with the 80286 chip in the
IBM AT, a new processor mode was introduced called protected mode. This
is a much more powerful mode of operation than real mode, and is used in all
modern multitasking operating systems. The advantages of protected mode
(compared to real mode) are:
- Full access to all of the system's memory. There is no
1 MB limit in protected mode.
- Ability to multitask, meaning having the operating
system manage the execution of multiple programs simultaneously.
- Support for virtual memory, which
allows the system to use the hard disk to emulate additional system memory
when needed.
- Faster (32-bit) access to memory, and faster 32-bit
drivers to do I/O transfers.
The name of this mode comes from its
primary use, which is by multitasking operating systems. Each program that is
running has its own assigned memory locations, which are protected from
conflict with other programs. If a program tries to use a memory address that
it isn't allowed to, a "protection fault" is generated. If you've
ever used Windows 3.x, you know exactly what I am talking about. :^)
3.Virtual Real Mode:
The third mode of processor
operation is actually an additional capability, an enhancement, of protected
mode. Protected mode is normally used to run graphical multitasking operating
systems such as the various flavors of Windows. There is often a desire to be
able to run DOS programs under Windows, but DOS programs need to be run in real
mode, not protected mode.
Virtual real mode was created to
solve this problem. In essence, it emulates real mode from within protected
mode, allowing DOS programs to run. A protected mode operating system such as
Windows can in fact create multiple virtual real mode machines, each of
which appear to the software running them as if they are the only software
running on the machine. Each virtual machine gets its own 1 MB address space,
an image of the real hardware BIOS routines, everything.
Question 4. Explain the features of
a mouse and a track ball?
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Answer:-
Mouse:-This Input device
is categorized as a pointing device because it is used to
point and select an
option on the monitor. It is small boxlike object that is connected to the
computer by a cable and can be rolled around on the table.
A pointer on the screen follows the
movements of the mouse; rolling the
mouse left moves the pointer left by
an equipment amount, rolling the
mouse in the right direction moves
the pointer in the right direction, rolling
the mouse in the up direction moves
the pointer in the up direction, rolling
the mouse in the down direction
moves the pointer in the down direction and
you can roll the mouse in a angular
direction also. In order to select an
option on the computer screen, the
user should move the pointer at the
desired position and press the
button on the mouse. The mouse can be
used to open menus, select texts
for editing, move objects on the screen,
draw images or diagrams
etc.
Mouse
Compared with a mouse, a trackball has no limits on effective travel; at times, a mouse can reach an edge of its working area while the operator still wishes to move the screen pointer farther. With a trackball, the operator just continues rolling, whereas a mouse would have to be lifted and re-positioned. Some trackballs, such as Logitech's optical-pickoff types, have notably low friction, as well as being dense (glass), so they can be spun to make them coast. The trackball's buttons may be situated to that of a mouse or to a unique style that suits the user.
Large trackballs are common on CAD workstations for easy precision. Before the advent of the touchpad, small trackballs were common on portable computers, where there may be no desk space on which to run a mouse. Some small thumb balls clip onto the side of the keyboard and have integral buttons with the same function as mouse buttons.
Track Ball
Question 5. What is data
communication? Explain different Data Transmission methods?
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Answer:-
Data
Communication:-
Data communication
is the transfer of data or information between a source
and a receiver,
the source transmits the data and the receiver receives it.
The distance over
which data moves within a computer may vary from a few thousandths of an inch,
as is the case within a single IC chip, to as much as several feet along the
backplane of the main circuit board. Over such small
distances, digital
data may be transmitted as direct, two-level electrical
signals over
simple copper conductors. Except for the fastest computers,
circuit designers
are not very concerned about the shape of the conductor or the analog
characteristics of signal transmission. Data Communications concerns the
transmission of digital messages to
devices external
to the message source. "External" devices are generally
thought of as
being independently powered circuitry that exists beyond the
chassis of a computer or
other digital message
Data
Transmission methods:-
There are three methods of data
transfer. These methods are discussed
below:
1. Simplex
communication:
In
this type, data transfer occurs in only one
direction, i.e., either from source
to destination or destination to source
machines.
2. Half-duplex
communication:
In
this type, data transfer occurs in either
directions, but not simultaneously.
3.Full-duplex
communication: In this type, data transfer occurs in
either
direction simultaneously. The
protocol must also determine the number
of logical channels per connection
along with their individual priorities.
Many networks provide at least two
logical connections per channel, one
for normal data, and one
for urgent data.
Question 6. What is an IP address?
Describe the classes of IP addresses?
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Answer:-
IP Address:- IP addresses are represented by a 32-bit
unsigned binary value. It is usually
expressed in a dotted decimal
format. For example, 9.167.5.8 is a valid IP
address. The numeric form is used
by IP software. The mapping between
the IP address and an
easier-to-read symbolic name, for example,
myhost.ibm.com, is done by the Domain
Name System (DNS).
To identify a host on the Internet,
each host is assigned an address, the IP
address, or in some
cases, the Internet address. When the host is attached
to more than one network, it is
called multihomed and has one IP address
for each network
interface. The IP address consists of a pair of numbers:
IP
address = <network number><host number>
The network number portion
of the IP address is administered by one of
three Regional Internet Registries
(RIR):
i)American
Registry for Internet Numbers (ARIN): This registry is
responsible for the administration
and registration of Internet Protocol
(IP) numbers for North America,
South America, the Caribbean, and
sub-Saharan Africa.
ii) Reseaux IP
Europeans (RIPE):
This
registry is responsible for the
administration and registration of
Internet Protocol (IP) numbers for
Europe, Middle East, and parts of
Africa.
iii) Asia Pacific
Network Information Centre (APNIC): This registry is
responsible for the administration
and registration of Internet Protocol
(IP) numbers within the
Asia Pacific region.
we explain the rules used to divide
an
IP address into its network and
host parts.
The binary format of the IP address
128.2.7.9 is:
10000000 00000010
00000111 00001001
Class-based IP addresses:-
Class
A addresses:
These
addresses use 7 bits for the <network> and 24
bits for the <host> portion
of the IP address. This allows for 27-2 (126)
networks each with 224-2 (16777214)
hosts – a total of more than 2 billion
addresses.
Class
B addresses:
These
addresses use 14 bits for the <network> and 16
bits for the <host> portion
of the IP address. This allows for 214-2 (16382)
networks each with 216-2 (65534)
hosts – a total of more than 1 billion
addresses.
Class
C addresses: These
addresses use 21 bits for the <network> and 8
bits for the <host> portion
of the IP address. That allows for 221-2 (2097150)
networks each with 28-2 (254) hosts
– a total of more than half a billion
addresses.
Class
D addresses: These
addresses are reserved for multicasting (a sort
of broadcasting, but in a limited
area, and only to hosts using the same
Class D address).
Class
E addresses: These
addresses are reserved for future or
experimental use.
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