MCA111 – Fundamentals of Computer and IT Assignment Subject MCA111

Assignment Set -1

1. Question. Explain the features of a mouse and a track ball

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, images or diagrams etc.

Track ball: -   is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a pointer.

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.

2. Question. What is data communication? Explain different Data Transmission methods.

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 thechassis 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.

3.  Question. What is an IP address? Describe the classes of IP

addresses.

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.

Assignment Set -2

1.   Question. Write short notes on any five Input devices.

Answer:

You may also like:-What are computer output devices? Explain its different types with examples.

Inputs devices are those devices which take input from users in the simple form and convert the data/information into digital form i.e. 1 or 0.

Input device categorisation:-

1) Online input devices/Direct line entry devices:-On line input devices are those devices which are directly connected to computer example keyboard, mouse etc.

2) Offline input devices/Source entry devices:-Offline input devices are those devices which are not directly connected to computer example scanning device.

Types of common input devices:-

1)Keyboard:-Keyboard is a well known input device which contains alphabets, numeric/digits, special keys, function keys etc.Keyboard can be of serial or parallel.

Alphabets:-A to Z,a to z.

Numeric key:-0 to 9

Special keys:-shift, spacebar, ctr, alt etc.

Functions key:-F1, F2.....F12.

Keyboard is used to convert these above mention keys into digital form of computer.

2) Mouse:-Mouse is an input device which is also called a pointing device. It is used to move the cursor on the screen. Mouse works in GUI(Graphical User Interface) mode. Mouse is of different-2 types in which some are physical mouse, optical mouse, and cordless mouse.

3) Joystick:-It is also called as game controller device. Joystick is a remote control device which is used in gaming purpose. We will also play game with keyboard but joystick gives more simplicity and more speed than keyboard.

4) Scanner:-Scanner is a example of input device which are mainly used to check OMR sheets. It is also used to copy text, images in the form of soft copy.

5)Bar Code Reader(BCR):-Bar Code Reader is generally used in shopping malls,BCR read the bar code and display the rate of item on the computer screen. It is also used to recognise courier products.BCR takes input in the form of code and convert this bar code into computer language (0 or 1).

Some other input devices are Light pen, track ball, MICR, web camera, touch screen, microphones etc.

2.   Question. Differentiate combinational circuit and Sequential circuits.

Answer:

Ans: Combinational Circuits

A combinatorial circuit is a system containing basic Boolean operations (AND, OR, NOT), some inputs, and a set of outputs. Since each output corresponds to an individual logic function, a combinatorial circuit often implements several different Boolean functions. It is very important that we remember this fact – each output represents a different Boolean function.

A computer’s CPU is built up from various combinatorial circuits. For example, you can implement an addition circuit using Boolean functions. Suppose you have two one-bit numbers, A and B. You can produce the one bit sum and the one-bit carry of this addition using the two

Boolean functions:

S = AB’ + A’B Sum of A and B.

C = AB Carry from addition of A and B.

These two Boolean functions implement a half-adder. Electrical engineers call it a half adder because it adds two bits together but cannot add in a carry from a previous operation.

A full adder adds three one-bit inputs (two bits plus a carry from a previous edition) and

Produces two outputs: the sum and the carry. The two logic equations for a full adder are

S = A’B’Cin + A’BCin’ + AB’Cin’ + ABCin

Cout = AB + ACin + BCin

Although these logic equations only produce a single bit result (ignoring the carry), it is easy to construct an n-bit sum by combining adder circuits. So, as this example clearly illustrates, we can use logic functions to implement arithmetic and Boolean operations.

Sequential Circuits

A digital logic circuit or system is usually made up of combinational elements such as NAND and NOR gates and memory elements which may, for example, be discrete flip-flops or latches.

Alternatively, an interconnection of these devices may be found in a shift register, a counter, or in a variety of MSI and LSI packages.

In effect, logic operations can be performed sequentially, information being stored in a memory element and released at some specified instant later so that it can take part in a controlled combinational operation.

Systems operating in this way are called sequentially operated systems. There has always been considerable confusion over the use of the terms latch and flipflop. It will be assumed in this book that a flip-flop is a device which changes its state at times when a change is taking place in the clock signal.

3.   Question. What is computer memory? Explain its types.

Answer:

Ans: In computer, memory denotes to the state information of a computing system, as it is kept active in some physical structure. Computer, memory means to the state information of a computing system, as it is kept active in some physical structure. The term "memory" is used for the information in physical systems which are fast (i.e. RAM), as a distinction from physical systems which are slow to access (i.e. data storage). By design, the term "memory" denotes to temporary state devices, whereas the term "storage" is reserved for permanent data. Advances in storage technology have blurred the distinction a bit memory kept on what is conventionally a storage system is called "virtual memory".

There are two types of computer memory: primary and secondary.

Primary memory is accessible directly by the processing unit. RAM is a model of primary memory. As soon as the computer is switched off the contents of the primary memory is lost. We can store and retrieve data much quicker with primary memory compared to secondary memory.

Primary memory is computer memory that a processor or computer accesses first or directly. It allows a processor to access running execution applications and services that are temporarily stored in a specific memory location.

Secondary memory such as floppy disks, magnetic disk, etc., is located outside the computer. Primary memory is more expensive than secondary memory. Because of this the size of primary memory is less than that of secondary memory. Computer memory is used to store two things: i) instructions to execute a program and ii) data. When the computer is doing any job, the data that have to be processed are stored in the primary memory. This data may come from an input device like keyboard or from a secondary storage device like a floppy disk.

Secondary memory is computer memory that is non-volatile and persistent in nature and is not directly accessed by a computer/processor. It allows a user to store data that may be instantly and easily retrieved, transported and used by applications and services. Secondary memory is also known as secondary storage.