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COMPUTER HARDWARE & NETWORKS

Q.CODE: 184

PART-A

(Each question carries 2 marks, Answer any FIVE questions, Q.No. 8 – Compulsory)

1. Write short notes on 1TB RAM.

1 TB RAM is a new type of RAM that can store 1TB data (tera byte) in a chip smaller

than stamp. This was developed by California tech using a technology named crossbar.

2. Write short notes on USB port.

USB port refers to Universal Serial Bus port. Using this port, we can connect all types of

I/O devices such as mouse, keyboard, scanners, digital camera, modem etc.

3. What do you mean by beep codes?

POST error codes are audio codes consisting of various beeps that identify the faulty

component. If any problem is detected during start of the system, the different series of

audio codes are sounded.

4. Write short notes on LCD, the mobile phone component.

LCD is used to display the input given by the user, menus, setting, contacts etc stored in

the mobile phone.

5. List the types of networks.(any two)

i) LAN(Local area network)

ii) MAN(Metropolition area network)

iii) WAN(Wide area Network)

iv) CAN (Controller area Network)

iv) HAN(Home area network)

v) Internet

vi) Intranet

vii) Extranet

6. What do you mean by gateway?

A gateway is defined as an internet working system. This is used to joint two networks

that use different base protocol for communication.

7. What do you mean by TC and UDP?

TCP: To transmit data between computers a physical connection must be established

between both ends.

UDP: To transmit data between computers a no physical connection between the

computers (or wireless communication)

8. Write short notes on IPV6.

IP stands for Internet protocol and V6 indicates version 6.

This protocol routes data packets between networks.

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PART-B

(Each question carries 3 marks, Answer any FIVE questions, Q.No. 16 – Compulsory)

9. Write short notes on serial ATA.

Serial ATA is a serial interface for connecting hard disk drives with the system.

The important features are (any three)

i) It requires low signal voltage of 500mv peak to peak.

ii) It can have flexible connector cable up to 1 meter.

iii) The number of pins in the connector is reduced below 40 .

iv) Its data transfer rate is 150MB/s to 600MB/s.

v) Data transmission is guaranteed.

10. Write short notes on Bluetooth interface.

Bluetooth is a wireless device. Using this, data can be exchanged within a short distance from

fixed and mobile devices. This uses open wireless protocol. Bluetooth uses a video technology called

frequency hopping spread spectrum for communication.

11. Write short notes on earpiece.

Ear-piece is used to convert electrical signal to sound signal.

Ear-piece is the one of the component of mobile phone.

It is used to hear the sound of the mobile phone.

12. What are the uses of secret codes in mobile phones? (any three)

code Uses

*#*#0*#*# LCD display test

*#*#1234#*#* PDA and phone firmware

info

*#*#1111#*#* FTA software version

*#06# Displays IMEI number

*#*#2222#*#* FTA hardware version

13. Explain mesh topology.

As shown in the figure each device is connected with all other devices in the topology.

The devices are uniquely identified by means of a network address.

If a device wants to send a data to another, it can send directly to the destination device.

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14. What do you mean by routers?

A router is a device containing software and hardware.

This is used to forward data packets from one network to another network.

The figure shows the structure of networks connected by router.

15. Write short notes on OSI model.

The full form of OSI is Open System Interconnection.

OSI model has seven well defined layers to do communication among computers.

The layers are (or) Diagram

i. Physical layer

ii. Data link layer

iii. Network layer

iv. Transport layer

v. Session layer

vi. Presentation layer

vii. Application layer

16. Write short notes on POP.

The full form of POP is post office protocol.

The client software is installed in the client and the server software is installed in the

server.

POP has two modes. They are

i. Delete mode

ii. Keep mode

PART-C

(Each question carries 10marks, Answer division (a) or division (b))

17. (a) Explain the parts of mother board.

Mother board

The mother board consists the following (3 marks)

i. Systems microprocessor CPU to carry out the calculation and processing.

ii. Base memory or main memory to store both instruction and data.

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iii. Support circuitry like bus decode logic, boot ROM and POST.

iv. Expansion slots to insert add-on-cards, controllers and interfaces for peripheral devices.

v. Some motherboard contains drive interface logic, printer interface logic and serial interface

logic.

Processor sockets/slots (2 marks)

A processor or CPU sockets /slot is a connection point. This is used to connect the processor to

the mother board. There are two types of sockets. They are

i. Pin grid array(PGA)

ii. Land grid array(LGA)

Pin grid array (PGA) contains pins on the processor and holes in the sockets to hold the processor tightly.

Land grid array (LGA) (Diagram-2marks)

Contains contact or lands on the processor and pins on the socket.

Expansion slot (3 marks)

Expansion slots on the mother board are used to add additional features such as video, sound,

memory, graphics etc. the different expansion slots are

i. I/O expansion slots

I/O expansion slots are used to add I/O devices like FDD, HDD, printers, mouse etc.

The following are the examples of expansion slot

IDE slot

SATA slot

SCSI slot

VESA slot

PCI slot

ii. Memory expansion slots

Memory expansion slots are used to insert main memory(RAM) into the computer. There

are two to four memory slots. They are i) SIMM slot ii)DIMM slot iii)RIMM slot

[OR]

17. (b) Explain the reading and writing operations in DVD/RW.

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(Diagram-4marks)

DVD/RW

Rewritable DVD is a device that can be used to erasing and writing again and again.

The fig is shows the cross sectional view of a single sided 4 layer DVD.

Writing: (2 marks)

During writing, Laser beam of wave length 650µm is used to heat select spots above 500º-700ºc.

So the spots changes to liquid state. Then the spots are allowed to cool. After cooling the spots

becomes amorphous state.

Reading: (2 marks)

To read data in the DVD, a low power laser is made to fall on the surface of the DVD. The

amorphous area reflects less light and crystalline area reflects more light. With the help of the

difference in reflectivity we can read the data.

Erasing: (2 marks)

To erase the data on the DVD, a medium power laser of temperature 200ºC is made to fall on the

recording layer. This melts the amorphous area and reverts back to crystalline state.

18. a) Explain the operation of dot matrix printer with suitable diagram.

Operation: (6 marks)

In this printer the characters are formed with the help of the dots. So this is called dot matrix printers.

There are three types of dot matrix printers. They are

(a) 7 pin printers

(b) 9-pin printers

(c) 24 pin printers

The print head of the dot matrix printer consists of small needles. Each needle can move freely.

Each needle can be made to print a dot by means of a hammer action that forces the needle to come

out and press the ribbon against the paper. Standard characters are produced in a dot matrix.

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(Diagram-4marks)

The characters are printed column by column and not all at once. For example to print the

character ‘T’ initially pin no 1 is made to contact the ribbon. Thus first column of the characters is

got. Then the print head is moved towards right and once again the pin 1 made to contact the ribbon.

Thus the second column of the character is got. Then the print head is moved to get the third column

and so on .

[OR]

18) . (b) Explain the working principle of LCD display.

Liquid Crystal Displays (LCD):

LCD Principles: (2 marks)

Most liquid crystals contain a long rod –like molecules. In their natural state the molecules are

arranged almost parallel to their long axis. By placing the liquid crystal in a finely grooved surface,

the molecules arrangement can be controlled. That is if the grooves are parallel, the alignments of the

molecules also become exactly parallel.

There are two principles behind LCD. They are (i) first principle (2 marks)

(Diagram 2 marks)

Polarising filter: a light is made to fall on the polarizing filter. The polarizing filter changes the

direction of the light parallel to the axis of the filter.

Grooved Plate1 and Plate2: Liquid crystals are placed in the finely grooved plates 1 and 2. These

plates are kept perpendicular to each other.

Polarising filter: This polarizer is kept perpendicular to the top filter.

ii) Second principle. (2 marks)

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(Diagram 2 marks)

If electrical voltage is given across the liquid, the molecules between the grooved plates realign

vertically. Because of this, the polarized light is passed through without any twist. So the bottom

polarizer does not allow the light to pass producing a dark pixel.

By changing the voltage across the liquid crystal, we can make the images to appear on the

screen.

19. (a) Explain the power management and advanced chipset features in BIOS.

POWER MANAGEMENT: (any 5) [5 marks]

The CMOS setup has number of power management features to save the energy when the system

is idle.

The following are the power management options in CMOS.

i. Doze timer: this option is used to set the time delay before the system reduces its 80%

activity.

ii. Green timer of Main board: This option is used to set the time before a CPU of an idle

system will shutdown.

iii. HDD standby timer: this option used to set the shutdown time of HDD after the system

is idle.

iv. Modem use IRQ: this option is used to enter the IRQ assigned to modems.

v. Power management scheme: this option is used to defined the amount of power

management in the system by the user.

vi. Standby timer: this option is used to set the time delay before the system reduces its

92% of its activity.

vii. Suspend switch: this option is used to enable or disable hardware suspend switch on the

mother board.

viii. Suspend timer: this option is used to set the time after which the system goes into the

most inactive state.

ix. Video off option: this option is used tom turn off the display.

ADVANCED CHIPSET FEATURES: (any 5) [5 marks]

The advanced chipset features in CMOS allows the users to tune the performance of the chipset.

i. 16 -bit memory, I/O wait state: this entry lists the number of wait states inserted with

16-bit memory and input output operations.

ii. 8-bit memory, I/O wait state: this entry lists the number of wait states inserted with 8-

bit memory and input output operations.

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iii. Alternate bit in tag RAM: Tag bits are used to determine the state of the information

stored in the L2 cache.

iv. Automatic Configuration: When this option is enabled, BIOS automatically set the

settings in the advanced chipset setup.

v. Burst copy back option: This option can be enabled or disabled. When enabled it

makes the chipset to make a second memory read

vi. Burst refresh: This option performs several refresh cycles at once.

vii. Burst RAM cycle: This option is used to specify the timing of the burst mode read and

write cycles from the L2 cache.

viii. Bus mode: This option is used to select the clock mode used to drive the bus.

[OR]

19. (b). How will you assemble and disassemble the different types of mobile phones.

Assembling of different types of mobile phones:[5 marks]

The steps given below are used to assemble a mobile phone:

i. Fix the vibrator strips, speaker and volume button.

ii. Fix the mother board

iii. Connect the antenna with wire

iv. Place the camera and connect it

v. Place the buzzer

vi. Put the camera cover

vii. Make sure that the LCD is working before you place the screen

viii. Put battery and battery cover

Disassembling of different types of mobile phone [5marks]

The steps given below are used to disassemble a mobile phone:

i. Switch off the phone

ii. Remove the battery cover

iii. Remove the battery, SIM card memory card(if any)

iv. Remove all the screws from the phone

v. Lift back the cover with the help of flat screw driver

vi. Remove the strips(buzzer strip, display, camera, volume and speaker button strips)

vii. Remove the antenna wire from the out side

viii. Remove the motherboard and vibrator.

20. (a) Explain WAN-LAN-HAN with neat diagram

WAN (WIDE AREA NETWORK) (1 mark)

A network connection implemented within a large geographical distance between countries or

continents is called WAN.

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(Diagram 2 marks)

Uses:

1. It covers large distance

2. It can be used by all types of users.

3. The cost of data communication is low.

LAN (LOCAL AREA NETWORK) (1mark)

A network connection implemented within a building or in an office is called LAN. The

commonly used topologies are bus, star and ring.

(Diagram 2 marks)

Uses:

1. It allows sharing the resources such as hardware or software.

2. The cost of data communication is low.

3. Network management is easy.

HAN (HOME AREA NETWORK) (2 marks)

Home area network is a local area network used within the home. It is used for communication

between the digital devices in the home. The following devices normally connected in home network.

a) Two or more computers

b) Printers, faxes, scanners

c) Internet connection

d) Television

e) Video games

f) Home security systems etc.

The connections between devices are done by means of cables or by wireless.

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(Diagram 2 marks)

Uses:

1. Home appliances such as micro oven, AC, lighting etc. can be controlled automatically.

2. Using HAN home appliances such as security systems, lights AC etc can be remotely controlled.

3. Computer resources such as printer, scanner etc can be shared.

[OR]

20. (b) Explain the layered architecture of OSI model.

Layered Architecture and functions:

(Diagram 4 marks)

OSI model has seven well defines layers to do communication among computers.

The functions of different layers are (Explanation 6 marks)

1) PHYSICAL LAYER:

This is lowest layer in the OSI model. The main functions are

a) It is responsible for establishing a physical connection between sender and

receiver.

b) It is responsible for sending and receiving raw bits of data between sender and

receiver through communication channel.

2) DATA LINK LAYER:

This layer is responsible for the transfer of data over the channel. The main functions are

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a) It takes the raw bit of data from physical layer and transforms into error free data

frames and pass it to the network layer.

b) It process the acknowledgement frames sent by the receiver.

3) NETWORK LAYER:

This layer is responsible for controlling the operation of the subnet. The main duties are

a) To deliver the data packet from source or destination.

b) To find the shortest route from sender or receiver.

c) To control the congestion of packets in the network.

4) TRANSPORT LAYER:

This layer is used to provide reliable, cost effective data transport from source machine to

destination machine. The important functions are

a) It accepts data from session layer and split it into smaller units and pass it to

network layer.

b) It also checks whether all the pieces of data are arrived at the destination.

5) SESSION LAYER:

This layer is used to establish a meeting between users of different machines. The

important functions of this layer are

a) It allows the user to log into a remote time sharing system.

b) It allows to transfer file between systems.

c) It allows communication between two systems.

6) PRESENTATION LAYER:

The important functions of this layer is to provide a general syntax and meaning of the

information exchanged between systems.

7) APPLICATION LAYER:

This layer contains number of services that are commonly needed by the users. The

important functions are mail services, file transfer and access, remote login and accessing

World Wide Web.

21. (a) Describe the connection oriented and connectionless service in TCP/IP

Connection oriented service: [5 Marks]

In connection oriented service, a physical connection must be established the sender and the

receiver. The following steps

1. Sender requests the receiver for establishing a connection.

2. Receiver accepts the request.

3. Connection established.

4. Data transfer takes place between sender and receiver.

5. Connection termination after sending all data. TCP is a Connection oriented protocol.

Connection Less service [5 Marks]

1. The packets are sent from one computer to another ( no

need for connection establishment ,connection release & no fixed path)

2. The packets are not numbered. It uses packet switching for transmission of data

3. May be delayed, lost or arrive out of sequence

4. There is no acknowledgment.

5. UDP is a connectionless protocol.

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[OR]

21. (b) Explain FTP, Telnet, SMTP and HTTP.

FTP (FILE TRANSFER PROTOCOL) (2 marks)

This is a standard used to copy files from one host to another through internet.

This uses the services of TCP. During file transfer FTP establishes two connections between the

client and the server. They are

1. One connection is established through port 20 to transfer data.

2. Another connection is established through port 21 to send control information.

FEATURES:

1. FTP can transfer ASCII, EBCDIC and image files.

2. FTP can transfer files in a streams or blocks or compressed mode.

3. User can interact with FTP.

4. It allows to get the list of files in the remoter computers.

5. It allows user authentication.

TELNET: (2 marks)

Telnet is a protocol used to provide a bidirectional interactive text oriented

communication between computers connected in the network.

Using telnet, the user can access any computer remotely. The remote computer is called

host. Once telnet establishes a connection to the host, the telnet client becomes a virtual terminal.

FEATURES:

1. Al l telnet client and host uses TCP/IP as the underlying communication

protocol.

2. Port 23 is reserved for client and server communication.

3. All telnets clients and servers transmit predefined set of ASCII codes.

SMTP (SIMPLE MAIL TRANSFER PROTOCOL): (2 marks)

This gives standards for e-mail communication through internet. To communicate

through e-mail an addressing system is needed.

The general form is

localpart@domain name

The operation of SMTP starts from the sender of the mail. If a user wants to send a mail,

the SMTP pushes the mail to the receiver’s mail box even if the receiver does not want it. If the

receiver wants to read the mail, it uses a pull protocol namely POP or IMAP to access the mail.

SMTP can send messages only in 7 bit ASCII format. The services offer to the users are

composing messages, reading messages, replying messages, forwarding messages and handling

mail boxes.

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(Diagram-

2marks)

HTTP (HYPER TEXT TRANSFER PROTOCOL) (2 marks)

This is used to access data from the World Wide Web. The client and server interaction

can be viewed.

1. Client request the server using http.

2. Server responds the client through http and closes the connection.

The general form

Method URL HTTP version

The different methods are

GET - request to get a web page

HEAD - request to read the header of a web page

PUT -request to store a web page

POST -request to store and update a web page.

DELETE -request to remove a web page

LINK - request to connect two resources.

UNLINK - request to disconnect two resources.

SERVER RESPONSE:

1. HTTP version

2. Status code

3. Status phrase

Prepared by

GOMATHY L [35035203] Lecturer

503, S A Polytechnic College,

Chennai – 600 077