Download Chapter 2: Computer Components

Chapter No. 2
Computer Components
2.01 Complete the following statements.
i)
A system unit of computer consists of a ______________ and _______________ .
ii) CPU stands for __________________________________.
iii) ALU stands for __________________________________.
iv) Internal memory unit that are the small temporary storage of a computer are called
________________.
v) A 16 bit bus can transfer _________________ bytes at a time.
Ans:
2.02
i) CPU, memory
ii) Central Processing Unit
iv) register
v) 2
Tick (
iii) Arithmetic and Logic Unit
) the following statements either true or false.
i)
ii)
iii)
iv)
The CPU of a computer is one of its input unit.
The CPU of a system process the data as instructed and sends the results to an output unit.
The control unit carries out logical computation.
Registers are the small storage the data that hold the instructions and data currently being
in process.
v) One of the important functions of RAM is to generate characters.
Ans:
i) False
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ii) True iii) False
iv) True v) False
Encircle one choice A, B, C, or D in each of the multiple choice questions.
i)
ii)
Which of the following are present in a system unit.
a. I,II & III
b. II & III
c. I, II & IV
d. I, II, III, IV
Where (I) Input Unit, (II) CPU, (III) Memory Unit, (IV) Output Unit
RAM of a computer is a
a. Permanent storage
c. Primary Storage
b. Secondary Storage
d. Backing Storage
iii) The brain of an electronic computer is its:
a. CPU
b. ALU
iv) An 8-bit address bus can address a memory of:
a. 1 Byte
b. 8 Byte
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c. CU
d. ROM
c. 256 bits
d. 256 Bytes
v)
Which of the following is not a semiconductor memory?
a. ROM
b. RAM
c. PROM
d. none
Ans:
i) b
ii) c
iii) a
iv) d
v) d
Q.5.04 Match the items given in Column I with those given in Column II
Column I
Column II
i)
Hardware
a)
Booting Process
ii)
Software
b)
LPT
iii)
Serial Port
c) Physical Components of a
computer system
iv)
Parallel Port
d) Procedure necessary to run the
computer
v)
ROM
e)
COM
Ans:
i) c
ii) d
iii) e
iv) b
v) a
Q.2.05 Differentiate between hardware and software of a computer.
Hardware
1. Computer hardware are the physical
components.
2. These are installed in a computer box as
well as the devices connected with it e.g.
mouse, keyboard, monitor etc.
3. These are touchable.
Software
1. Computer software is the set of
instructions.
2. These are installed in a Hard Disk e.g.
MS Windows, MS Word etc.
3. These are not touchable.
Q.2.06 Describe the main functions of CPU.
Following are the main functions of CPU:

It controls the entire computer system
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

It executes the instructions given to it.
The CPU processes data as instructed and sends the results to an output unit.
Q.2.07 Describe the working and function of ALU.
Working of ALU:
ALU contains a number of adder and logic gates in addition to various types of registers.
Registers such as address registers, accumulators, instruction registers, program counter
etc. help the computer to process the data. ALU performs all the processing in a CPU.
Function of ALU:
It also carries out arithmetic operations like addition, subtraction, division,
multiplication as well as logic operations like equal to, not equal to, less than, greater
than etc.
Q.2.08 Discuss the importance of main memory. Explain the types of main memory.
Importance of main memory:
Main memory of a computer is its internal memory also called the primary memory.
Generally the main memory is on semiconductor chips. These chips are connected with
the CPU on the motherboard. Main memory is very fast as it is directly accessible by the
CPU.
Types of main memory:
Following are two types of main memory:
i) RAM:
RAM is Random Access Memory. It is a temporary memory of a computer. It is also called
volatile memory because everything that is stored in RAM is lost when the computer is turned
off. RAM is a semiconductor memory with no moving part. Data can be accessed from RAM at
very high speed very close to the speed of light.
ii) ROM:
ROM is Read Only Memory. It is a permanent of computer. It provides instructions to CPU
during booting process. It is a non-volatile memory of a computer because the contents of this
type of memory are not lost when the computer is turned off. ROM is a semiconductor memory
generally programmed by the manufacture.
Q.2.09 Describe the function of control unit.
The CU is the most important part of the CPU. It control and coordinates the activities of
all the units of a computer system. It performs this function by issuing necessary
commands to respective units of the computer. The control unit fetches an instruction
from RAM and stores it in an instruction register and moves it to one of the ALU
registers.
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Q.2.10 What is meant by secondary storage? Mention some secondary storage devices.
Secondary memory also called backing storage is used to supplement the capacity of
main memory. The data in secondary storage is first brought into the main memory
before processing. Its purpose is to store the data and programs when the computer is
not using them. It can store large amount of data. It is also called nonvolatile, auxiliary
or the mass storage
Examples of secondary storage are Floppy Disk, Hard Disk, CDs, etc.
Q.2.11 What is meant by bus in computer system? How Data bus differs from an address bus?
Bus:
Communication between the microprocessor, memory chip and other chips that are
founded on the motherboard is done through a set of wires. This set of wires is called
the BUS. It provides an electrical path among CU, ALU, Memory and other hardware
parts on the motherboards.
The computer BUS is generally divided into three parts; Data Bus, Address Bus and
Control Bus.
i) Data Bus:
Data bus is used to transfer data from one device to another. Data bus connects the
CPU, memory and other hardware devices on the motherboard. The number of wires in
the bus affects the speed at which data can travel between components. Since each
wire can transfer one bit at a time therefore an 8 wires bus can move 8 bits or one byte
at a time.
ii) Address Bus:
The address bus that carries memory addresses is a set of wires similar to the data bus.
An address bus connects the CPU with memory. The reason that the address bus is
important is that the number of lines in it tells the maximum number of memory
addresses. For example, 8 bit data is enough to represent 2 8 = 256 different values. Thus
a CPU with 8-bit address bus could address only 256 bytes of memory.
Q.2.12 Describe the function of ports in a computer. How many types of ports are generally present
in a computer system?
Ans:
Ports:
Ports are the interface between processor and other Input / Output devices. Each I/O
device has a cable with a plug having several pins for plugging into a socket called port.
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The microprocessor communicates with I/O devices such as a keyboard and a monitor.
Port is generally provided as the back of a computer.
Most computers have several types of ports, each with different capabilities and uses.
But commonly there are two types of ports; serial port and parallel port.
i) Serial Port:
A serial port provides a connection for plugging a peripheral device with one data line
that carry one bit at a time. A serial port connects your computer to a device such as a
modem, which require two-way data transmission, or to a mouse which require only
one-way data transmission. Serial ports provide slow data transmission.
A serial port can have 9-pins or 25-pins. In personal computers serial ports are generally
designed as COM1, COM2, COM3 etc.
ii) Parallel Ports:
Parallel ports allow 8 bits data at a time over a cable with eight separate data lines.
Parallel ports can handle larger volume of data at a much faster rate as compared to
serial ports. Parallel transmission is used to send data to the printer.
The cable that connects two parallel ports contains 25 wires, 8 wires carry data and the
remaining wires carry control signals. In personal computer parallel ports are generally
designated as LPT1, LPT2, LPT3 etc.
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