UNIT NO.2
Components of Computer System
(Solved Exercise)
Tick (✓) the correct option.
Answers are given at the end of the book.
Briefly answer the following question:
1. What are input devices? Enlist any four.
Input devices are devices used to enter data in computer.
i. Keyboard ii. Mouse iii. Scanner iv. Microphone
2. Write a Short note on keyboard.
Keyboard is the most common and very popular input device. It helps to input data into the computer. The layout of the keyboard is like that of traditional typewriter, although there are some additional keys provided for additional functions.
3. Differentiate between mouse and joystick.
Mouse
Mouse is a cursor- control device having a small palm size box with a laser beam at its base, which senses the movement of the mouse and sends corresponding signals to the CPU when the mouse buttons are pressed. It is commonly used with computer system.
Joystick
joystick is used to move the cursor position on a monitor screen. It is a stick having a spherical ball at its both lower and upper ends. The lower spherical ball moves in a socket. The joystick can be moved in all four directions. It is mainly used in playing games.
4. How does a light pen work?
Light pen consists of a photocell and an optical system placed in a small tube. When the tip of a light pen is moved over the monitor screen and the pen button is pressed, its photocell sensing element detects the screen location and sends the corresponding signal to the CPU.
5. Write a note on monitor, enlist its types.
A Monitor is an output device that is also known as a Video Display Terminal (VDT) or Video Display Unit (VDU). It displays images, text, video, and graphics information generated by a connected system unit. It is like a TV but its resolution is higher than a TV.
There are three kinds of monitors:
i. Cathode-Ray Tube (CRT)
ii. Flat-Panel Display
iii. SMD LED Screen
6. Differentiate between Flat panel and SMD monitors.
Flat-Panel Display
A flat panel display is a display unit like LCD that use a thin panel design. These screens are lighter, thinner and portable easily. They also have higher resolution than older models.
SMD Monitors
The term “SMD” stands for Surface Mounted Device. It refers to the mounting method used in manufacturing electronic devices such as LEDs. Unlike traditional display devices SMDS are mounted on printed circuit boards using automated equipment.
7. Differentiate between primary memory and secondary storage.
Primary memory
Primary memory is also known as main memory. It is also referred as “Internal memory.” Processor directly accesses the primary memory using data bus. It has limited capacity and it is expensive. Examples of Primary memory are RAM and ROM.
Secondary Storage
Secondary storage referred as secondary memory. It is also called external memory. It is not directly accessible to CPU. It is cheaper and has larger storage capacity as compared to primary memory. Commonly examples of secondary memory is Hard Disk, SSD and USB Drive.
8. Differentiate between RAM and ROM.
RAM
“RAM” stands for “Random Access Memory”. It is also referred as short-term memory. It is a temporary storage memory. RAM is also called volatile memory because data in RAM is vanished when power is lost.
ROM
“ROM” stands for Read Only Memory. It is the long-term internal memory. ROM is “Non-Volatile Memory” because data stored in ROM retains even if power is lost.
9. How does SSD is better from HDD?
SSD is better from HDD because SSD uses flash based memory which is much faster than traditional Hard Disk. SSD has increased the speed of computer systems because it can access data rapidly as compared to magnetic plates used in HDD.
10. Write the functions of control unit in computer system.
Control Unit (CU) manages the entire functioning of the computer system. The Control Unit collects the data entered using the input unit, leads it on for processing and once that is done, the output is presented it to the user. Basically, the instructions taken, interpretation of entered data, issuing signals to execute the data and then finally retrieving the data is all done in the Control Unit.
Answer the following questions in detail.
1. What is scanner ? Why do we use it ?
Answer:
Scanner
Scanner is an input device, which works like a photocopy machine. It is used when some information is available on paper and it is to be transferred in the computer for further manipulation.
Scanner captures images from the paper and converts them into a digital form that can be stored in computer. These images can be edited before they are printed.
2. How does a barcode reader work?
Answer:
Bar Code Reader
Bar Code Reader is an input device used for reading bar coded data. Bar coded data is generally used in labeling goods etc. We can see Bar Code Readers in shopping Malls these days. Bar Code Reader scans a bar code image, converts it into an alphanumeric value, and sends this value to the computer.
3. What are sensors ? Where do we use them?
Answer:
Sensors
Sensors are input devices that record data about the physical environment around them. Sensors send data to a computer. They do not make judgments, decisions or control any output devices. There are different sensors available each designed to measure different physical properties. Some of these
sensors are below:
• Magnetic Field Sensor
• Motion Detector Sensor
• Sound Sensor
• Humidity Sensor
• Pressure Sensor
• Light Sensor
4. Write a note on CPU, discuss working of its different parts.
Answer:
Central Processing Unit
The Central Processing unit is the core of any computer system. It comprises of three major components which have been discussed below
. Memory Unit
. Control Unit
. Arithmetic and Logical unit
All these three units are elements of CPU and together help in the working and processing of data. It is also known as the “Brain of Computer”.
Memory Unit
Memory is basically a device that has the capacity to store information. A memory unit refers the amount of data that the memory can hold. We measure this storage capacity in terms of bytes. There are two basic types of computer memory which are:
. Primary memory
. Secondary memory/storage
Primary Memory
Primary memory is also known as main memory. It is also referred as “Internal memory.” Processor directly accesses the primary memory using data bus. It has limited capacity and it is expensive. Examples of Primary memory are RAM and ROM.
Secondary Memory/Storage
Secondary storage referred as secondary memory. It is also called external memory. It is not directly accessible to CPU. It is cheaper and has larger storage capacity as compared to primary memory. Commonly examples of secondary memory is Hard Disk, SSD and USB Drive.
Control Unit (CU)
Control Unit (CU) manages the entire functioning of the computer system. The Control Unit collects the data entered using the input unit, leads it on for processing and once that is done, the output is presented it to the user. Basically, the instructions taken, interpretation of entered data, issuing signals to execute the data and then finally retrieving the data is all done in the Control Unit.
Arithmetic and Logical Unit
As the name suggests, all the mathematical operations are performed in the Arithmetic and Logical Unit of the CPU. It can also perform actions like calculation a comparison of data and decision-making actions. The ALU consist of circuits using which additions subtraction, multiplication, division, less than, greater than, equal to and other numerical based calculation can be performed.
6. Can a computer work without secondary storage device? justify your answer.
Answer:
Yes, a computer can work without a secondary storage device, but its functionality and capabilities may be limited.
Primary storage, such as RAM (Random Access Memory), is essential for a computer to function. It stores data and instructions that the computer’s processor actively uses during its operation. However, primary storage is volatile, meaning it loses its data when power is turned off.
Secondary storage devices, such as hard drives, solid-state drives (SSDs), or external storage devices, provide non-volatile storage for the computer. They retain data even when the power is off, allowing for long-term storage of files, operating systems, applications, and user data.
In conclusion, while a computer can technically function without a secondary storage device, it would be severely limited in terms of data storage, software installation, data persistence, and data recovery capabilities. A secondary storage device is an essential component for most computer systems, providing long-term storage, data backup, and expanded storage capacity.
7. How does a computer work? Write down steps needed to convert data into information.
Answer:
Working of Computer System
Computer is an electronic machine which processes the data (input) to produce the desired information (output), and saves data (storage) according to the given instructions. A computer works by combining input, storage, processing, and output operations. All the main parts of a computer system are involved in these four operations.
Input: Input is the data before processing. It comes from input devices such as mouse, keyboard, microphone, and other external sensors.
Processing: In processing operation input is transformed into output, Central Processing Unit (CPU) is responsible for this operation.
Storage: The storage is how the computer saves input. Immediate processing is stored temporarily in the Random Access Memory (RAM) while hard drive is used for long-term storage.
Output: Output is the final result of data processing (information). You can also receive the output through a printer or a projector instead of directly through your monitor.
Write the functions of following:
ROM, RAM, ALU, CU, HDD, SSD
ROM
ROM stands for “Read Only Memory”. ROM is “Non-Volatile Memory” because data stored in ROM retains even if power is lost. It comes with pre-written programs by the computer manufacturers. It holds the instructions for booting-up the computer.
RAM
RAM stands for “Random Access Memory”. RAM is volatile memory because data in RAM is vanished when power is lost. RAM stores the currently processed data from the CPU and send them to other units. It is working place of computer.
ALU
ALU stands for Arithmetic and Logical Unit. As the name suggests, all the mathematical operations are performed in the Arithmetic and Logical Unit of the CPU. It can also perform actions like calculation a comparison of data and decision-making actions. The ALU consist of circuits using which additions subtraction, multiplication, division, less than, greater than, equal to and other numerical based calculation can be performed.
CU
Control Unit (CU) manages the entire functioning of the computer system. The Control Unit collects the data entered using the input unit, leads it on for processing and once that is done, the output is presented it to the user. Basically, the instructions taken, interpretation of entered data, issuing signals to execute the data and then finally retrieving the data is all done in the Control Unit.
HDD
The basic function of a Hard Disk Drive (HDD) is data storage. HDDs are used to store and retain digital data on a long-term basis. They provide a large capacity for storing various types of files, including operating systems, software applications, documents, media files, and more. HDDs offer non-volatile storage, meaning the data remains stored even when the computer is powered off, making it a reliable and persistent storage solution.
SSD
The basic function of a Solid State Drive (SSD) is also data storage, similar to a Hard Disk Drive (HDD). SSDs use flash memory technology to store and retrieve digital data. They offer fast access times and high data transfer speeds, making them ideal for improving system performance and reducing load times for applications and files. SSDs are commonly used as the primary storage device in modern computers and laptops due to their speed, reliability, and durability.