6 April 23 Computer system class 9

 Computer System (chap-1)

 1. Computer- A computer is an electronic device that can perform a variety of operations according to a set of instructions called program

2. Hardware- Hardware refers to physical parts of the computer that can be touched physically.

3. Software- Software refers to the instructions that tell the computer what to do

4. Data- Unprocessed raw facts and figures are data e.g., a name (Ram), some marks (72.5%), a year (2020) etc. are data.

5. Information- It refers to the processed data that is meaningful e.g., above data can be converted into information as “Ram, who passed in 2020, secured 72.5% marks.”

6. Functional components of a computer system A computer, mainly, has four functions 1. Accepts data- data 2. Processes data- Processing 3. Produces Result/Output- Output 4. Stores Results- Storage

Convergence of technology is the interaction of two or more different technologies in a single device or system.

eg. ICT, Smart phone, mobile tv etc. 

LONG Q/ANS:-

 Convergence of Technologies:- The process by which existing technologies merge into new forms that bring together different types of media and applications. e.g., the convergence of information and communication technologies has led to a new technology term- ICT. Smartphone are an excellent example of technological convergence, as they provide functions of different technologies like telephone, cameras, gaming, audio/video players, webcasting, audio/video conferencing, internet streaming etc. in one product. Other examples of convergent technologies are VOIP, SmartTV, Mobiel TV etc.

CPU- The computer’s Brain The CPU is also called the microprocessor or simply the processor. CPU controls and directs the internal activities and actions of a computer. A CPU does the entire thinking and controlling in a processing action. All other parts of a computer work as directed by the CPU. 

The CPU consists of three basic sections:- 

1. The ALU(Arithmetic Logic Unit)- This unit performs the arithmetic operations i.e. addition, subtraction, multiplication and division. All logic operations which involves comparisons such as less than, greater than, or equal to.

2. Control Unit(CU)- The control Unit of the CPU directs the entire computer system to carry out, or execute, stored program instructions.

3. Registers- All data is temporarily stored in registers during execution of programs. Registers offer very fast memory but very limited in size. 

Characteristics of a Computer:-

 Strengths of Computers

1. Speed 2. High Storage Capacity 3. Accuracy

 4. Reliability 5. Versatility. 

Weaknesses of Computers 

1. Lack of Decision Making Power 

2. IQ Zero 

3. No Heuristics(Heuristics means learning from past experience) 

Types of computers 

Purpose Wise:- 

1. Special purpose computers- Perform specific tasks Only. 

 2 General purpose computers- can perform a variety of tasks depending on the program given. 

Principle of Operaion:- 1. Analog Computers- Work with continuous physical quantities like voltage, current, temperature etc. i.e., take input in the form of volts, ampere, Celsius etc.

2. Digital Computer- Work with digital data i.e. discontinuous data (converted in the form of 0, 1 etc.) 

 3. Hybrid Computers- Combination of digital and analog computers.

Digital computers configuration wise categories:- 

1. Embedded computers 2. Personal/Desktop computers 3. Mini Computers 4. Mainframe Computers 5. Supercomputers

Q1. Multiple choice questions:- a. The physical components of the computer system are called ………………

 i) Software ii) Hardware iii) Firmware  

b. Which one is the device that is the ‘brain’ of a computer system?

 i) CPU ii) Motherboard iii) Scanner

c. Out of these which one is a volatile memory? 

i) ROM ii) RAM iii) Floppy

d. A byte consists of …………… bits. i) 2 ii) 4 iii) 8 

e. The smallest unit of data in a computer is………….. 

i) Bit ii) Byte iii) nibble

f. 1 Gigabyte (GB)=…………….MB

 i) 100 ii) 1000 iii) 1024

g. Unprocessed raw facts and figures are known as

 i) Information ii) Storage iii) Data 

h. Set of instructions given to computers are called a …….. 

i) Program ii) Data iii) Icon 

Q2. Fill in the blanks:- 

a. Computers have …ZERO…..IQ. 

b. …Supercomputer..is the most powerful computer.

 c. Data are the raw facts from which information are derived. 

d. ALU stands for…Arithmetic logic Unit.

 e. The processed and meaningful form of data is called Information. 

Q3. What are the major strengths and weaknesses of computer? 

Ans3- Strengths1. Speed 2. Accuracy 3. Reliability 4. Versatility 5. High storage capacity

 Q4. What is computer program? 

Ans4- A computer program is a set of instructions given to computer to perform some operations.

 Q5. Which type of computer provides a user with mobility as well as essentially the same processing capabilities as a desktop personal computer?

 Ans5. Laptop computers or notebooks provide user mobility as well as essentially the same processing capabilities as a desktop personal computer

Q6. Which of the following are parts of computer i.e. hardware and software? 

Hardware- CPU, control unit, ALU, Processor, Memory

 Software- Operating system, windows XP, Query

CHAPTER 2

Cloud Storage - Cloud storage means "the storage of data online in the cloud," wherein a data is stored in and accessible from multiple distributed and connected resources that comprise a cloud. Cloud storage can provide the benefits of greater accessibility and reliability; rapid deployment; strong protection for data backup, archival and disaster recovery purposes. Examples: – Google Drive , one drive, Microsoft Sky Drive.