CHAPTER 1 REVIEW FROM CLASS-1 TOPICS COVERED Features of Computer | Types of Computer | Application areas of Computer Hardware definition | Software definition | What is Input - Processing - Output? Input and Output devices | CPU, Motherboard and Peripherals Computer is a machine, which manipulates data according to a list of instructions. Computer has many features: • It works on electricity. • It makes our work easy. • It is very fast. • It never gets tired. • It never makes mistakes. • It never forgets anything. 5 TYPES OF COMPUTER The various types of computer are: Desktop The computer that sits on the desk/table is called desktop computer (or simply a desktop). These are most commonly known as Personal Computers (or PCs). PCs are not designed to be portable. This means that they cannot be moved from one place to another easily. Portable (Laptop/Notebook/Netbook) computers Portable computers are meant for users who are frequently on the move. These are light-weight mobile computers, also known as portable computers or laptop/notebook/ netbook computers. They have a single unit having monitor, keyboard, a pointing device or trackball, CPU, memory and hard drive. They operate on battery. Palmtop Computers These are integrated computers that often use small memory and storage space. Palmtop computers usually do not have keyboards but rely on touchscreen technology for user input. These are very light-weight with a reasonable battery life. A slightly larger and heavier version of the palmtop computer is the hand-held computer. 6 Mainframe Mainframe refers to large computers which are very powerful and are used for special applications. Supercomputers Supercomputers are extremely large and even more powerful computers and are used for weather forecasting, national defence applications, etc. They are built using hundreds or thousands of processors. Wearable computers The latest trend in computing is wearable computers. Common computer applications (e-mail, accounts, multimedia, calendar/scheduler, notes) are integrated into watches, cell phones, shoes, specs and even clothing! Examples of wearable computers includes wrist watches, smart glasses, etc. What you can do with a computer? You can do a variety of jobs on computer: • You can create and store your documents. • You can do big calculations on computer. • You can play games on computer. • You can make drawings on computer. • You can play music and movies on computer. 7 Any computer consists of two main components: 1. Hardware 2. Software Hardware Hardware is all those parts of computer that you can actually touch and feel like CPU, monitor, keyboard, mouse, speakers, power supply, cables, etc. Software Software is a list of instructions, which is used to control hardware to achieve useful results. Linux Input Any Data / Information we feed in computer is called input. EXTRA INFO : WHAT IS DATA When you type a number or a letter in computer it is called data. Memory Memory is the place where computer stores the input data or processed data before, after and while processing. There are two types of memory: 8 1. Primary (Temporary) memory (also known as RAM) 2. Secondary (Permanent) memory (hard disk drive) Output After processing the input data, computer gives the result, which is called output. Processing It is the process of manipulating data stored in the memory as per the instructions. 2 + 3 = 5 Input Devices Input devices are used to feed data / information into the computer. Some input devices are: • Keyboard • Mouse • Web Camera • Microphone • Stylus Pen 9 Output Devices The devices used for displaying the input or processed data / information are called output devices. Some of the output devices are: 1. Monitor (VDU) 2. Speakers 3. Printers CPU CPU stands for Central Processing Unit. It is the brain of the computer which does all the calculations. It is also called processor. It is the most important part of the computer. CPU is placed on the motherboard. CPU and motherboard are placed inside the cabinet. Motherboard Motherboard is the main circuit board where all the components like CPU, monitor, memory, keyboard, mouse, etc. are connected. Apart from main CPU, it has many other processors which help the main CPU to control and communicate with other parts of the computer. Peripherals The term “peripherals” is used to refer to components that add functionality of a computer system. With the help of peripheral devices, you can interact with the computer. Examples of peripherals are: Mouse, Keyboard, speakers, web camera, etc. 10 CHAPTER 2 TYPES OF SOFTWARE TOPICS COVERED What is software? | Categories of software What is programming language? | Categories of programming language Many times while dealing with computers, you come across a term called ‘software’. Do you know what software means? SOFTWARE Software refers to a list of instructions, which are used to control the computer hardware. It is also called a program or an application. Computer software can be broadly classified into two categories. They are: 1. System Software 2. Application Software 11 System Software System software directly “talks” USER to the computer hardware and gets the job done. It provides an interface between the hardware APPLICATION and other types of software. SOFTWARE Operating System (OS) is one of the most used system software. It instructs hardware to perform calculations in the machine OS SOFTWARE language/binary language. OS takes data input and translates it into the machine/binary language HARDWARE so that the hardware can process and manipulate it. The software then takes the result (output) from the hardware and converts it back to a language like English, Hindi, French, etc. that the user understands. Thus, the OS software can be well understood as a “translator” for application software to talk to the hardware. Apart from translating, it also manages the available resources like the CPU, memory, keyboard, mouse, etc. DID YOU KNOW? DOS (Disk Operating System) was a very popular software, marketed by Microsoft. It is completely obsolete now. No one uses it anymore. Use of DOS was discontinued in favour of new features and ease of use in Windows. Linux Mac OS X Windows 8.1 12 Some of the most popular OS software for computers are Microsoft Windows, Linux, Unix, Mac OS, etc. You will study about Microsoft Windows 8.1 in the coming chapters. Application Software Unlike the System software, the Application software interacts directly with the user. The application software takes the data input from the user and shows the processed result (output) to the user. It rides over the OS software to control the hardware to do all the processing and manipulation of the input data. EXTRA INFO : SOFTWARE INSTALLATION To use either OS software or Application software, you need to first install it. The process of putting the software in the computer is called installation. Installation has to be performed under the supervision of a teacher or software engineer. PROGRAMMING LANGUAGE You know that software refers to a list of instructions. The special languages in which these instructions are written are called programming languages. Programming languages have very strict rules which describe their structures and PASCAL meanings. There are thousands of programming languages and BASIC C++ new languages are created almost every year. 13 The computer programming language can be divided into two groups. These are: 1. Low-level programming language 2. High-level programming language Low-level programming language Low Level The language which the computer ASSEMBLY Languages hardware understands directly is known 0 1 0 1 0 as low-level programming language. This 0 1 0 1 0 0 1 0 1 0 language primarily deals with two digits, i.e. 0 and 1, hence, it is also called binary 0 1 0 1 0 language or machine language. Machine languages are very difficult to learn and use. Some examples of low level languages are Assembly, Machine code, etc. Some parts of OS software are written in low-level programming languages. High-level programming language High Level VB, Pascal Languages A high-level programming language is relatively closer to the languages we SPECIAL SOFTWARE KNOWN AS COMPILER / INTERPRETER speak. They are easier to understand 0 1 0 1 0 and use. Some examples of high-level 0 1 0 1 0 0 1 0 1 0 programming languages are Visual Basic, Pascal, FORTRAN, C, C++, etc. 0 1 0 1 0 Application software is written in high- level programming languages. EXTRA INFO : LOW LEVEL OR HIGH LEVEL The words low level and high level do not mean that these languages are inferior or superior to each other. They just describe how closely they deal with the computer hardware. 14 POINTS TO REMEMBER • System Software controls the hardware and gets the job done. • Application software sits over OS software to control hardware to do all the processing. • Low-level programming language is close to machine language or binary language. • Hardware components talk to each other in machine or binary language consisting of 0s and 1s. • High-level programming language is close to the English language we speak commonly. 1 PRACTICE TEST A. Fill in the blanks with the help of clue words: Application Software Binary language Translator Low-level System Software 1. ..................... is a language of 0’s and 1’s. 2. Operating system software acts as a ..................... for application software to talk to the hardware. 3. ..................... interacts directly with the user, takes input and shows processed results. 4. ..................... provides an interface between the hardware and software. 5. Computer hardware can directly understand ..................... language. B. Write (T) for True or (F) for False: 1. Windows 8.1 is an application software. 2. Application software rides over the operating system software. 3. System software directly interfaces with hardware and gets the job done. 4. User gives instructions to the computer in low-level programming language.