Unit I - (Computer fundamentals) Computer: Computer is an electronic device which manipulates the data according to the list of instructions. A computer is used as a data processor which converts data into information. Computers can solve highly complicated problems quickly and accurately. They can perform a lot of tasks such as online reservations, playing games, controlling flight timings, traffic and weather forecasting etc. Computerization has been done in business, banking, electronic publishing, engineering, creative designing, fashion designing etc. Data and Information: Data: In terms of computers, data means raw facts and figures. For example, +,2,4,6,=, etc. Whereas Information is the meaningful content which is extracted from data i.e., raw facts and figures. For example, 2+4 = 6 here, 6 is the information. Evolutions/History of computers: Evolution of computers refers to the historical developments through which computers and technology have passed, from the time they started to exist(in ancient forms) to their current state. 1. ABACUS Many centuries ago when man started to count the numbers, he thought of a device which can trace the numbers and thus came the existence of ABACUS. It was the first counting device which was developed in China more than 3000 years ago. The name Abacus was obtained from Greek word Abax which means slab. This device basically consists of a rectangular wooden frame and beads. 2. Napier ’s Bones It is a device which contains a set of rods made of bones. It was developed by John Napier, a Scottish Mathematician and hence the device was named as Napier’s Bones. The device was mainly developed for performing multiplication and division. Later in 1614 he also introduced logarithms. 3. Pascaline Pascaline is a calculating machine developed by Blaise Pascal, a French Mathematician. It was the first device with an ability to perform additions and subtractions on whole numbers. The devices made up of interlocked cog wheels which contains numbers 0 to 9 on 1 its circumference. When one wheel completes its rotation the other wheel moves by one segment. 4. Babbage’s Difference and Analytical Engine Charles Babbage was an English mathematician. In 1822, he designed a machine called difference engine. This machine was used to calculate and print mathematical tables. The analytical engine was capable of performing all four arithmetic operations as well as comparison. It is also called pioneer computer. Hence, Charles Babbage is rightly known as the Father of computer. 5. Punched Card System Punched Card System is used for storing and retrieving data. This was invented by Herman Hollerith, an American Statistician in US Census Bureau. The system stores the data coded in the form of punched holes. 6. Mark-1 In 1943, Prof. Howard Aiken of U.S.A. constructed an electro-mechanical computer named Mark-1 which could multiply two 10 digit number in 5 second- a record at that time. This was the first operational general purpose computer. Generations of computer: First Generation(1940-1956) The computers in this generations were very large in size and their programming was a difficult task. Examples are ENIAC, EDVAC etc. Characteristics of First generation computers: i. Vacuum tube was core element. ii. Punched card and paper tape were secondary memory. iii. Generate considerable heat and poor reliability. iv. High electricity consumption v. Machine and symbolic language programming. Second Generations(1956-1963): In this generation, the transistor was invented in 1947, and the vacuum tubes was replaced by the transistor. Transistor helped computers to become smaller, faster, cheaper, more energy- efficient and more reliable than their first-generation predecessors. Examples are IBM- 700, ATLAS etc. Characteristics of Second generation computers: i. Transistor circuit used as core element. ii. Magnetic core primary storage. iii. Required less power to operate and more reliable. iv. Computers programmed in assembly and machine languages. v. Smaller compared to first generation. 2 Third Generation(1964-1971): The third generation of computers is marked by the use of Integrated Circuits(ICs) in place of transistors. A single IC has many transistors, resistors and capacitors along with the associated circuitry. Examples include IBM/360/370, NCR 395 etc. Characteristics of Third generation computers: i. Increased miniaturization, speed and reliability. ii. Development of minicomputer. iii. Magnetic disk secondary storage. iv. Better storage devices(tapes). Fourth Generations(1972-present): Large Scale Integrated(LSI) Circuits and Very Large Scale Integrated(VLSI) circuits were emerged in the fourth generation of computers. These circuits are packed about thousands of transistors in a single chip. Examples include Intel 4004. Characteristics of Fourth generation computers: i. One advancement was the development of personal computers through which costs came down rapidly. Floppy disks served as a low cost, high capacity backup peripherals. ii. Higher storage device than earlier generations. iii. Development of microcomputer or personal computer. iv. More speed than earlier generations. Fifth Generation(Present and Beyond): In the fifth generation, the VLSI technology became ULSI(Ultra Large Scale Integration) technology resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and superconductor, which help to make artificial intelligence a reality. All the higher level languages like C and C++ are used in this generation. Characteristics of Fifth generation computers: i. Organic chips ii. Decreasing cost of software and hardware. iii. Large data storage facility. iv. Artificial intelligence. v. High speed processing. Functional unit of computer: The basic organizations of a computer system includes four major functional units CPU, Input unit, Output unit and storage devices. The block diagram of basic computer system is shown below: 3 CPU (Central Processing Unit) Input Unit Output Unit CU (Control Unit) ALU (Arithmetic Logic Unit) Primary Storage Secondary Storage Basic organization of computer system A) Input Unit: The following functions are performed by an input unit: i) It accepts (or reads) the instructions and data from the outside world. ii) It converts these instructions and data in computer acceptable form because a computer can understand only binary symbols(i.e. 0 and 1) iii) It supplies the converted instructions and data to the computer system for further processing. B) Output Unit: The following functions are performed by an output unit: i) It accepts the results produced by the computer, which are in coded form(i.e., in binary form), and hence , cannot be easily understood by us. ii) It converts these coded results to human acceptable(readable) form. iii) It supplies the converted result to the outside world. C) Storage Unit: The following functions of the storage unit are to hold: i) The data and instruction required for processing , received from input devices. ii) Intermediate results of processing. 4 iii) Final results of processing, before these results are released to an output device. The storage unit of all computers is comprised of the following two types of storage: 1. Primary storage 2. Secondary storage D) Central Processing Unit(CPU): Sometimes CPU is only referred to as the central processor, but more commonly called only processor, the CPU is the brain of the computer where all or most of the calculations take place. In terms of computing power, the CPU is the most important element of a computer system. Two typical components of a CPU are the following: i) The Arithmetic Logic Unit(ALU), performs arithmetic and logical operations. ii) The Control Unit(CU), extracts instructions from memory and decodes then executes them. a) Arithmetic Control Unit(ALU): The ALU of a computer system is the place, where the actual execution of the instructions takes place, during the processing operation. To be more precise, all the arithmetic(+, -, x, /) and logical(<, >, ==, <=, >=) operations are performed in ALU. b) Control Unit(CU): It does not perform any actual processing on the data, the control unit acts as a central nervous system, for the other components of the computer system. It manages and co-ordinates the entire computer system. Also, it controls and guides the operations like a supervisor. It obtains instructions from the program stored in main memory, interprets the instructions and issue signals which cause other units of the system to execute them. There are input devices are explained as under: 1. Keyboard: A computer keyboard is one of the primary input devices used with a computer. Similar to an electric typewriter, a keyboard is composed of buttons that create letters, numbers, and symbols, as well as perform other functions. 2. Mouse: A computer mouse is a handheld hardware input device that controls a cursor in a GUI (graphical user interface) and can move and select text, icons, files, and folders on your computer. 3. Scanner: A scanner is an input device that scans documents such as photographs and pages of text. When a document is scanned, it is converted into a digital format. This creates an electronic version of the document that can be viewed and edited on a computer. 4. Barcode reader: Customers new to barcoding typically ask, "What is a barcode scanner?" The answer is simple: A barcode scanner—also known as a barcode reader— is an electronic device that decodes and physically