Tiêu đề Module 2-Evolution of Computer_part 2.pdf ✅

Classification of Computer Systems a. On the basis of Technology • Generations of computers Each generation of computer is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly (smaller, cheaper, more powerful, more efficient and reliable devices). First Generation Time Period : 1940's-1950's Technology Used : Vacuum Tubes Size and Speed : Huge, taking up entire rooms, Slow speed Language Used : Machine language Cost : System and working cost very high. Other Features • Used a great deal of electricity. • Generated a lot of heat. • Input was based on punched cards and paper tape, and output was displayed on printouts. Example: UNIVAC and ENIAC Second Generation Time Period : 1950's- 1960's Technology Used : Transistors Size and Speed : Lesser size and increased speed Language Used : Assembly language and languages like COBOL and FORTRAN Cost : Cost decreased Other Features : More efficient and reliable. Though the transistors still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output. Example : UNIVAC 1108, IBM 1401, CDC 1604 Third Generation Time Period : late 1960's-1970's Technology Used : Integrated Circuit Size and Speed : Size Lesser and speed further increased Language Used : Operating System was developed. Cost : Cost decreased further Other Features : Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory.Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors. EXAMPLE : IBM-360 series, Honeywell Model 316, Honeywell – 6000 series, CDC – 1700. Fourth Generation Time Period : 1970's-today Technology Used : Microprocessor Size and Speed : Reduced size and tremendous speed Language Used : High Level Languages like PASCAL, COBOL, C, C++, JAVA Cost : Reduced Cost Other Features : Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors. As these small computers became more powerful, they could be linked together to form networks, which eventually led to
the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices. Example : Intel 4004, Apple Macintosh Fifth Generation Time Period : 1990's –today Technology Used : Microprocessor Size And Speed : Reduced size and tremendous speed Language Used : Based on Artificial intelligence Cost : Reduced Cost Other Features : Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today.The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization. Example : Parallel Inference Machine Note: • Artificial Intelligence is the branch of computer science concerned with making computers behave like humans. • Voice Recognition is the field of computer science that deals with designing computer systems that can recognize spoken words. b. On the basis of Purpose • According to Purpose – whether the computer is general purpose or special purpose these computers are designed to handled a variety of different problems to meet different needs. • General Purpose computer – can store different programs and performs variety of functions such as inventories, payroll, billing etc. They are strong in versatility but are normally weak in speed and efficiency. Example: Personal Computer Examples: Desktop computer, Laptop Computer • Special Purpose computer – these computer are designed to handled specific problem or to perform a specific task. Special purpose computers are those used for collecting highway tolls, airline reservation, satellite tracking, air traffic control and industrial process control. Examples: ATM Machine, Washing Machine, Cash Registers etc. c. On The basis of size & Speed The current classifications of computers place them into four categories: 1. Super Computers • The fastest type of computer. • Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations. For example, weather forecasting requires a supercomputer. • Other uses of supercomputers include animated graphics, , nuclear energy research, and petroleum exploration.
Characteristics: • Powerful • Expensive • Dedicated to one purpose - weather, satellites, military • Used by large governments or very large companies • Can be used by thousands of people at the same time • Very large - fill rooms 2. Mainframes • In the early days of computing, mainframes were huge computers that could fill an entire room or even a whole floor. • is a large computer system characterized by several banks of internal storage, multiple input/output devices and magnetic disk and tape storage. • Most of the mainframe computers have the capacities to host multiple operating systems and can handle hundreds of users (can serve up to 50,000 users simultaneously) Characteristics: • Expensive • Powerful and fast • Is not limited to one job • Used by business and small government organizations The main difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs simultaneously. 3. Minicomputers • Another term rarely used anymore, minicomputers fall in between microcomputers (PCs) and mainframes (enterprise servers). • Minicomputers are normally referred to as mid-range servers now. Characteristics: • Smaller than mainframe • Can do several jobs at once • Can be used by many people at one time • Used by small companies 4. Microcomputers (Personal Computers) • is a computer with a microprocessor as its central processing unit. They are physically small compared to mainframe and minicomputers. Many microcomputers (when equipped with a keyboard and screen for input and output) are also personal computers (in the generic sense). • also called personal computers (pc’s) because they are designed to be used by one person at a time. Classification within this category includes: 1. Desktop • are the most common type of personal computer and are designed to fit conveniently on the surface of a desk or workspace. Desktop computers have separate display screens. A workstation is simply a desktop computer that has a more powerful processor, additional memory and enhanced capabilities for performing a special group of task, such as 3D Graphics or game development. Deep Blue computer play a chess game against Garry Kasparov in 1997, it is an IBM supercomputer that uses scalable parallel processing to solve complex problems. Deep Blue uses 256 processors working together to calculate between 50 and 100 billion chess moves in under three minutes.
2. Laptop • also called a notebook, is a personal computer for mobile use. • A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device (touchpad or trackpad) and speakers into a single unit. • Powered via an AC adapter, and can be used away from an outlet using a rechargeable battery. Classification: ✓ Desktop replacements ✓ Subnotebook ✓ Netbook ✓ Rugged ✓ Tablet PC Forms: • Slate • Convertible • Hybrid 3. Handheld • mobile device (also known as a handheld device, handheld computer or simply handheld) is a small, hand-held computing device, typically having a display screen with touch input and/or a miniature keyboard. Typical handhelds: • Information appliance • Smart phone/Mobile Phne • Personal digital assistant (PDA) • Personal Communicator • Handheld game console 4. Video game consoles • is an interactive entertainment computer or modified computer system that produces a video display signal which can be used with a display to display a video game 5. Embedded computer • “Computers on a chip”. A microprocessor or a microcontroller, which is programmed to perform a small number of tasks. • are the “brains” behind many everyday mechanisms, such as wireless devices, cars, climate control systems, traffic signals, and washing machines, ticket machines at the subway, cameras, airplanes, cars, sewing machines, clocks, etc. • The software written for many embedded systems is called firmware. Firmware is software that is embedded in hardware devices, e.g. in one or more ROM or Flash memory IC chips. d. On the basis of how it functions Analog Computer • Operate on continuous data, like measuring temp. changes • Faster • Accuracy of an analog computer is restricted to the accuracy with which physical quantities can be sensed and displayed. • Specific Purpose computers