Computers

Computer is an electronic device which manipulates data on the basis of given instruction to it. In this we enter the data with the help of output devices and get information on input devices. The first devices that resemble modern computers date to the mid-20th century (1940–1945), although the computer concept and various machines similar to computers existed earlier. Early electronic computer were huge in size the size of that computer is almost cover the space of one room and they also consume the large amount of power. Modern computers are comparatively much smaller in size and they are based on tiny integrated circuit which helps in decreasing the size of computers. Therefore computers can perform complex and repetitive procedures quickly, precisely and reliably. Modern computers are electronic and digital.

Computers cover every area and industry now a day people are very dependable on it. Computers calculations are accurate and computer never makes mistake until the instructor don’t made any mistake. Programs makes computer versatile and distinguish them from computers. Programs are those which have ability to execute and store list of instructions. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.

Types of computers

Fundamentally there are two types of computers analog and digital computers. Analog computers are those which solve problems on the basis of continuously changing data such as temperature, pressure and voltage. Digital computers solve problems by manipulating discrete binary digits in 0’s or 1’s form.

Apart from this, computers are also categorized on the basis of physical structures and the purpose of their use. Based on Capacity, speed and reliability they can be divided into three categories of computers

1 The Mainframe Computer: also known as supercomputer. This computer allows many simultaneous users. Supercomputers are very expensive and these are the fastest computers currently available. These operates on immense amount of mathematical operations like scientific calculations and they are use in area’s like weather forecasting, nuclear energy research, electronic design and analysis of geological data.

2 The Mini computer: A minicomputer is a multiprocessing system capable of supporting from up to 200 users simultaneously. Minicomputers are also used for the large business organization like mainframe computers. Its used for accounting, billing and inventory operations. Minicomputers are more powerful but still compatible version of a personal computer

3 The Microcomputer: These are the most frequently used computers better known by the name of “Personal computers”. This is the type of computer meant for public use.

• Desktop: A computer designed to fit comfortably on top of a desk, typically with the monitor sitting on top of the computer. Most desktops offer more power, storage and versatility for less cost.
• PDA: This term expand as personal digital assistant. It’s a handheld device that combines computing, telephone/fax, and networking features. Mostly PDAs are pen-based, using a stylus rather than a keyboard for input. PDAs are also called palmtops, hand-held computers and pocket computers. It has feature of handwriting recognition and now some PDAs also have the feature of voice recognition.
• Hand Held Computer: A portable computer that is small enough to be held in one’s hand. Although extremely convenient to carry, handheld computers have not replaced notebook computers because of their small keyboards and screens. With the feature of personal information manager like calendar and address book makes hand held computers most popular.
• Server: A computer that has been optimized to provide services to other computers over a network. Servers usually have powerful processors, lots of memory and large hard drives. Examples of server applications include web servers, e-mail servers, database servers, and file servers.
• Towers: Tower models are those in which motherboard, power supply and mass storage devices are stacked on top of each other in one cabinet. The main advantage of tower models is that there are fewer space constraints, which makes installation of additional storage devices easier.
• Work Stations: A computer that has a more power resources like Processing Power, Memory and additional capabilities to perform special task refers to as workstation. It is a type of computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other types of applications that require a moderate amount of computing power and relatively high quality graphics capabilities. In networking, workstation refers to any computer connected to a local-area network. It could be a workstation or a personal computer.
• Laptops: A small, portable computer -- small enough that it can sit on your lap. Nowadays, laptop computers are more frequently called notebook computers. Laptops integrate the display, keyboard, a pointing device or trackball, processor, memory and hard drive all in a battery-operated package slightly larger than an average hardcover book.
• Wearable: wearable computers are the latest trend in computing these are those computers which can be worn on the body. Wearable computers are especially useful for applications that require computational support while the user’s hands, voice, eyes or attention are actively engaged with the physical environment.