What is Computer System
Computers are available in different sizes and types. In this post, we will discuss the classification of computers on the basis of their size. We will also discuss some not-50-common input and output devices, such as bar code readers, magnetic ink character readers, and braille printers.
Classification of computers on the basis of size
On the basis of size, we can classify computers into five categories-mobile computers, microcomputers, minicomputers, mainframes, and supercomputers.
Mobile computers are the smallest computers designed to be carried around by users anytime anywhere. Laptops/ ultrabooks, netbooks, tablets, smartphones, e-book readers, personal data assistants (PDAs), portable media players (PMPs), and laptop-tablet hybrid are all mobile computers. Laptops are portable versions of desktop PCs whereas notebooks are smaller than laptops and usually do not have DVD drives as well as a USB port. Both laptops and netbooks are capable of running the same software. However, netbooks primarily focus on Internet access. An ultrabook is another category of laptops that is slimmer and lighter but is built to offer the same performance as a laptop.
Tablets are easy to identify. They come without a keyboard and mouse and are operated via a touchscreen. Smartphones are phones with wireless Internet connectivity. A PDA (Personal Digital Assistant) is also known as a palmtop computer. These hand-held devices can function as a cell phone, fax machine, personal organizer, and have the ability to connect to the Internet. A PMP (Portable Media Player) is an electronic device that stores and plays audio, images, videos, etc.
Laptop-tablet hybrids are mobile computing devices that combine typical features of both a tablet and a laptop in a single device. Laptop-tablet hybrids combine touchscreens with full-size keyboards. The touchscreen can be detached or flipped around so that it can be used as a tablet.
A microcomputer is a small computer that is used by one person at a time and it is small on other computers. The desktop computers that you see in most offices, schools, colleges, and homes are microcomputers. Desktop computers are also called personal computer or PC
Minicomputers are larger than microcomputers, typically the same size as a refrigerator Minicomputers first appeared in the 1960s. In the 1980s they got replaced by microcomputers, which had become smaller and more powerful with time. CDC 160A, MicroVAX 3100, and HP 2100 are examples of minicomputers.
Mainframes are big, powerful, and expensive multi-user computers.
Supercomputers are the biggest and most powerful computers. They often occupy an entire room. They can process trillions of instructions per second Government organizations and large industries use them for work that requires a lot of numeric calculations, such as weather forecasting. IBM’s Sequoia and Fujitsu’s K Computer are examples of supercomputers.
The physical components of a computer or system that we can feel are called hardware. Input and output devices, storage devices, and the Central Processing Unit are examples of hardware.
Input devices acknowledge the contribution from the client and convert it into a structure that the PC can comprehend. Markets, banks, and so forth, utilize particular info gadgets to gather a lot of information quickly. Let us consider a few special input devices.
Bar Code Reader
You may have seen bar codes pasted or printed on products like grocery items and clothes. A bar code is a unique combination of vertical bars that represents product information, such as price and place of manufacture. A cashier uses a bar code reader to scan the bar code on each purchased item, which gets input into the computer.
Magnetic Ink Character Reader
A magnetic ink character reader can scan by characters printed in magnetic ink. This makes them ideal for marking and identifying cheques.
Cheques usually have cheque number, bank code, and branch code printed in magnetic ink.
Optical Character Reader
The process first produces a digital image of the text. Character-recognition software is then used to convert this image into character codes that can be understood, stored, and processed by the computer, This technique is called optical character recognition, Optical Mark Reader An optical mark reader is a device which is capable of reading printed forms used in objective type exams, with boxes or circles that can be filled with a dark pencil or ink. When a light beam passes through such a form, the marked areas reflect less light than the unmarked ones. This way the optical mark reader recognizes the boxes or circles that are filled. It is commonly used for checking answer sheets of exams that have multiple-choice questions
Card readers are used for reading information stored on cards, such as magnetic stripe cards and smart cards. Credit cards are examples of magnetic strip cards. Information in the form of numbers and characters is magnetically stored on a magnetic strip.