Wearable Computing Devices
All machines, components or devices that contain embedded, specialised computers are called computing devices. For example ATM machine, Digital alarm clock, Digital washing machine, Microwave oven, Toys, Cell phones, CD player, etc. are computing devices. All these devices Contain embedded Computer chips which allow these devices to do special computing for example the Computer of ATM machine gives banking transactions facilities, the computer of Digital alarm clock sets the time for alarm and manages calendar, and the computer Digital washing machine can be programmed to wash clothes.
• BASIC OPERATIONS OF A COMPUTER
Any computer system, regardless of its size, is capable of performing.
input operation: Accepting data for processing from an input device. Processing operations: Performing arithmetic and logical operations. Arithmetic operations include addition, subtraction, multiplication and division while logical operations include comparison of different values and decision making.
Output operation: Sending results to an Output device. Storage operation: Writing data to a storage device such as hard disk or USB flash drive.
The purpose of a Computer system is to accept data, process it and as a result of
processing, produce output in the form of useful information. The input unit of computer presents
data to the processor for processing. The results of processing of the data are displayed on the monitor screen, printed on paper or sent to any other output or storage device.
CLASSIFICATION OF DIGITAL COMPUTERS
There are several factors that make computers different from each other. These factors are physical size, cost, speed, etc. Based on these factors, computers are classified into four categories.
• Mainframe computer
Super Computers are the largest, the most expensive and powerful computers. They are used to process complex Calculations as Well as designing and controlling of complicated machines, such as rockets and fighter planes. Supercomputers are also used in nuclear research and weather forecasting which requires huge amount of calculations to be performed at high speed. The best known supercomputers are built by Cray Inc. an American supercomputers manufacturers and IBM. In Pakistan Super Computers are used in many Organizations, like Atomic Energy Research Center.
• Mainframe Computer
These are larger, more expensive and more powerful Computers Compared to minicomputer but less powerful than supercomputer. They are used in large Corporations, banks, universities and scientific laboratories. Mainframes usually fill a large room because they include many types of peripheral devices.
A typical mainframe can execute about trillion instructions per second (TIPS) and can support thousands of users.
Some examples of mainframe are IBM’s zEnterprize EC12, EC 196 and HP 16500 Series.
These Computers are larger and more expensive than micro Computers. Minicomputer and its peripheral equipment can usually fill a small room.
Minicomputers can support hundreds of users at a time. Mini compute s are faster than microcomputers. They can execute billions of instructions per second (BIPS). These computers can process more data than micro Computers.
Minicomputers are widely used in industrial process control, scientific research and small business applications.
Due to advancement of technology, the difference between the performance of microcomputer and minicomputer is gradually decreasing. As a result, modern Micro Computers are replacing the more expensive minicomputers.
Examples of minicomputer are IBM System/36 and HP 3000.
Microcomputer, shown in Fig.1.6, is the smallest and least expensive computer. Its small size is a result of LSI (Large Scale integration) and VLSI (Very large Scale integration) technologies. A modern microcomputer can execute millions of instructions per second (MIPS). Although, this is very fast but it is much slower than minicomputers and mainframes.
A typical microcomputer consists of a Keyboard, a Mouse, a Monitor and System Unit. Micro Computers are used at home for personal use as well as for business applications. A large variety of software is available for use on microcomputers. A microcomputer can easily fit on desktop or in a briefcase in the form of laptop computer.