Introduction to Computer PDF

# Introduction to Computer ## Definition of computer "An electronic device that receives data (inputs) and processes it by performing a set of operations (mathematical and logical) at high speed and infinitely accurate along with the ability to store huge amounts of data and information and retri...

# Introduction to Computer ## Definition of computer "An electronic device that receives data (inputs) and processes it by performing a set of operations (mathematical and logical) at high speed and infinitely accurate along with the ability to store huge amounts of data and information and retrieve them (outputs) when needed according to specific conditions". ## Computer Characteristics * It consists of many parts connected to each other, which work as one unit. * Depends on receiving inputs (data) through special devices (input units). ## Comparison between computers and humans ### 5 Stages of computer development - **The first stage: the early historical stage** - In this stage, attempts to develop machines that help in performing mathematical operations in an easier way. - The Arab counting system was distinguished by the presence of zero, unlike the Roman counting system, which did not contain zero. ### First: the first generation (1945-1958) - vacuum tubes * The first computers of this generation were the computer called ENIAC, then the computer appeared EDVAC, followed by the computer EDSAC and finally the computer called UNIVAC. #### First-generation computer features * The use of vacuum tubes technology in design and construction. * The size of these computers was very large and weighed heavily. ### Second: the second generation (1959-1964) - the transistor * In this generation, the transistor technology was used as a substitute for vacuum tubes which were smaller and longer in life and did not consume high electrical energy. This was the beginning period for appearance of some high-level programming languages. #### Second-generation computer features * The use of transistor technology in design and construction. * The size of these computers is smaller than the first generation. ### Third: The third generation (1964-1970) - Integrated circuits * Made of silicon wafers was used in the manufacture of computers. Accordingly, it has become much smaller than its predecessors, with a huge increase in speed. #### Third-generation computer features * The use of integrated circuit technology in design and construction. * The emergence of some high-level programming languages, such as "PL/1", "Algol68" and "Lisp". ### Fourth: The fourth generation (1970-1995) - microprocessors * In this generation, the microprocessor appeared, which represented a major revolution in the world of computer design. #### Fourth-generation computer features * The emergence of very small processor technology. * Read Only Memory (ROM) and Random Access Memory (RAM) appeared. ### Fifth: The fifth generation (1995-until now) - portable smart devices * The emergence of many high-level programming languages, such as C, Pascal, C++ and Prolog. * The computers of this generation provide a significant increase in productivity, as multicore processors appeared, and computer speeds increased to very high capabilities. #### Fifth generation computers features * The emergence of multi-core processors, which led to a huge increase in speed. * Increased storage capacity, and the emergence of new storage media such as CDs and Flash memory. ## Types of computers ### Types of computers by size * Computers have evolved over time and their sizes have changed from giant and super-power to lesser sizes with a significant increase in capabilities. #### First: Supercomputers * It is the largest computers. Until recently, it was the preserve of the major countries only due to its huge potential. These computers are used in research centers such as the NASA Space Center. ##### The characteristics of Supercomputers * It has hundreds of thousands of processors working together (up to more than 100,000 processors). #### Second: Mainframe computer * Also known as central computers, this type of computer has been designed to serve the purposes of large corporations such as banks, factories, airlines, ministries, and major government agencies. ##### The characteristics of Mainframe * It can run more than one operating system on the same device. #### Third: Minicomputers * The average computer is smaller than the previous computers, and this computer is often used in companies and government institutions that deal with a large number of customers in order to accomplish their administrative or other transactions, such as postal centers, social security and major commercial centers. ##### The characteristics of Minicomputer * Medium in size and smaller than the previous ones. #### Forth: Microcomputers * It is the smallest in terms of size among other forms of previous computers, and the least in terms of processing and storage capabilities. These computers are divided into: 1. Desktop 2. Portable computers 3. Personal Digital Assistant (PDA) 4. Tablets ##### The characteristics of Microcomputer * Small in size and light in weight. * There are many forms, including desktop, laptop, personal assistant, tablet, smart phone devices, etc. ### Types of computers by type (processing method) * Computers are divided by type or method of internal processing of the data that they process into: 1. Digital Computer 2. Analog Computer 3. Hybrid Computer #### Types of computers according to the purpose * Computers can also be divided according to the purpose for which they can be used as follows: 1. General Purpose Computers 2. Special Purpose Computers #### Types of computers according to the method of implementing the instructions * First: computers with serial processing * Second: computers with parallel processing * The use of parallel technology in designing software or hardware helps in achieving the following advantages: * High speed * Reliability or reliability * Decentralization #### Types of computing * First: distributed system * Second: grid computing * Second: cloud computing ##### Examples of cloud service: * E-mail services such as: Gmail and Yahoo mail * Drop Box Cloud Storage services, such as Google Drive * Among the most important global companies that contributed to the spread of cloud computing: Amazon, Google, and Microsoft. * Cloud computing requirements: * A personal computer. * Internet browser. * There are a number of free services that can be availed free of charge. ## Computer system components * First: Hardware * Second: Software * Third: Humans * They are the people who deal with the computer and can be divided into three main sections: * End users * Programmers * Maintenance technicians * They are the persons responsible for computer maintenance. * Fourth: Data and information * The data is the raw material that is processed inside the computer, which is often in the form of various inputs (text - numbers - symbols - pictures - sound..etc), for example student's grades in different courses. * As for the information, it is the product of processing and running data that gives added value to the user such as the student's total score or grade.