{text-indent:blink}Pascal language | C | PHP | Java
What is Computer?
A computer is a machine that accepts data at its input, processes data according to predefined rules i.e. sequence of calculations and/or decision, supplies the results(output) in the form of Data or Actions and stores data.
Italic words tells us the major components of computers which are:
Input devices-Provides the means for computers to receive program instruction and data from user or other devices. e.g. Keyboard, Scanner etc.
Processing devices-Controls the operation of the Entire System, it is made up of Arithmetic Logic Unit(ALU) that performs all the arithmetic and logic in nature operations and Control unit(CU) that fetches instruction from memory, decode them and direct the system to execute the operations + controlling the flow of instructions and data to/from the storage devices to the input or output devices.
Output devices-Provide the means for the computer to return the solution to the user or other devices. e.g. Monitor, Printer etc.
Storage devices-section of computer that stores information. comprises of Main Memory(Fast memory), this stores the information that are currently in processing and Auxiliary(slow memory), this stores the information that are current not in use.
TYPES OF COMPUTERS
1. Analogy Computers- processes the information in the form of continuous varying values, uses level of electrical quantity such as voltage to correspond to a numerical value to be measured. e.g. in Car's Fuel gauge, a float in the tank moves up and down altering electrical quantity accordingly. the resulting changes are transmitted electrically to the gauge on the dashboard.
2. Digital Computers- Operates on discrete (discontinuous) values known as Binary numbers(numbers that uses symbols 1 and 0(on and off) to represent information.
WHAT IS AN OPERATING SYSTEM?
An Operating System is a system software, consisting of programs and data, that runs on computer, manages computer hardware resources, and provides common services for execution of various application software.
System Software-is computer software designed to operate the computer hardware and to provide a platform for running application software.
Application Software-is computer software designed to help the user to perform singular or multiple related specific tasks.
INTRODUCTION TO PROGRAMMING.
WHAT IS PROGRAMMING
Is the process of giving instruction to a computer so as to execute a desired task.
Programming concept.
A Computer can not understand the normal human language, so a specific Computer programming language have been designed so as to link and simplify communication between the Programmer(User) and the Excuter(Computer). Programming languages fall into two categories.
Low level Languages-is a programming language that provides little or no abstraction from a computer's instruction set architecture. Can be converted to a Machine language without the use of Compiler or Interpreter. e.g Assembly language
High level Languages-is a programming language with strong abstraction from the details of the computer. Easier to use and portable. e.g. Pascal, Java, C, PHP etc.
Upon reading The above Introduction to Computers and Programming, you are now ready to proceed with the next lesson in PROGRAMMING IN PASCAL.
