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Explore the concept of a computer, the Von Neumann Model, computer hardware and software, algorithms, computer languages, software engineering, and operating systems.
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What is computer? Computer: is a machine that accepts input data, processes the data and creates output data. This is a specific-purpose concept of computer
Today’s computer is general purpose machine “Programmable computer” • A program is a set of instructions that tells the computer what to do with data. • Early days, computer program used to be implemented by changing the wiring or turning a set of switches on and off. Today, a program written in computer language
In programmable computers, the output data depend on: 1. The Input data
Von Neumann Model • Named after John von Neumann • Von Neumann Model consists of: • Memory: storage area, where programs are stored during processing. • Arithmetic Logic Unit (ALU): where calculations and logic operations take place. • Control Unit: Controls the operation of memory, ALU and input/output subsystems. • Input/Output: Input units accept input data(e.g. keyboard….). While output units demonstrate output data ( monitor….)
Stored Program Concept • Von Neumann model states that program must be stored in memory unlike early computer where only data are stored. Sequential Execution of Instructions • Control Unit executes the set of a program’s instructions one after another (sequentially) Computer Hardware • Computer Hardware Must include all four parts of von Neumann Model
Data Storage and Organization • Data storage: • Data stored as electrical signal. • Computer stores data in Binary form (0,1). • All sort of input data must be transferred into binary data. • Organizing Data: • Data are organized into small units, small units are organized in larger units.
Computer software According to Von Neumann Model: • Program must be stored in the memory. • Program must be a sequence of instructions • Program is made of instructions • Instructional format of programming support “reusability” of programming in different platforms.
Algorithms • In order to structure a program to solve a specific problem, computer programmer must break down the program into steps, each step is an instruction, those step-by-step solution is called algorithms Language • Computer language is (in concept) similar to human language, though very limited. • Computer language is made of set of symbols each symbol represents an instruction.
Software Engineering • Is the design of structured programs following strict principles and rules of programming languages. Operating Systems • Works as an interface between computer program and computer componants.
