Chapter 1 - PPT PDF

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Chapter 1 Overview of Computers & Programming Computer: A programmable machine that can store, process and retrieve data.

Computer Components 1. Central Processing Unit (CPU) The brain of the computer and consists of arithmetic/logic unit (ALU) & Control Unit (CU).  ALU: Responsible for performing arithmetic operations (additions, subtraction, division, etc) and logical operations (greater than, equal to, less than, etc).  CU: Decodes each machine instruction and sends signals to the other components telling them what operations to perform in order to carry out the instruction. By decoding we mean translating the retrieved instruction into a series of computer commands.

2. Memory A collection of numbered cells for storing instructions and data. The following is an example of a memory cell:

Address 00000101

Content 01000001

All data stored in memory are represented digitally using binary (base 2) numbers composed of zero and one digits. These binary digits are also called bits. A byte of data, typically 8 bits, is the amount of memory required to represent a single character. The character in the above cell is represented as 1x2 0 + 0x2 1 +0x2 2 +0x2 3 +0x2 4 +0x2 5 +1x2 6 +0x2 7 = 65 which is the code commonly used for the letter A. The meaning of a memory cell value is determined entirely by how the computer uses it. A memory cell can store a numeric value, a character, and a picture element of an image.

3. Input/Output Devices Devices that perform transformations to enable humans to communicate with digital computers. Common input devices include keyboard and mouse and common output devices include monitors and printers.

4. Secondary Storage 1

Storage devices that retain data during a power loss or when the computer is turned off. The most common secondary storage devices today are Compact Disks (CDs) which can hold up to 737 MB, Digital Video Disks (DVDs) which can hold up to 17 GB of data, and Flash Sticks which can store up to 128 GB of data.

Computer Software The previous sections described the computer hardware which is the physical components of a computer system. Computer software, on the other hand, refers to all computer programs that are used to perform different functions. Such programs are classified into three categories:

1. Operating System (OS) The collection of computer programs that is used to manage the computer hardware. OSs are classified into two categories:  Command-Line Interface OSs: Such OSs have a prompt that accepts and processes user commands. Examples of such OSs are DOS, UNIX, OS/2 and VMS.  Graphical User Interface OSs: Such OSs have a Graphical User Interface (GUI) that the user can interact with to perform functions. A common GUI OS is the Microsoft Windows OS.

2. Application Software Computer programs that perform specific tasks. For example, MS Word is a word processing software application used to create documents. MS Excel is another software application used to create spreadsheet documents.

3. Computer Languages   

Machine Language: Collection of binary numbers. Assembly Language: a language in which computer operations are represented by mnemonic codes that correspond to machine language instructions. High Level Programming Languages: Languages that use English-Like statements to give instructions to computer to perform specific tasks and a compiler is used to translate these English-Like statements into machine language instructions. The following table lists some of the common programming languages and their application areas:

Language

Application Area

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FORTRAN COBOL, C, BASIC Lisp Prolog Ada Visual Basic C++ Java

Scientific Programming Business Data Processing Artificial Intelligence Artificial Intelligence Real-time distributed systems Graphical User Interfaces Object-Oriented Programming Object-Oriented Programming, Web Programming

Integrated Development Environment (IDE) An integrated development environment (IDE) is a set of tools for software development which commonly combine: a text editor, compiler, linker, debugging tools and loader. In this course, we will use an IDE called Microsoft Visual Studio which supports many programming languages including C++ which we will use in this course. Figure 1 below illustrates the different tools of IDE and the function of each tool.

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Figure 1: Entering, Translating, and Running a High-Level Language Program

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