1.1 - Introduction to Information Systems-1.pdf

INTRODUCTION TO INFORMATION SYSTEMS What is a Computer? A computer is a machine that is able to take information (input), do some work on or make changes to the information, to make new information (output).  Functions of the Computer These 4 functions are collectively called the Information Pro...

INTRODUCTION TO INFORMATION SYSTEMS What is a Computer? A computer is a machine that is able to take information (input), do some work on or make changes to the information, to make new information (output).  Functions of the Computer These 4 functions are collectively called the Information Processing Cycle: 1. Accepts data - INPUT 2. Processes data – PROCESS 3. Produces output – OUTPUT 4. Stores results – STORAGE Basic Components of the Computer System There are two basic components of the computer system:  Hardware  Software  Peopleware (User) Hardware  HARDWARE CONCEPTS  Digital device  works with discrete signals, such as 0 and 1  Analog device  works with continuous data  Digital data representation How can a computer represent numbers using bits? “0” and “1” are also known as bits or binary digits The computer uses the binary number system which uses only two digits: 0 and 1. A series of 0’s and 1’s results in a particular number much in the same way we use the decimal number system Digital Data representation Decimal (Base 10) Binary Base 2 0 0000 1 0001 2 0010 3 0011 4 0100 5 0101 6 0110 7 0111 8 1000 9 1001  Digital Data representation A closer look on bits:  How come 5 became 0101 when converted to binary?  BITS AND BYTES  BIT an abbreviation of binary digit Abbreviated as a lowercase “b”  BYTE a collectio1n of bits (8 bits) abbreviated as an uppercase “B”  DIGITAL ELECTRONICS  Basic parts of a computer Processor or CPU Input Output Devices Devices Computer Memory Hardware - refers to the physical part of the computer system. It includes all the physical objects that can be touched Computer hardware equipment is grouped into: 1. Input Device is any piece of computer hardware equipment used to provide data and control signals to the computer. Example: Mouse Keyboard Joystick Scanner Hardware 2. Output Device is any piece of computer hardware equipment used to communicate the results of data by converting them into human-readable form. Example: Speaker Monitor Printer Hardware 3. Storage Device is a technology consisting of computer components and stores data information. Example: Hard Disk Flash Disk Compact Disk (CD) Hardware 4. Processing Device is the device that processes the information by the computer processor (CPU), which performs data calculations, data comparisons, and data copying with the information. Example: Motherboard Central Processing Unit (CPU) Random Access Memory (RAM) Software Software - is also known as computer programs. It is a component of computer that cannot be touched. Computer software operates and gives instruction to the computer hardware. The two types of computer software are: 1. System Software or operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. Example: Windows was created and sold by the Microsoft Corporation which was founded by Bill Gates and Paul Allen. Software The Mac OS was originally named as the Macintosh on 1996. In the late 1984 the first name of the Macintosh was called “Systems” that was developed by the Apple Incorporation which was founded by Steve Jobs, Steve Wozniak, and Ronald Wayne. Linux operating system, assembled under the model of free and open source, is software developed and distributed by Linus Torvalds in 1991. Software 2. Application Software is all the computer software that causes a computer to perform useful tasks beyond the running of the computer itself. Applications may not work if there is no operating system installed. Example: Office Applications Games  SOFTWARE DEVELOPMENT LIFE CYCLE  Software Development Life Cycle  a methodology that is typically used to develop, maintain, and replace information systems for improving the quality of the software design and development process  Importance of SDLC  In order to create systems that are good in design  It serves as a guide in systems development  SOFTWARE DEVELOPMENT LIFE CYCLE Five phases of SDLC  Planning  Analysis  Design  Implementation  Maintenance SOFTWARE DEVELOPMENT LIFE CYCLE Planning Phase  the initial stage in the SDLC that has to be performed  includes the information about the requirements for the proposed software  known as the feasibility study phase “In the first phase of the SDLC, the organization’s total information system needs are identified, analyzed, prioritized, and arranged.” SOFTWARE DEVELOPMENT LIFE CYCLE Analysis Phase  requires the analyst to thoroughly study the current procedures or software used to execute tasks in an organization  the main goal in this phase is to identify the requirements for a new software or simply change several aspects in the current working system “This phase studies the current system and produces proposed alternatives or replacements.” SOFTWARE DEVELOPMENT LIFE CYCLE Design Phase  during this phase, the developer of the software translates the result of the previous phase into actual design or specifications of the software  development of the software involves covering the input and output screens to reports, databases, and computer process SOFTWARE DEVELOPMENT LIFE CYCLE Implementation Phase  Coding  creation of the actual program  Testing  both programmer and analyst submits the software to various “quality testing” to discover if there are any bugs within the software  Installation  after coding and testing is done, the actual software must be installed and slowly or completely replaces the old software SOFTWARE DEVELOPMENT LIFE CYCLE Maintenance Phase  used to make necessary patches to remove found errors  where the software is systematically repaired and improved based on errors or possible new requirements found  SOFTWARE DEVELOPMENT LIFE CYCLE Waterfall SDLC  Suggests that prior to proceeding to next phase, the current phase should be finished first. Peopleware Peopleware - refers to the role of people in the computing process. It also refer to many different things, including computer engineers, programmers, individual computer users, or groups of people. Without user interaction, most computers would be useless machines.