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COMPUTER SOFTWARE EDIT Module 1: Introduction to Information Technology Think of a computer as a robot. What do you want it to do? We Want a Computer To: 1. Read input data from source documents or secondary storage. 2. Process the data. 3. Display the results. 4. Print the results. 5. Store the results. 6. Transmit the results. 7. Protect itself and the data. 8. Keep track of things that it is doing to restart. 9. Count things to reflect performance. 10. Do multiple things at the same time. For the computer to be able to perform all these requires the user to instruct the computer software to control the machine Why is this topic important Hardware is the engine and software is the gas that makes it run. To understand software concepts is to understand how real work gets done on computer-based systems within a business. To understand software is to appreciate the specific details that must be addressed for a new computer-based application to be implemented. Important Topics Major categories of software. The importance of operating systems and related systems software. The increasing importance of application packages. Challenges to implement application packages. The evolution of programming languages and the reason for so many languages. Computer Software The detailed instructions that control the operation of a computer system. Provide tools to people. Intermediary between people and data. Manage the computer resources. Selecting appropriate software for an enterprise is a key management decision. Overview of Computer Software Computer Software Application System Software Software General- Application- System System Purpose Specific Management Development Programs Programs Programs Programs Trends in Computer Software First Second Third Fourth Fifth Generation Generation Generation Generation Generation Trend: Toward Easy-to-Use Multipurpose Network-Enabled Application Packages for Productivity and Collaboration Natural & Object-Oriented DBMS Languages User-Written Packaged Operating Fourth- Multipurpose Programs Programs Systems Generation Graphic- Interface Machine Symbolic High-Level Languages Network-enabled Languages Languages Languages Microcomputer Expert-Assisted Packages Packages Trend: Toward Visual or Conversational Programming Languages and Tools Application Software: End User Applications 1) General Purpose Application Programs Software Suites – Microsoft Office – Word Processing - Word / Works / Claris – Spreadsheet – Excel / FoxPro / Lotus – Database Managers - Access / Dbase/Sybase Web Browsers – Internet Explorer / Netscape Electronic Mail – MS Outlook / Express / Eudora Presentation Graphics – Power Point / Flash Application Software: End User Applications 2) Application-Specific Programs Application Software Packages support managerial and operational uses: – Accounting – Transaction Processing – Customer Relationship Management – Electronic Commerce System Software: Computer System Management 1) System Management Programs • Operating System - Resource Management - File Management - Task Management • Network Management Programs • Database Management Systems • System Utilities System Software: Computer System Management 2) System Development Programs • Programming Language - BASIC / C++ / COBOL / JAVA/TURBO-PASCAL • Programming Translators - Assemblers – translates assembler language - Compilers – translates high level language [translate the program (source code) into machine code (object code), then execute the object code.] Programming Languages Machine Languages High Level Languages Markup Languages Use binary coded Use brief statements Use embedded instructions control codes 1001 1001 Compute X = Y + Z <H1>First heading</H> 1100 1101 <!ELEMENT Product (#Item | manuf)> Assembler Languages Fourth Generation Object-Oriented Use symbolic coded Languages Languages instructions Use natural statements Define objects that contain data and actions LOD Y SUM THE FOLLOWING NUMBERS Document.write ADD Z (“Hi There”) Operating Systems In short: – Five basic functions: » User interface » Resource Management Software » File Management – Application vs. System » Task Management Application Software » Utilities for support services – General purpose applications for end Programming users Languages System Software – Five major levels: » Machine language – Manage hardware, » Assembler language software, network, data » High-level language resources » Fourth-Generation » Object-Oriented Systems Software Definition: – All programs related to coordinating computer operations Components – Operating System – Utility programs – Program language translators Operating System Hidden Software Definition – provides access to all resources Kernel – Manages the operating system – Memory resident – Loads set of programs that lies between applications software and the hardware – Fundamental software that controls non-resident portions of the OS as needed Booting – Loads the kernel into memory Operating System A software program that acts as an intermediary between a user of a computer and the computer hardware. Exist because it is a reasonable way to solve the problem of creating a usable computer by better managing the computer resources. The basis for standardization of application software. (the platform) Functions of an Operating System User Interface Utilities Resource Task File (Data) and Other Management Management Management Functions Use of Managing the Managing Sort, Merge, hardware accomplishment Data and Performance, resources of tasks Program Files etc. Functions of OS Manage the computer’s resources – CPU – Memory – Disk drives – Printers Establish a user interface Execute and provide services for applications software Carries out all input and output operation Operating System Functions Multiprogramming - executing two or more programs concurrently using the same computer. Multiprocessing - executing two or more instructions simultaneously in a single computer by using multiple central processing units. Graphical User Interface (GUI) - part of the operating system that uses graphic icons to issue commands and make selections. User Interface Facilitates communication between the user and the operating system Two forms – Command line » Text-based » Key commands » Examples: MS-DOS, Unix – Graphical user interface (GUI) » Visual images » Menus » Examples: Windows, Mac OS, Linux Popular Operating Systems • DOS UNIX • Windows .X Linux OS/2 • Windows NT Mac OS IBM MVS, VM OS is Hidden User interested in application software to make the PC useful Application software is platform specific User must be aware of the type of OS User should be aware of the functions of OS What is the platform of your system? A common question posed to a system vendor, manufacturer or even the organization utilizing the system….. Platform Definition: Computer hardware and operating system software that dictate what other software can run E.g. Wintel Intel-based PC running on Microsoft Windows Types of OS Command line Single user PC Network Operating System (NOS) Command-line: MS-DOS Command-line interface Prompt – system is waiting for you to do something Key a command Not user-friendly Single-user PC: Microsoft Windows Graphical user interface Eases access to the OS Most new computers come with Windows already installed Network Operating System NOS Designed to permit computers on a network to share resources Examples – Windows 2000 Server – Novell Net Ware Provides – Data security – Troubleshooting – Administrative control NOS Functions Split between client and server computers Server – File management Client – Requests to the server – Messaging – Has own local OS Makes the resources appear as if they are local to the client’s computer Early Days of Windows OS Operating environment for MS-DOS Shell – layer added between users and DOS Windows Today Home/consumer market – Windows 95 – Windows 98 – Windows Millennium Edition (ME) Corporate market – Windows NT – Windows 2000 Windows XP Pocket computers and Internet appliances – Windows CE What are the prominent features of Windows? Prominent feature of Windows: GUI On-screen pictures – Icons – Menus » Pull down » Pop up – Click to activate a command or function Fast Easy Intuitive Windows 95 and 98 Self-contained OS DOS commands still available Start programs by – Start button – Double clicking the icon Task bar permits movement between open programs Long file names up to 255 characters Plug and play Object linking and embedding (OLE) Windows 98 Additions Internet / intranet browsing Support for DVD and additional multimedia components Support for large hard drives TV viewer and broadcast ability Wizards / Help Assistant Improved Windows Features Backup Interfaces with other software Networking features Security Dr. Watson Windows Helps reduce the cost of owning and maintaining a PC Windows ME Millennium Edition Multimedia support -- Windows Media Player 7 Jukebox – Record music CDs as digital files Windows Movie Maker – Basic video editing Windows Image Acquisition – Scanner and digital camera Windows ME Millennium Edition Reliability Features – System File Protection – AutoUpdate – System Restore Help Center Home Network Support – Wizard for connecting multiple computers and peripherals – Multiple users can share a single Internet connection Windows NT New Technology Engineered for stability Strong security Versions – NT Workstation – NT Server Drawbacks – Lacks support for older Windows and MS-DOS software and hardware – Complex to learn and use – Requires more memory and processing power Windows 2000 Stability features Security features Uses simple approach to hardware setup from Windows 98 Versions – Windows 2000 Professional for individual users – Windows 2000 for network servers Was intended for both the corporate and home use, replacing Win NT and Win 98 Windows 2000 Complex Heavy demand for computer resources Improvements over windows NT – Maintains user preferences – Self-healing applications software – Supports Windows 98 file structure – Uses plug and play – Provides improved support for laptops Windows XP Extends Windows ME and provides a more stable environment Two categories – Network server » 3 versions based upon network complexity – Desktop computer » 2 versions Professional Client Personal Client Windows CE Consumer Electronics Where used Embedded systems – Industrial controllers – Robots – Office equipment – Cameras – Telephones – Home entertainment devices – Automobile navigation systems Pocket PC Internet appliance market Windows CE Consumer Electronics Subset of Windows Less memory Smaller screens Little or no file storage Provides Internet connectivity Mac OS First commercially successful GUI (1984) Served as a model to other GUI systems UNIX Supports – Multi-user – Time-sharing Character-based system Command-line interface Runs on various processors and many types of computers Primary OS used on Internet servers LINUX UNIX-like OS Open-source software – Download it free – Make changes – Distribute copies – Restriction – any changes must be freely available to the public PC Setup – PC comes with Windows installed – Install LINUX in a dual-boot configuration LINUX Advantages over Windows – Extremely stable – Internet support – Reinstallation is simpler Disadvantage – Scarcity of applications Large Computers Used by many people at once OS works “behind the scenes” so users can share resources (hardware & software) OS must control – Who gets access to resources – What keeps the programs from different users from getting mixed up with one another Sharing Memory Program must be in memory to be executed Problems – Programs compete for space – May have a very large program – Memory space for each program must not overlap Memory Management The process of providing separate memory space to programs Memory Protection keeps one program from interfering with another Sharing Storage Several users need to access the same disk pack – One wants to write – Another wants to read OS keeps track of the I/O requests OS processes I/O requests in order received Utility Programs Come with System Software Handle special needs Perform secondary chores Do not need to be memory resident Functions of Utility programs File manager – provide access to lists of stored files Backup and Restore – make duplicate copies of important files and return the copy to the hard drive if needed File compression – reduces the amount of disk space required by a file Disk defragmenter – reorganize files so they are stored contiguously on disk providing for faster access Device drivers – convert operating system instructions into commands that are known to a specific device Are all operating systems the same? Features and functions. Advantages and benefits. From Personal Computers to Mainframes? Summary Operating systems are the foundation of a computer operation. Operating systems benefits include better resource utilization, better system performance, gains in cost- effectiveness and better overall management of the entire system. Without operating systems with advanced features and functions, computing would still be in its very early stages.
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