Chapter 3

Module 3ASystem Software Module 3BProgramming Languages 3 System Software and Software Development

3 System Software l Operating Systems (OS): The Computer’s Traffic Cop l Exploring Popular Operating Systems: A Guided Tour l System Utilities: Tools for Housekeeping Module A

3 Operating Systems The OS is much like a computerized version of a traffic cop, standing at the intersection of the computer’s hardware, application programs, and the user. System Software Module A l kernal/supervising program ämemory resident

3 Operating Systems l Managing Programs äsingle-tasking ämultitasking äforeground application äbackground application ämultiprocessing System Software Module A

3 Operating Systems System Software Module A The OS manages programs, parcels out memory, deals with input and output devices, and provides means of interacting with the user

3 Operating Systems l Managing Memory äpartition ävirtual memory äswap file l Handling Input and Output ädevice drivers System Software Module A

3 User Interface l Types of User Interface äcommand-line ämenu driven ägraphical user interface (GUIs) l User Interface functions ägain access (log on) ästart (launch) ämanage disks and files äshut down safely System Software Module A

3 Exploring Popular OS l Unix l Xerox PARC & the first GUI l MS-DOS l Mac OS l Microsoft Windows 3.x Module A System Software

3 Exploring Popular OS l Microsoft Windows 95 and 98 l Microsoft Windows CE l Microsoft Windows NT l Linux Module A System Software For the latest on Linux, visit Linux online visit Linux online

3 System Utilities: Tools for Housekeeping l Backup utilities l Antivirus software l File compression utilities l File defragmentation programs Module A System Software

3 Antivirus Software System Software Module A Norton AntiVirus is a utility that works by examining all the files on a disk, looking for the tell-tale "signatures" of virus code

3 Programming Languages l First Generation : 1s and 0s l Second Generation: A little Easier l Third Generation: Programming Comes of Age l Fourth Generation: Getting away from Procedure l Object Oriented: A Revolution in the Making? l A Guide to Programming Languages: One Size doesn’t Fit All Module B

3 Programming Languages l First Generation ämachine language: 1s and 0s ämachine dependent l Second Generation äassembly language älow-level ämnemonics Programming Languages Module B

3 Third-Generation Languages (3GL) l Description äProcedural ähigh-level l Compilers äsource code/object code älow-level l Interpreters Programming Languages Module B

3 Third-Generation Languages (3GL) l Spaghetti Code äsoftware crisis l Structure Programming äPascal/Algol älow-level l Modular Programming Programming Languages Module B

3 Fourth-Generation Languages (4GL) l report generators l query languages äStructured Query Language (SQL) l natural language Programming Languages Module B

3 Object-Oriented Programming: A revolution in the making l Eliminating the program vs data distinction l What is an object? l Classes l Inheritance l Rapid Application Development (RAD) l Middleware Programming Languages Module B

3 A Guide to Programming Languages l COBOL äbusiness programming äY2K l Fortran äscientific/mathematical/engineering ägood for complex problems Programming Languages Module B Learn more about COBOL by reading the FAQ located on the Oxford University Library Automation ServiceOxford University Library Automation Service

3 Structured & Modular Languages l Ada l Visual Basic äevent-driven äVbscript äActiveX controls l Pascal Programming Languages Module B

3 Object Oriented Languages l Smalltalk l C and C++ Programming Languages Module B A simple C++ program that prints Hello World to the screen If you’re thinking about a career in computer science, C++ is the language to learn. For more information see the C++ Virtual Library and C++ FAQ Litethe C++ Virtual LibraryC++ FAQ Lite # include void main () { cout <<“Hello World!”;

3 Object Oriented Languages l Java l JavaScript Programming Languages Module B Simple Java code To learn more about Java, visit Java’s home page at Sun MicrosystemsJava’s home page at Sun Microsystems class Hello World { public static void main (String args { } ) { System.out.println (“Hello World!”) }