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Computer SoftwareComputer SoftwareCh.2-A,B,C; Ch.15-D,ECh.2-A,B,C; Ch.15-D,E

FALL 2000FALL 2000Rob WolfeRob Wolfe

DIT 2006 - Wolfe2

4 GoalGoal

Determine legal restrictions on SWDetermine legal restrictions on SW Describe the purpose of OSDescribe the purpose of OS Recognize DOS, Windows, UNIX, Mac Recognize DOS, Windows, UNIX, Mac

OSOS Categorize SW as either system or Categorize SW as either system or

applicationapplication Determine best SW for specific tasksDetermine best SW for specific tasks Recognize the 4 generations of Recognize the 4 generations of

Programming LanguagesProgramming Languages

DIT 2006 - Wolfe3

4 Computer ProgramsComputer Programs

A A computer programcomputer program is a set of is a set of instructions that tells a computer instructions that tells a computer how to carry out a task.how to carry out a task.

Computer programs are written in a Computer programs are written in a programming languageprogramming language that that computers can understand.computers can understand.

DIT 2006 - Wolfe4

4 Computer ProgramsComputer Programs

A sample programA sample program

program Conversion (input,output);

const inchesPerFoot = 12; centimetersPerInch = 2.54;var feet, inches, lengthInInches: integer; centimeters: real;begin write(‘What is the length in feet and inches?’); readln(feet,inches); lengthInInches :=inchesPerFoot * feet + inches; centimeters :=centimetersPerInch * lengthInInches; writeln(“The length in centimeters is’, centimeters:1:2)end

DIT 2006 - Wolfe5

4 Computer SoftwareComputer Software

SoftwareSoftware (as opposed to (as opposed to hardwarehardware) is ) is a set of statements or instructions to a set of statements or instructions to be used directly or indirectly in a be used directly or indirectly in a computer in order to bring about a computer in order to bring about a certain result.certain result.

Same as program? Data?Same as program? Data? SharewareShareware Public domainPublic domain

DIT 2006 - Wolfe6

4 Software LicenseSoftware License

Single-user license Single-user license — — limits use of limits use of software to one user at a timesoftware to one user at a time

Multiple-user license Multiple-user license — — allows more allows more than one user to use particular than one user to use particular softwaresoftware

Concurrent-user license Concurrent-user license — — allows a allows a certain number of software copies to certain number of software copies to be used at same timebe used at same time

Site license Site license — — allows software to be allows software to be used on all computers at specific used on all computers at specific locationlocation

DIT 2006 - Wolfe7

4 Classifying SoftwareClassifying Software

System SoftwareSystem SoftwareOperating SystemsDevice DriversUtilities

Application SoftwareApplication SoftwareMajority

Programming LanguagesProgramming LanguagesFour generations of programming

languagesVB Lab

DIT 2006 - Wolfe8

4 Software RelationshipsSoftware Relationships

ProgrammingLanguages

DIT 2006 - Wolfe9

4 Operating SystemsOperating Systems

Roles of OSRoles of OS I/O controlSystem resource allocationHardware failure detectionSecurity maintenance

OS examplesOS examplesUNIXDOSWindowsOS/2MAC OS

DIT 2006 - Wolfe10

4 Application SoftwareApplication Software

What is …What is …productivity software?A suite?groupware?

Before you graduate, make sure you Before you graduate, make sure you become very handy with …become very handy with …one word-processorone spreadsheet software packageone database management systemone presentation software package

DIT 2006 - Wolfe11

4 Application SoftwareApplication Software

Task-specific software, e.g.:Task-specific software, e.g.:Document productionGraphics - bitmap, vector, 3-D rendering,

animationPresentationNumeric analysisData managementConnectivityAccounting & FinanceVarious business software - Horizontal v.

Vertical

DIT 2006 - Wolfe12

4 Programming LanguagesProgramming Languages

Procedural Procedural v.v. Declarative Declarative Low-level Low-level v.v. High-level LanguagesHigh-level Languages Compilation Compilation v.v. InterpretationInterpretation

DIT 2006 - Wolfe13

4 Programming LanguagesProgramming Languages

Four GenerationsFour Generations1st generation 1940s, Machine Language2nd generation 1950s, Assembly

Language3rd generation 1960s, Proliferation4th generation 1970s, SQL

DIT 2006 - Wolfe14

4 First GenerationFirst Generation

1940s1940s Machine LanguageMachine Language CharacteristicsCharacteristics

Binary codeExtremely crypticTight coupling between machine and

programNot portable

DIT 2006 - Wolfe15

4 Second GenerationSecond Generation

1950s1950s Assembly LanguageAssembly Language CharacteristicsCharacteristics

A little less crypticStill strong coupling between HW and SWThus, not portableUp to this language is considered Low-

level

DIT 2006 - Wolfe16

4 Third GenerationThird Generation

1960s1960s Proliferation of LanguagesProliferation of Languages

BASIC, COBOL, Pascal, FORTRAN, C CharacteristicsCharacteristics

High-levelCompiling v. InterpretingStill dominantUp to this generation is procedural

DIT 2006 - Wolfe17

4 Fourth GenerationFourth Generation

1970s1970s SQL (Structured Query Language)SQL (Structured Query Language) CharacteristicsCharacteristics

Non-procedural, or DeclarativeSyntax is closer to natural languageMore powerful

DIT 2006 - Wolfe18

4 VB ProgrammingVB Programming

Structured ProgrammingStructured Programming Hierarchy ChartHierarchy Chart Sequence, Selection, IterationSequence, Selection, Iteration VB I.20VB I.20 (Problem #3) (Problem #3)

DIT 2006 - Wolfe19

4 In reviewIn review

Determine legal restrictions on SWDetermine legal restrictions on SW Describe the purpose of OSDescribe the purpose of OS Recognize DOS, Windows, UNIX, Mac Recognize DOS, Windows, UNIX, Mac

OSOS Categorize SW as either system or Categorize SW as either system or

applicationapplication Determine best SW for specific tasksDetermine best SW for specific tasks Recognize the 4 generations of Recognize the 4 generations of

Programming LanguagesProgramming Languages