1 Computer software Overview **** 2 Computer software: overview of various types Computer (disk) operating system(s) User interface program(s) Utility

1

Computer software

Overview

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2

Computer software:overview of various types

• Computer (disk) operating system(s)

• User interface program(s)

• Utility package(s)

• Local area network software

• Application software package(s)

• Training package(s)

• Data: clipart, sounds, video,...

• Documentation / manual(s) / README files

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Computer software:between user and computer

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O perating system:Process management M emory management

F ile Input/O utput D evice Input/O utput

C om puter periphera ls

C om puter

D evice drivers

O perating system shell Application software

U ser

4

Computer software

Computer (disk) operating systems

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5

!? Question !? Task !? Problem !?

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List and discuss widespread computer operating systems.

List and discuss widespread computer operating systems.

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Computer operating systems for microcomputers

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• For microcomputers with Intel compatible CPU

»DOS; DOS + Windows 3.x; Windows 95; Windows 98; Windows 98 SE; Windows ME,…

»(OS/2)

»Windows NT 4 Workstation; Windows 2000 Professional,...

»Linux,…

• Apple operating systems

7

Computer operating systems for server computers

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»Unix (and variants such as Linux)

»Windows NT 4 Server; Windows 2000 server versions;...

8

Computer operating systems: properties

Operating system

Multi-user?

Multitasking?

Long descriptive file names?

Unix DOS DOS + OS/2 Windows NTLinux Windows 3.x Windows 95 Windows 2000

Windows 98 + - - - +

+ - - + +

+ - - + +

**--

9


**--

Why can multitasking on computers be useful?

(even though people mostly work on 1 activity at the same time)

Why can multitasking on computers be useful?

(even though people mostly work on 1 activity at the same time)

10

Multitasking: uses

• Switching among programs

the ability to load several programs and easily and quickly switch among them

• Running tasks in the background

for instance:

»downloading data,

»printing,

»monitoring disk space,

»receiving electronic mail,...

***-

11


**--

Unix and Linuxhave many positive properties,

but have not been used on most microcomputers.

Why?

Unix and Linuxhave many positive properties,

but have not been used on most microcomputers.

Why?

12

Computer operating systems: Unix:problems and drawbacks (Part 1)

**--

The code requires more disk space than most operating systems developed for small personal computers up to 2000.

The system is suited for more multiple users on the same computer, and therefore it is more complex than most operating systems developed for small, single-user personal computers.

13

Computer operating systems: Unix:problems and drawbacks (Part 2)

**--

Does not support as many microcomputers hardware devices and commercial applications as Microsoft Windows.

The many versions and interfaces may confuse users.

14

Computer operating systems: Unix:character-based interface commands

*---Example

•cat

•cd

•cp

•ls -la

•man

•mkdir

•more

•mv

•rm rmdir

Views the contents of text files

Changes directory

Copies files

Lists files

Accesses the reference manual online

Makes a new directory

Displays a text file, 1 page at the time

Moves or renames files

Removes a file Removes a directory

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**--

Windows NT4 and Windows 2000have many positive properties,

but are not used on most low-end PC’s.Why?

Windows NT4 and Windows 2000have many positive properties,

but are not used on most low-end PC’s.Why?

16

Computer operating systems: DOS:character-based interface commands

*---Example

•cd

•copy xcopy

•dir

•Mkdir, md

•rename

•rm del

•rmdir

Changes directory

Copies files

Lists files

Makes a new directory

Renames files

Removes a file

Removes a directory

17

User interface software for DOS: some character-based packages

• DOSShell

• PCTools / PCShell

• Norton Commander

• Desqview

• ...

*---

18

User interface software for DOS: some graphics-based packages (GUIs)

• DOSShell

• Microsoft Windows 1, 2, 3.x

• Norton Desktop for Windows

• ...

*---

19

Computer operating systems: evolution

• More user-friendly interfaces

• Increasing power

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20

Computer software

Graphical user interface = GUI

**--

21

Graphical user interface = GUI: description

The interface on the display is built up using individual picture elements (= pixels) in an array.

Suitable for the application of WIMP techniques:

Windows,

informative Icons,

a Mouse or another pointing device 8,

Pull-down menus / Pointing

**--

22

Graphical user interfaces: examples

Operating system

Apple Macintosh

Unix

DOS + Windows

Windows 95

OS /2

Windows NT 4

Windows 98

Windows 2000

Graphical user interface

Macintosh System

Open Look, OSF / Motif

Microsoft Windows 1, 2, 3.x

Windows 95

Presentation Manager

similar to Windows 95

Windows 98

Windows 2000

**--Examples

23


**--

Which benefits offer GUIs ?(in contrast with

character-based interfaces)

Which benefits offer GUIs ?(in contrast with

character-based interfaces)

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Graphical user interfaces: benefits (Part 1)

The display can offer better WYSIWYG: What You See (on the display) Is What You Get (on printed paper)

The user can change the size of windows on the information continuously.

The user can choose and use various types and sizes of characters in the user interface.

**--

25

Graphical user interfaces: benefits (Part 2)

The user can address every single pixel (using a pointing device such as a mouse) to generate an action by the computer.

The computer can create detailed icons.

...

**--

26


**--

Which disadvantage have GUIs?

Which disadvantage have GUIs?

27


**--

How can WYSIWYG work well?

Why did earlier systems not offer WYSIWYG as well?

How can WYSIWYG work well?

Why did earlier systems not offer WYSIWYG as well?

28

Graphical user interfaces: disadvantage

Requires a relatively fast computer system:

»fast processor,

»fast video,

»fast hard disk,

»caching hard- and software,

»...

**--

29


**--

What is easier to do with a mouse

than with a keyboard?

What is easier to do with a mouse

than with a keyboard?

30

Mouse is complementary to the keyboard

• Drag to change size and/or shape of objects (windows, graphics, ...)

• Point and click to activate

• Drag and drop:

»Make selection, drag selection, and paste or put elsewhere

»Select a document by it’s name or icon, drag it to the program’s name or icon, release the button to make the program work with the document

»Free-hand drawing

**--

31

Computer software

Microsoft Windows: an operating environment

**--

32

Microsoft Windows: an operating environment

Application programs + Utility programs

Layers for Windows 1.x, 2.x, 3.x:

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33

Microsoft Windows: benefits with all applications (Part 1)

Offers a graphical user interface for DOS (“shell”).

Allows multi-tasking of programs.

The Windows package includes utility programs.

Due to the multi-tasking, utility programs provided by Windows can be used by application programs, so that each application program does not have to offer these utilities.

**--

34


The Windows package includes basic application programs for

» text editing,

»word processing,

»communications,

»file management,

»calculations,

»bitmap editing,

» ...

**--

35


Allows cut , copy and paste of data

»in the same document managed by the same program!

»between various documents managed by the same program!!

»between various documents managed by various programs!!!

**--

36

Microsoft Windows (all versions): benefits with Windows applications

Interface is more uniform, consistent, standardised.

Saves time during installation of programs + saves space on the hard disk, by providing “drivers” for output to video display(s), printer(s), sound board(s),... which can be used by all programs for Windows.

Allows software development which is more independent of display hardware.

DDE / Dynamic Data Exchange among documents

**--

37

Microsoft Windows from version 3: benefits with Windows applications

OLE / Object Linking and Embedding

Provides access to more than 640 K RAM, starting from version 3.0.

Provides TrueType technology for output to video display and printer, starting from version 3.1.

Allows drag and drop of files to the icons representing application programs.

**--

38

Success of Microsoft Windows

“Horizontal” = multi-purpose software inexpensive

many millions of copies of this package have already been distributed internationally.

**--

39

Microsoft Windows tutorials

• Computer-assisted learning about Windows is offered by the Windows package itself.

• Web-based learning about the basics of personal computers and about using Windows is available free of charge from http://www.nassets.com/bb/

***-

http://www.nassets.com/bb/

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Evolution of Microsoft operating systems for PC’s

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1981 DOS 1

1985 DOS + Windows 1.0



1995 Windows 95

1996

1997 Windows 95 + upgrades Windows NT 4 Workstation

1998 Windows 98

1999 Windows 98 SE

2000 Windows ME Windows 2000 Professional

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Computer software

Utility software packages

**--

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Utility software packages: definition

• Not a well defined term

• One meaning is:Software which helps to run the computer system,but which is not directly useful on the application level.

• Operating systems include utility programs;others can be installed besides these or can replace these.

**--

43

Utility software packages: categories

• Anti-virus scanning and shielding

• Compression / decompression of files

• Archiving / de-archiving of files

• Encoding / decoding of files

• Monitoring CPU-use, disk-space left, disk reading and writing, battery power in the case of portable computers,...

• ...

**--

44

Computer software

Local Area Network software packages

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45

LAN software packages for homogeneous networks: examples

• Intel compatible processors:

»LANtastic,

»Novell,

»Windows for Workgroups, Windows 95, Windows 98, Windows 2000,...

» ...

• Apple, ...

**--Examples

46

LAN software packages for heterogeneous networks: examples

Based on TCP/IP (protocol suite used in Internet)

• For DOS:

NCSA (= National Center for Supercomputing Applications) CUTCP, PC/NFS,...

• For Windows 3.x:

PC/NFS, PC/TCP, Trumpet TCP Manager,...

• For Windows 95, 98,...: included!

• For Windows NT, 2000,...: included!

****Examples

47


****

Which basic network software can you use in your institute?

Which basic network software can you use in your institute?

48

Computer software

Application software packages

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Categories of application software packages

• Text editing...Word processing...Desktop publishing

• Spreadsheet

• Presentation creation

• Graphics (bitmap/pixels and vector/object or mixed)

• Multimedia authoring + distribution

• Data communications (basic layers + applications)

• Portable document software

• Database management systems

• ...

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50

Software for text editing: categories

• Simple text editors

• Simple word processing software

• Powerful word processing software

• Page-layout software / Desktop publishing software

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51

Software for word processing: examples

• For DOS

»Microsoft Word (Microsoft)

»WordPerfect

• For Windows

»Microsoft Word for Windows (Microsoft)

»WordPerfect for Windows (Corel)

»Word (Lotus-IBM)

**--Examples

52

Software for word processing: screen shot

**--Example

53

Design of documents on paper: a brief checklist (Part 1)

• Is the general appearance attractive (not messy)?

• Does the text look well (not squashed up)?

• Do the pages have a basic shape?

• Is there adequate white space?

• Is the line length short enough?

• Are letters in CAPITALS avoided?

• Is underlining of letters avoided?

• Are fonts chosen well?

• Is the character size OK?

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• Is the typography consistent throughout the document?

• Are colours used well?

• Are illustrations/graphics/pictures used well?

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• Is it easy to see the main points?

• Are there a sufficient number of chapter and sub-chapter headings?

• Are the headings informative?

• Is the number of heading levels not too high?

• Are the differences in heading levels well supported by differences in formatting of chapter numbers and characters?

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56


Create a document with chapters, using heading styles.

Create a document with chapters, using heading styles.

***-

57


Create a document with chapters, using heading styles,and apply outlining.

Create a document with chapters, using heading styles,and apply outlining.

***-

58


Create a document with chapters, using heading styles,

and create a table of contents on 1 page,using styles.

Create a document with chapters, using heading styles,

and create a table of contents on 1 page,using styles.

***-

59


What are the benefits of using styles

in word processing?

What are the benefits of using styles

in word processing?

***-

60

Software for word processing as adatabase system: tools

• Styles for paragraphs (for instance Heading level 1, 2, 3,…)

• Outline view (hiding levels low in the hierarchy)

• Tables with rows and columns

• Sorting

+ combinations of these

***-

61

Software for word processing as adatabase system: input methods (1)

• Each (small) database can correspond

»with a whole document created with a program for word processing OR

»with a chapter of a document created with a program for word processing; then outlining can be used to view and select these chapters.

***-

62

Software for word processing as adatabase system: input methods (2)

• Methods to work with database records and fields in records:

»Using a table OR

»Using paragraphs formatted with styles

***-

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Software for word processing as adatabase system: using a table

• Methods to work with records and fields:

»Each record in one row

»Each field of each record in a column. (This allows sorting of the records based on the content of a selected field.)

***-

64


Build a table and sort the rows (records / items),

based on the contents of the columns (fields).

Build a table and sort the rows (records / items),

based on the contents of the columns (fields).

***-

65

Software for word processing as adatabase system: using paragraphs

• Using paragraphs formatted with styles

»Each record consists of several paragraphs.

»Each field corresponds to one of these paragraphs. (This allows sorting the records based on the first field, by using heading styles and outlining.)

***-

66


Use heading styles to create a small structured list,

such as a directory or bibliography.

Use outline view to look at this list.

Sort some records, using outline view.

Use heading styles to create a small structured list,

such as a directory or bibliography.

Use outline view to look at this list.

Sort some records, using outline view.

***-

67

Software for word processing as adatabase system: retrieval features

• Searching / retrieval / queries can be made

»By sequential string searching (fast enough with a fast computer and a small database)(can be slow with a slow computer or a large database)

»Retrieval of record after record; no selection of a record set

»No Boolean retrieval; no positional operators

***-

68


Test the speed of string searching with the hard- and software

that you use to store information.

Test the speed of string searching with the hard- and software

that you use to store information.

***-

69

Software for word processing as adatabase system: output features

• No sorting or relevance ranking of selected records in output.Databases perform better in this area.

• When records consist of several paragraphs together

»using styles for paragraphs allows efficient formatting of fields in such records

»outlining allows to output only the first parts of records

***-

70


Prepare a printout on 1 sheet of a table with visible borders, and 4 cells, that contain

1) an image of an animal, 2) the name of that animal,

3) your name,4) a very brief description of the origin of the animal file

(To avoid that everyone does the same work: the name of the animal should start with the same character as your family name.)

Prepare a printout on 1 sheet of a table with visible borders, and 4 cells, that contain

1) an image of an animal, 2) the name of that animal,

3) your name,4) a very brief description of the origin of the animal file

(To avoid that everyone does the same work: the name of the animal should start with the same character as your family name.)

**--

71

Spreadsheet software packages: examples

• For DOS (without Windows):

»Lotus 1 2 3

»Quattro

» ...

• For Windows:

»Lotus 1 2 3

»Quattro

»Excel

» ...

**--Examples

72

Spreadsheet software packages: screen shot

*---Example*

73

Program typesthat handle graphics

• Word processing programs...Lay-out programs

• Presentation programs

• Portable document software

• ...

• Bitmap / pixel oriented editing programs

• Vector graphics / object oriented programs

• Hybrids of the above

• ...

**--

74


**--

Why are bitmaps not ideal for the storage and distribution

of formatted documents?

Why are bitmaps not ideal for the storage and distribution

of formatted documents?

75

Portable document software: What is it? (Part 1)

Ideally, this type of programs

• allows the distribution of a formatted document, while maintaining the visual integrity of the document

• is independent of computer platform, (computer, operating system, application software, or fonts) that is used

»to create the document, and

»to view (read, search, ...) the document

• compresses the document

**--

76

Portable document software: What is it? (Part 2)

• allows printing the document

• allows searching for character strings in the document

• allows zooming in, without loss of details in the characters

• allows copying text fragments

• allows integration with a WWW browser

• allows hyperlinks / WWW links in the document

• ...

**--

77

Portable document software: applications

• On-line help documents coming with software.

• Electronic publications on CD-ROM and on-line, in particular when a version printed on paper also exists!

**--

78

Portable document software: some programs

• Adobe Acrobat !»Viewer software is available free of charge

»Software to create PDF files is NOT free of charge; a free trial is possible through the WWW

• Catchword RealPage

**--Examples

79


**--

Display an existing PDF document;apply searching for text;

zoom in.

Display an existing PDF document;apply searching for text;

zoom in.

80


**--

Which disadvantages of PDF do you see (in comparison with other document file formats)?

Which disadvantages of PDF do you see (in comparison with other document file formats)?

81

Software for multimedia authoring + distribution: some programs

• Authorware

• Iconauthor

• Guide

• Multimedia Toolbook

• Multimedia Viewer

• Tour Guide

• …

+ programs for web development

*---Examples

82

Software for database management: overlapping categories

• Relational

• Object-oriented

• Text-oriented

• Graphics-oriented

• ...

**--

83


**--

Which programs do you know that can quickly offer an overview

of pictures stored on a pc?

Which programs do you know that can quickly offer an overview

of pictures stored on a pc?

84

• ACDSee

• Paint Shop Pro

• Thumbs Plus

• ...

**--Examples

Shareware

Shareware

Shareware

Software for image database management: some programs

85

Speech recognition software: functions

• Recognition and transfer of spoken commands to other programs.

• Recognition of spoken text to create documents.

**--

86

Speech recognition software

**--

Ariadne / Campbell

87

Computer software

General evaluation criteria in the case of software packages

**--

88


**--

Which general factors should you consider

in the evaluation / selection of any software package?

Which general factors should you consider

in the evaluation / selection of any software package?

89

General evaluation criteria in the case of software packages (Part 1)

• Which operating system is required by the application software?

• How good and reliable is the software producer: its history, reputation, future,…?How good and reliable is the software supplier / distributor / dealer?

• How many installations and users are there

» in the country?

» in the region?

» in the world?

**--

90


• To which extent is the software compatible with hardware that is already available (such as computers, displays, printers…)?

• To which extent does the software require new hardware?

• Does the software allow an efficient usage of a mouse?

• Is the software package easy to use? Ergonomic aspects are important, as training of personnel is expensive and time consuming.

**--

91


• Does the program use random access memory and other computer system resources efficiently?

• Are good and up to date manual(s) for the package available?Is an online tutorial (computer-based training) available?

Does the software provide online help? (in context?)

**--

92


• Is good training and support available in your area, from the producer directly, or from the distributor, or from others…?

At what price?

• Is communication with other users easily available for discussions and to solve problems? Online? Through the Internet?

• What is the initial price per user, per site…?

• Are regular and substantial updates available? Online or only offline? At what price?

**--

93


• Can the user program extensions?

• When some computer system is already used, can existing, available data be exported from that system and can they be imported to be managed by the new system?

**--

94


• Is using an ASP (Application Service Provider) / networking / co-operation / … considered as an alternative for in-house implementation and development of computer software? Examples: computer networks for libraries; electronic mail through the WWW;…

**--

95


• How well can data be exchanged with other persons, institutes, computer systems, databases:

»import of data? Example: downloading of database records from an available database/catalogue of books, compact disks, films, videos…

»export of data? Example: contributing database records to a union catalogue of journals, books…

**--

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• Is the software compatible with standards used in data input, import from other systems, export to other systems,…Examples: availability in the case of software for a database system of a thesaurus module with standard relations among thesaurus terms; book database record formatting according to Unimarc for export to another database; import and export of HTML files used on a web…

**--

97


• Is the software suitable for use in an Internet context?Examples: create or export files in HTML format to make them available through the WWW or an intranet; the creation of e-mail messages by the software to alert users of problems, things to do…

**--

98

Computer software

Introduction to file formats

***-

99

The relations between programs and file formats

Programs to edit/create/develop/maintain a file in a particular format

File stored in a particular format

Programs to read/view files in a particular format

+ Programs to save=convert=export files from one format to another

***-

100

The program functions editing, viewing, converting

A program can incorporate only 1, 2, or all 3 of the functions

• Editing / creating

• Reading / viewing / interpreting

• Converting / saving / exporting for particular file formats.

***-

101

Examples of programs for editing, viewing, converting

Examples:

• Microsoft Word can create/edit + view/read + convert the file in the formats DOC, RTF, HTML.

• Adobe Acrobat Reader can only view / read (but not create/edit or convert/save) files in PDF format.

***-Examples

102

Computer software

File formats for text only

***-

103

File formats for text only: examples

Type

• Files containing unformatted ASCII text

• Files with text coded by the Hypertext Markup Language

Normal file name extension

.TXT

.HTML or .HTM

***-

104


**--

Why can HTML files be considered as text only, even when many web pages made with HTML

contain graphics/images/photos?

Why can HTML files be considered as text only, even when many web pages made with HTML

contain graphics/images/photos?

105

Computer software

File formats for graphics/images

***-

106


**--

Explain the differences between bitmap graphics

with vector graphics.

Explain the differences between bitmap graphics

with vector graphics.

107

Graphics formats: bitmaps and vector graphics

**--

• Bitmap graphics used in programs for “painting”

• Vector-based graphics used in programs for “drawing”

108


**--

Draw a small circle with a paint program for bitmaps and save this.

Draw a small circle with a draw program for vector graphics and save this.

Select each drawing and enlarge it.

What is the difference between the resulting drawings?

Draw a small circle with a paint program for bitmaps and save this.

Draw a small circle with a draw program for vector graphics and save this.

Select each drawing and enlarge it.

What is the difference between the resulting drawings?

109

Graphics formats: bitmaps compared with vector graphics

**--

Bitmaps

+

-

large

Vector graphics

-

+

small

Property

•Suited for “painting” and “retouching”

•Resolution adapted to output medium

•Size of files

110

Graphics formats for bitmaps only

File name extension

BMPGIFJPGPCX, PCCPNGRLETIF...

Origin

MicrosoftCompuServe / UnisysJPEGZ-Soft PaintbrushW3C

Aldus PageMaker...

***-Examples

Maximum number of colours

maximum 256 coloursmore than 256 colours

more than 256 colours

111


**--

Which properties of graphics file formats for bitmap images are important?

Which properties of graphics file formats for bitmap images are important?

112

Graphics formats for bitmap images: a comparison

• Maximum number of colours in one image?

• Compression of file size?

• Compression without loss of quality?

• Animation possible?

GIF

256

+

+

+

JPG

256*256*256

++

-

-

113


**--

Estimate the typical size of a computer file that contains a bitmap image in colours,

that has been obtained by using a typical scanner, and that can cover a complete typical display

or projection screen directly at optimal resolution without enlargement,

when no compression is applied.

Estimate the typical size of a computer file that contains a bitmap image in colours,

that has been obtained by using a typical scanner, and that can cover a complete typical display

or projection screen directly at optimal resolution without enlargement,

when no compression is applied.

114

Graphics formats for vector graphics (+ bitmaps)

File name extension

CDRCGMEPSIMGPPT or PPSWPG...

Origin

Corel Draw!Graphics MetafileEncapsulated PostScriptGEMMicrosoft PowerPointWordPerfect Graphics...

**--Examples

115

Graphics formats: the problem of exchange

The differences in all the graphics file formats cause the requirement of filter / conversion programs, when a graphics file must be inserted in a document which is managed by an application program which works primarily with another graphics file format.

**--

116


**--

Insert a picture, stored in a graphics file, in a document

created by your program for word processing.

Insert a picture, stored in a graphics file, in a document

created by your program for word processing.

117

Computer software

File formats for documents with text and images

***-

118


**--

Which concrete file formats for storage of documents

with text and images do you know?

Which concrete file formats for storage of documents

with text and images do you know?

119

Documents with text and images: available file formats (Part 1)

***-

• Many! Too many?

• Examples:

»formats of the various programs for word processing and page design, in their various versions (DOC,…)

»Rich Text Format (RTF)

»PostScript (PS)

»Adobe Portable Document Format (PDF); Catchword RealPage,...

120

Documents with text and images: available file formats (Part 2)

***-

»bitmap-related format, primarily for graphics, but they can also show characters: BMP, GIF, JPG/JPEG, PCX, PNG, TIFF...

»SGML, HTML, XML,... considered here together with the graphics files that they link to

»…

121


**--

Which properties of computer file formats for storage of documents

with text and images do you consider as important?

Which properties of computer file formats for storage of documents

with text and images do you consider as important?

122

Documents with text and images: properties of file formats (Part 1)

• Is the format platform independent? (for instance usable with software on Windows, Macintosh, Unix,…)

• Is the format not proprietary?

• Is the format ‘rich’, allowing to derive less rich formats from a file in this format? (for instance from Microsoft Word to RTF or HTML or PDF, from SGML to XML to HTML,...)

**--

123


• Are files in this format small in comparison to the corresponding files in other formats?

• Is compression applied? If yes, is this compression without loss of information?

• Are viewers (programs) for users easily available?

• Does the format allow text retrieval? Is the content of a file in this format searchable on a microcomputer?

• Does the format allow text retrieval by common Internet indexes? Is the contents searchable through the WWW or through an intranet?

**--

124


• Can a file in this format be loaded in a program and be edited and saved? (or can it only be derived from a master file in another format?)

• Can the text be reformatted to another size or font?

• Can a selection be made from the displayed contents of a file in this format, by copy or cut, to be pasted in another document?

**--

125


• Does the format not suffer from the existence of various versions that may confuse the users and that require an appropriate, up-to-date program?

• Is the format suitable when hard-copy documents are converted to computer-based documents?

• Is a program to produce the format already available or not expensive?

**--

126


**--

Discuss the properties (advantages and disadvantages)

of each important file format

DOC, RTF, PS, PDF, SGML, HTML, GIF, JPG, TIFFfor storage of documents with text and images?

Summarize all this in the form of a table!

Discuss the properties (advantages and disadvantages)

of each important file format

DOC, RTF, PS, PDF, SGML, HTML, GIF, JPG, TIFFfor storage of documents with text and images?

Summarize all this in the form of a table!

127


**--

What is the main conclusion of the overview of the properties

of file formats for storage of text and images?

What is the main conclusion of the overview of the properties

of file formats for storage of text and images?

128

File formats: the problem of exchange

The differences in all the file formats cause the requirement of filter / conversion programs, when a file must be viewed or edited by an application program that is not exactly the same as the one used to create the file.

**--

129

Computer software

File compression, archiving and conversion

***-

130

File compression, archiving and conversion

• Compressionto make files smaller

• Archiving to keep related files together

• Conversion for transfer via computer networks

***-

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131


***-

Which benefits are offered by compression of files?

Which benefits are offered by compression of files?

132

Data compression: benefits

Storage capacity required on magnetic or optical disks is smaller

In data communication:

»transmission times are shorter

»transfer of less bits less network congestion

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133

Data compression: redundancy

Compression is (in many cases) based on the elimination of redundancy present in the source data:

• Spatial redundancy:

repeated occurrence of the same text or picture elements

• Temporal redundancy:

occurrence of the same picture elements in subsequent pictures

**--

134

Data compression: lossless versus lossy

• Compression without loss of data / quality:“lossless” compression

• Compression with loss of data / quality: “lossy” compression

**--

135


**--

Which concrete products, tools and methods for file compression

do you know?

Which concrete products, tools and methods for file compression

do you know?

136

Data compression: some CODECS

**--Examples

• Compression without loss of data, and archiving:

ARC, BOO, CAB, LHZ, ZIP, ZOO,...

• Lossless compression of bitmap graphics:

GIF, TIFF, ... in various versions

• Lossy compression of graphics with many colours:

JPEG, ... in various versions

• Lossy compression of video with sound:

AVI, MPEG, Quicktime, RM, ... in various versions

137


**--

Find a file in .ZIP format and decompress it.

Find a file in .ZIP format and decompress it.

138


**--

Why is it not useful to apply a compression procedure

like ZIP for instance, to a video file

in formats like AVI or MPG?

Why is it not useful to apply a compression procedure

like ZIP for instance, to a video file

in formats like AVI or MPG?

139


**--

Which programs do you know and which program do you use to save images as JPEG files?

Which programs do you know and which program do you use to save images as JPEG files?

140


**--

Select or create an appropriate photograph bitmap file.

Save this file as a JPEG file under a different name.

Repeat this at about 3 very different levels of compression and thus of image quality

(always starting from the appropriate original photo file, because JPEG is a final storage format).

Load all the resulting photo files in a program to edit such files; zoom in to 400% for instance;

use tiling to display the photo files simultaneously on the screen; compare their quality.

Determine also the file size of each photo file.

Decide finally which compression level is appropriate or your aims.

Select or create an appropriate photograph bitmap file.

Save this file as a JPEG file under a different name.

Repeat this at about 3 very different levels of compression and thus of image quality

(always starting from the appropriate original photo file, because JPEG is a final storage format).

Load all the resulting photo files in a program to edit such files; zoom in to 400% for instance;

use tiling to display the photo files simultaneously on the screen; compare their quality.

Determine also the file size of each photo file.

Decide finally which compression level is appropriate or your aims.

141

Essential skills in computer use

****

Task

• File management

• Finding files

• Text editing and formatting

• “Copy and paste” from one document to the same or to another document

• Printing

Software used

• Operating system

• Word processing software(e.g. Word for Windows)

• Operating system + applications software