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ISYS 101 Lecture #4 1 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

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Page 1: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 1

Intro to Information Systems I

Web Publishing & Information Systems

ISYS 101

Glenn Booker

Page 2: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 2

The Internet

• Over 60% of Americans use the Internet regularly

• Media are converging on the Internet – radio stations, TV, telephone, and newspapers all are online

• Commerce is taking place on the Internet, aided by higher levels of security

Page 3: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 3

The “internet”

• Private networks also exist which use the same protocols as the Internet – these private networks are internets

• Government and large corporations create internets to support controlled exchange of data

Page 4: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 4

Interoperability

• The Internet works because many different kinds of computers (PC’s, Macintoshes, Unix workstations, mainframes, etc.) all speak the same languages – TCP/IP

• The Internet grew out of the need to get four very different computers to communicate, so scientists could share information

Page 5: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 5

Other Internet Access

• Online services, such as AOL or Prodigy, add their own custom applications on top of standard Internet applications

• “Portals” are Internet sites which add some features to encourage people to use them– Yahoo, Excite, Google, and Go are examples

Page 6: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 6

Internet Growth

• The Internet grew quietly from 1969 through the 1980’s

• Invention of the World Wide Web, an Internet application, brought the Internet into public awareness around 1994– That’s about when the “information

superhighway” term was coined

Page 7: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 7

Client versus Server Services

• Important to distinguish which Internet Services are done by the server (who hosts the web page, for example) and which are done by your computer (the client)

• Affects download time, and the amount of work the server has to be able to handle

• Most services are done by the server

Page 8: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 8

Internet Services

• Most familiar are e-mail and the WWW– Use e-mail addresses and URL’s, respectively

to define where someone or something is on the Internet

• E-mail applications include Outlook and Eudora

• WWW application include Internet Explorer and Netscape Communicator

Page 9: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 9

Internet Services

• FTP was designed specifically for transferring large files between computers– Downloading refers to copying files to

the client– Uploading copies files to the server – FTP can be limited to specific users (via a login

name and password), or anonymous FTP can be used, which allows anyone in

Page 10: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 10

Internet Services

• Usenet contains thousands of newsgroups which allow people of many common interests to find each other easily– Servers for Usenet are also called

NNTP servers– Newsgroups are mostly grouped into

hierarchies: alt(ernative), comp(uter), sci(ence), misc, soc(ial), news, and rec(reational)

Page 11: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 11

Internet Services

• IRC is the original chat application– Chat groups are on channels– Communicate by typed text

• Newer variations include AOL Instant Messenger (AOL IM), ICQ, Yahoo chat, and MSN’s chat program

Page 12: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 12

Internet Services

• Internet-based telephone and video services now exist too

• Quality and resolution aren’t great, but they’re free!

• Corporate uses include video conferencing

• Examples include WebCam and CuSeeMe

Page 13: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 13

Internet Services

• Telnet allows logging into a remote computer

• Ping asks if another computer is online

• Archie is a search tool for FTP sites

• Gopher was a menu-driven document display tool used by libraries and schools

• Veronica was a Gopher search tool

Page 14: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 14

Internet Access

• Most analog modem-based connections to the Internet use the PPP protocol– The Slip protocol is obsolete

• Shell access is a text-only Unix login

• Most users don’t get a fixed IP address on the Internet – your IP address is assigned when you log in (dynamic IP)

Page 15: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 15

Internet Access

• Most home users who aren’t on modem access use a cable modem or DSL

• Businesses tend to use an ISDN or T1 connection (if not faster)– Each computer on their LAN gets to the

Internet through a router

Page 16: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 16

Internet Addressing

• Internet addresses are given by the Internet Protocol (IP) in the form of a “dotted quad” – four numbers from 0 to 255 which are separated by periods, such as 23.124.65.222

• IP addresses are converted to and from URL’s (e.g. www.microsoft.com) by the domain name system (DNS)

Geek Comment: If you watch “The Net”, they show an IP address for the bad guy which isn’t a legal IP address!

Page 17: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 17

Internet Addressing

• A higher level of communication on the Internet is handled by the TCP protocol

• Once another computer’s IP address has been found, TCP manages the actual connection between the computers (like logging in and getting data)

Page 18: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 18

Domain Names

• There are seven top level domains (TLD):– Commercial (com)– Education (edu)– Nonprofit organizations (org)– Military (mil)– Network organizations (net)– International organizations (int)

Page 19: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 19

Domain Names

• In addition, each country has a domain– United States (us)– Canada (ca)– And so on…

• Top level domain names focus on the type of organization instead of the type of web page content

Page 20: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 20

Domain Names

• New domains are being released (probably):– name for personal pages– biz for businesses– coop for cooperative businesses– aero for the aerospace industry– museum for museums– info for anybody– pro for professionals (lawyers, accountants, ...)

Page 21: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 21

The Future of IP

• A new version of IP, called IPv6 or IPNG (for IP Next Generation), is becoming available

• Makes the IP address go from 32 bits (four groups of 8 bits each) to 128 bits (eight 16-bit groups); an IPv6 address could be:FEDC:BA98:7654:3210:FEDC:BA98:7654:3210

(In 16-bit “numbers”, the letters “A” to “F” mean “10” through “15”)

Page 22: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 22

Hypermedia

• The hyperlink made it possible to make any text into a link to jump to another document

• Now systems are developing which will automatically recognize common terms, and make them a link to some (hopefully) relevant reference material– So ‘giraffe’ might link to an encyclopedia entry

Page 23: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 23

Hypermedia

• Early web browsers were text only (such as Lynx) – later graphics, sound and video were added

• The first graphical browser was Mosaic

• A computer which runs a web service is a web server – all web pages are located on a web server somewhere

Page 24: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 24

Web Protocols

• Web pages use the HTTP protocol, which understands pages written in HTML

• HTML describes how text and images should be displayed – can be similar to using styles in Word (title, bulleted list, etc.)

Page 25: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 25

E-commerce

• More and more business is being done over the Internet

• Businesses have started catering to each other, and not just the mass consumer

• EDI is an older form of business-to-business networking specifically to conduct transactions over the Internet

Page 26: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 26

Shopping Online

• Internet-based consumer shopping has grown wildly in recent years

• Key challenges are finding ways for customers to find you (the Internet is big!), and maintaining enough stock to cater to common purchases

• Offers more selection and sometimes better prices than brick-and-mortar stores

Page 27: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 27

Secure Transactions

• Most credit card transactions over the Internet use some form of secure transmission to avoid theft of data

• Some stores get a certificate of authority (CA) to conduct secure transactions

• Others use a third party to ensure privacy, like PayPal

Page 28: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 28

Online Banking

• Banks and other businesses have discovered online transactions too

• Banks, utility companies, credit card companies, and many others can do business over the Internet

• Stock and bond trading is also done online (Ameritrade, e-trader, etc.)

Page 29: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 29

E-mail

• E-mail is a major Internet service

• A server runs different e-mail functions

• Your computer runs a client to get your mail from the server, and send outgoing mail through the server

Page 30: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 30

E-mail Protocols

• SMTP is used to send and receive text messages by e-mail

• POP stores incoming messages until you download all of them at once (from the server to your client)

• IMAP allows you to screen messages and delete some from the server, so you never have to download them

Page 31: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 31

E-mail Clients

• E-mail clients include Microsoft Outlook and Eudora

• E-mail services are also available via the WWW (e.g. Hotmail, Yahoo mail, etc.)

• Most clients also allow encryption to be used to improve security, or you can digitally sign documents

Page 32: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 32

E-mail Attachments

• E-mail attachments are handled using a protocol called MIME

• Beware of attachments which are executable files (*.exe) or Visual Basic macros (*.vbs) – they need to be checked for viruses!

• Keep attachments small (fraction of 1 MB)

Page 33: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 33

E-mail Filters

• Filters can be used to automatically route e-mail to specific folders, or delete spam (unwanted e-mail)

• Mailing lists can help send mail to lots of people at once (e.g. an entire class)

Page 34: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 34

Creating Web Pages

• A web site needs a clear purpose and audience

• Many HTML editors are available to help create your web site

• A web site is composed of one or more web pages

Page 35: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 35

HTML Editors

• Popular HTML editors include:– Microsoft FrontPage– Macromedia Dreamweaver– Adobe PageMill and GoLive– Netobjects Fusion– Allaire Homesite; Netscape Composer– Spiderwriter; HotDog; and others

Page 36: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 36

HTML Editors

• Text editors, such as NotePad or WordPad can be used to write HTML manually

• Some word processing programs can convert documents to HTML, but often badly (e.g. Word)

• Professionals may create a page with an HTML editor, then fine tune the HTML by hand

Page 37: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 37

Web Site Purpose

• Why would someone come to your web site?– To learn about you– To learn about some subject– To buy something– To socialize– To hire you– Or something else?

Page 38: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 38

Web Site Design

• Several fundamental design decisions need to be made about a web site

• The course’s web site uses a simple menu-driven structure – boring but effective

• Frames can be used to put defined structure in specific areas, but aren’t readable by all web browsers

Page 39: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 39

Web Site Design

• Some programs (e.g. FrontPage) use “shared borders” to provide continuity from page to page, and to help navigation

• Cascading style sheets (CSS) can help your site achieve a consistent look across many pages without editing each page separately for font size, style, etc.

Page 40: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 40

Web Site Design

• Your design should consider how the site will be viewed – what screen size will be used by a typical user?E.g. 800x600 pixels is a typical size

• Color is a separate issue – some colors are viewable by all graphic web browsers; these are called web safe colors, and there are 216 of them

Page 41: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 41

Web Site Design

• What download speed will the user have?– 56 kb modem (maybe less if in a lesser

developed country)– 128 kb ISDN– T1 or cable modem

• What languages will your users need? Much of the world doesn’t speak English!

Page 42: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 42

HTML

• HTML describes how the page is laid out• An HTML document is a text file which

describes the contents of the document, and how they should appear

• Some HTML content does not appear on screen– The program which used to create the page– Search criteria to help people find the page

Page 43: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 43

HTML

• Other HTML describes the background, or tells where to find images to put in the page

• HTML can include hyperlinks to documents, files, images, movies – anything you can put on a computer

• Be warned that HTML ignores extra spaces and manual line or page breaks

Page 44: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 44

HTML

• HTML can include1. Numbered lists (1, 2, 3, …)– “Unnumbered” lists (bullets)

• Structure makes a document easier to read

• HTML can include e-mail contacts

• HTML images should be in GIF or JPG format – do not use BMP files (bitmaps)

Page 45: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 45

Forms and Scripts

• Web pages can use forms to collect data (like requests for sales calls) or display the results of database queries (like a list of the Macintosh-compatible video cards for sale)

• Programming languages such as Java and JavaScript can be used for more complex activities

Page 46: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 46

XML

• XML is an emerging markup language

• Instead of defining the format of a document’s contents, it describes the type of contents

• For example, XML tags could describe a zip code, or street address, or catalog number

Page 47: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 47

XML

• The meaning of the tags can be defined in a style language, which can even define what tags can be used, and the order in which they may appear

• This helps search engines understand the difference between, for example, a site featuring Roll Over Beethoven and one dedicated to Ludwig van Beethoven

Page 48: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 48

More Web Resources

• For more on web design, see– HTML Writer’s Guild– Web Pages That Suck

• The Reference section of my web site has more resources on XML

Page 49: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 49

Information Systems

• Vast amount of data are generated every day

• The challenge of information systems is to organize that data and help find the ways it can be useful

• We call them “systems” because all aspects are needed to produce useful information

Page 50: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 50

Information Systems

• Information systems consist of:– Software – Hardware– People who create, maintain, and use them– And the documents which describe what the

hardware and software do, and how the people use and maintain them

• It’s not just software or a database!

Page 51: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 51

Life Cycle

• Information systems have a life cycle, just like people do; for the former:

• They start with an idea

• The idea is expanded into requirements

• Which lead to a design

• Which turns into a program

• Which is tested, and released

Page 52: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 52

Life Cycle

• Those steps from idea to release are called the Waterfall life cycle model

• After a system is released (actually starts being used for its intended purpose), it is maintained for a long time (we hope)

• At some point, the system is retired (replaced and/or decommissioned)

Page 53: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 53

Information and the Organization

• Information systems are sponsored by the managers who need them

• Managers may work at several levels in the organization, and that will affect the type of information they want – higher level managers look for information on longer time scales

Page 54: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 54

Information and the Organization

• Managers want information to help perform the basic management functions– Leading people by providing a guiding vision– Planning what needs to be done to meet

that vision– Organizing people into structures to get

things done– Controlling people to keep them on track

Page 55: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 55

Information Needs

• Information needs to be accessible, accurate, complete, economical, relevant, reliable, secure, simple, timely, and verifiable in order to have value

• Our greatest challenge is having too much data, and no way to find the information which could be hiding in it

Page 56: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 56

IS Roles

• Information Systems (IS) may have several common roles in a large organization

• Transaction (or data) processing to manage daily accounting

• Management IS (MIS) to distill information for various levels of managers

Page 57: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 57

IS Roles

• Decision support systems (DSS) allow for more flexible analysis than MIS systems

• Online analytical processing (OLAP) maintains constant sales or processing information

• Executive IS (EIS) support strategic (long term) planning for the entire company

Page 58: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 58

IS Roles

• Expert systems use artificial intelligence (AI) to help better understand data patterns

• Knowledge management systems try to capture and share the best practices in an organization

Page 59: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 59

IS Techniques

• How are these systems created? Common methods include:– Cooperative work, such as Lotus Notes

groupware help people collaborate on a project– Workflow automation helps speed the process

of processing using computer technology

Page 60: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 60

IS Techniques

– Business process reengineering throws out the old way of doing things, and looks for a better solution

– Data from across the company can be stored in data warehouses, and studied in many different directions using data mining

Page 61: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 61

Computers Everywhere

• Computers have long been used for retail sales at point of sale (POS) terminals (e.g. grocery stores and K-mart)

• Scanners read UPC labels to not only get the price, but also to adjust inventory

• Credit card scanners automate sales, making them much too easy!

Page 62: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 62

Computers Everywhere

• More recent systems can scan checks on the spot and verify that they’re good

• Electronic capture of signatures is also possible using a pressure-sensitive pen

Page 63: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 63

System Analysis

• To make such systems possible, a sound analysis method should be followed

• System development follows its own five-phase life cycle

1. First analyze the problem and see what kinds of ways it could be solved

Page 64: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 64

System Analysis

2. Understand the existing system before replacing it

3. Then design the new system

4. Implement the new system (including coding new software), and test it

5. Then support the system during its lifetime

Page 65: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 65

Key Tips

• Good system analysis:– Needs to involve the customer and end user so

that the final product will make them happy– Needs to be well managed– Needs to use a good problem solving method– Needs to be clearly documented; describe what

you didn’t do as well as what you did do– Needs to allow for future growth

Page 66: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 66

1. Understand the Problem

• The first phase of system development is to understand why this system is needed

• What problem is being solved?

• What kinds of ways can the problem be solved?

• Describe the approach in a proposal, including the feasibility of the project

Page 67: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 67

Feasibility

• Feasibility depends on many factors– Technically feasible means the technology can

accomplish the desired tasks– Operationally feasible means the users can use

the solution– Economic feasibility means it is financially

beneficial to fix the problem– Feasibility may allow for intangible factors too

Page 68: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 68

2. Analyze Existing Systems

• Understand how existing systems (whether manual or automated) currently solve the problem

• What can be learned about needed features for the new system?

• What aspects of the existing system need to be kept?

Page 69: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 69

3. Design the New System

• Given the requirements for the new system, develop its design

• Might need an iterative approach (keep trying)

• Might use various tools to help describe and control the design (e.g. CASE tools)

Page 70: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 70

4. Implement the New System

• Given the new system’s design, how is it best implemented? Can some form of commercial software perform most of the needed functions? Or do you need to develop a custom system from scratch? (this is the make-or-buy decision)

• Code, build, and test the new system• Convert from the old system to the new

Page 71: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 71

5. Supporting the New System

• After the new system is running (operational), maintain it

• Fix bugs

• Adapt to new software

• Add new features

• Maybe sell the system to other customers and implement it there too

Page 72: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 72

Programming

• The software in a system comes from someone programming it

• Software is written in the form of “source code”, which is translated into usable form for the computer

• Programming languages have evolved little over the last 50 years

Page 73: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 73

Compiled vs. Interpreted

• Compiled programming languages (e.g. C) are converted into an executable program by a compiler– Word.exe is an executable program, MS Word

• Interpreted languages never get compiled; instead they are interpreted one line at a time when needed– Basic and Java are interpreted languages

Page 74: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 74

Compiled vs. Interpreted

• Compiled languages are much faster than interpreted ones

• Regardless of compiled versus interpreted, mistakes can be made which lead to bugs in the software

• Structured programming should help prevent bugs, but it often not used in reality

Page 75: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 75

Object-oriented Languages

• Object-oriented programming languages (OOPLs) use a different frame of reference than procedural languages

• OOP turns relevant nouns into “objects” and uses programs (“methods”) to describe how those objects interact with each other– Smalltalk, Ada95, C++, and Java are OOPLs

Page 76: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 76

Who’s Who in Programming

• Cobol is still the most widely used language, because so many business applications were written in it– Very user friendly command structure– Used to create and maintain flat file databases

• Fortran is the oldest language (1953), and is still used for scientific programming

Page 77: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 77

Who’s Who in Programming

• Ada was developed by the US military to consolidate systems into one common language– Now used primarily for high reliability and real

time systems

• Basic was a classic first language – slow and weak, but easy to learn

Page 78: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 78

Who’s Who in Programming

• Pascal replaced Basic as the common first language in the 1980’s– Well structured, it became the basis for Ada

• “C” was developed for writing operating systems, but eventually became a dominant language anyway

• Smalltalk was an early object-oriented language

Page 79: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 79

Who’s Who in Programming

• C++ is an object-oriented version of C

• Java tried to fix the problems in C++– Java was supposed to be the ultimate write-it-

once, run-it-on-any-computer language

• Visual Basic, C++, and J++ take Basic, C++, and Java, and add a development environment around them

Page 80: ISYS 101Lecture #41 Intro to Information Systems I Web Publishing & Information Systems ISYS 101 Glenn Booker

ISYS 101 Lecture #4 80

Software Development

• Software development follows a life cycle model, like the Waterfall model presented earlier

• Other life cycle models exist, but they’re all based on the same kind of fundamental activities – requirements analysis, design, code, and test.