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

Intro to Information Systems I
Web Publishing & Information
Systems
ISYS 101
Glenn Booker
ISYS 101
Lecture #4
1
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
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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
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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
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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
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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
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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
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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
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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
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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)
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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
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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
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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
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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)
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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
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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!
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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)
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Domain Names
• There are seven top level domains (TLD):
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Commercial (com)
Education (edu)
Nonprofit organizations (org)
Military (mil)
Network organizations (net)
International organizations (int)
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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
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Domain Names
• New domains are being released (probably):
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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, ...)
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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 16bit 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”)
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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
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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
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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.)
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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-tobusiness networking specifically to conduct
transactions over the Internet
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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
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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
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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.)
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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
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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
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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
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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)
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E-mail Filters
• Filters can be used to automatically route email 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)
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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
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HTML Editors
• Popular HTML editors include:
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Microsoft FrontPage
Macromedia Dreamweaver
Adobe PageMill and GoLive
Netobjects Fusion
Allaire Homesite; Netscape Composer
Spiderwriter; HotDog; and others
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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
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Web Site Purpose
• Why would someone come to your
web site?
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To learn about you
To learn about some subject
To buy something
To socialize
To hire you
Or something else?
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Web Site Design
• Several fundamental design decisions need
to be made about a web site
• The course’s web site uses a simple menudriven structure – boring but effective
• Frames can be used to put defined structure
in specific areas, but aren’t readable by all
web browsers
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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.
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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
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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!
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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
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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
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HTML
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HTML can include
1. Numbered lists (1, 2, 3, …)
– “Unnumbered” lists (bullets)
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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)
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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
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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
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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
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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
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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
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Information Systems
• Information systems consist of:
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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!
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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
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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)
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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
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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
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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
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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
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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
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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
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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
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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
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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!
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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
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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
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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
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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
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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
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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
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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?
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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)
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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-itonce, run-it-on-any-computer language
• Visual Basic, C++, and J++ take Basic,
C++, and Java, and add a development
environment around them
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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.
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