Lecture 2A: The Big Picture, Application Architecture and Lifecycle IT 202—Internet Applications...
-
date post
19-Dec-2015 -
Category
Documents
-
view
215 -
download
0
Transcript of Lecture 2A: The Big Picture, Application Architecture and Lifecycle IT 202—Internet Applications...
Lecture 2A:The Big Picture,
Application Architecture and Lifecycle
IT 202—Internet ApplicationsBased on notes developed by Morgan Benton
For Today
How this course fits in the CCS curriculaHistory of Networked ApplicationsThe Big PictureSemester RoadmapInformation Technology Systems Architecture Networked Computing Infrastructure The Internet
Application Development Rationale Acquisition Development Lifecycle
How does this course fit in?
Supply Chain Management
Databases
Client-servercomputing
InterfaceDesign/Human Factors
MISBPR
E-commerce
Brief History of Computing
4 Major phases: Centralized Time-shared Decentralized Networked
Two points to get from this: See where we’ve come from Guess where we’re going
What’s an Internet Application?
Three Ingredients:1. Information Technology (e.g. networks)
2. Information Content
3. Applications and Users
Social Applications
Characteristics of User Groups Number of Users Narrowness of purpose Duration of activity Social relationships
Examples of types of groups Individuals Task group/Work group Interest group Citizenry
Styles of Social Applications I
Communication Style Direct vs. Publication dimension (support?) Synchronous (immediate) vs. Asynchronous (deferred) Same place vs. Different place
Synchronous Asynchronous
Same Place Brainstorming, DSS, etc.
Sticky notes
Different Place Chat, videoconferencing
E-mail, message boards
Styles of Social Applications II
Coordination Styles Parallel Pooled Sequential Reciprocal/Reactive
The content of this slide is borrowed from Murray Turoff’s CIS 679 course notes, but based on Coordination Theory which was initially developed by Thomas Malone at MIT’s Sloan School of Business
Types of Social Applications
Remote Conferencing (synchronous)Groupware (async)Discussion Forums/ChatCyberspace Applications Broadcast, mass publication Information Retrieval E-commerce Recommender systems
Finding Useful Information
Information Search and Retrieval
Push vs. Pull
Automated vs. Personalized
Recommendations
User Control
Information Overload
According to Hiltz and Turoff (1981), users experience the greatest amounts of information overload at intermediate levels of use. New users and more experienced users have lower levels.It is very important to be careful about how information serving is designed
Hiltz, S. R. and Turoff, M. (1981) The Evolution of User Behavior in a Computer Conferencing System. Communications of the ACM 24(11), November 1981
Organizational Applications
Apps are designed to support activity Within departments Across departments, within same organization External to the organization, i.e. with
customers, suppliers, business partners, etc.
Types of Organizational Apps
Transaction Processing Systems (TPS)
Management Information Systems (MIS)
Executive Information Systems (EIS)
Enterprise Resource Planning (ERP)
Decision Support Systems (DSS)
Knowledge Management (KM)
Data Mining (DM)
E-Commerce Framework
Consumer Business Government
Consumer C2C C2B C2G
Business B2C B2B B2G
Government G2C G2B G2G
Steps in a Sale
Matching buyers and sellers
Negotiating terms and conditions
Consummation
Customer Service
Critical Societal Infrastructure
It is important to understand just how important computing and networked applications have become to the smooth operation of our society
What would happen if there was a sudden failure in networked computing?
The Productivity Paradox
Despite the obvious hours and days of effort that are saved by computers, it is often hard to see an impact on measures of productivity—i.e. people are working more than ever, not making significantly much more money, etc.
Roadmap for the Semester
Understanding the theory and practice of implementing Internet applications
By the end of the semester you may be able to identify a niche that you would like to pursue for your own career
Information Technology
“…the suite of computing and communications technologies that empower users and organizations to capture, store, communicate, and manipulate information. These technologies provide an infrastructure—those capabilities not specific to any application, but which support all applications—together with the application-specific software.” (Messerschmitt)
Information Content
Networked applications restricted to transmission of bit-encoded info, but MANY types of info can be encoded
On the internet a mime-type code often tells a client program (e.g. web browser, mail client) how to interpret a given bit stream (for more info see RFC’s 2045-2049)
System Architecture
“…a system is something that puts together building blocks that interact to accomplish some higher-level purpose—a purpose that the building blocks themselves could not individually accomplish. Systems can be social (like an organization) or technical (like a networked computer system).” (Messerschmitt)
Building blocks of a Networked Application Architecture
DatabasesUser
DesktopComputer
The Internet
Server
LAN
Elements of an Architecture
DecompositionFunctionalityInteraction
These elements combine together to form emergent properties—i.e. those properties that only appear because the elements work in unison
Network Infrastructure I
Supports four important capabilities:1. Communication across distance
2. Communication across time
3. Computation and logic
4. Human-Computer Interface
Network Infrastructure II
DatabasesCommunication
AcrossDistance
CommunicationAcrossTime
ComputationAnd
Logic
HumanComputerInterface
Web Host Machine(aka a “server”)
System Layers: An Example
Web Application
Application Server
Web Server
Operating System
e.g. Amazon.com website
PHP, ASP, JSP, ColdFusion, etc.
Apache Web Server, IIS, etc.
Linux, Windows, etc.
…to the Internet…
also relies on other components not shown here,such as a database server, DBMS, etc.
Network Functions
Primarily Communication
Domain Name resolution via DNS (Domain Name Server/Service)
Authorization/Authentication
Reliable packet transmission
Storage
File Systems
Databases (DBMS) Isolate application from changes in computer
systems Provide standard data handling operations Support multiple applications Provide safety and integrity
So how do these things get built?
Organizations acquire networked applications in one of three ways: Buy them off-the-shelf Outsource them Build them internally (or some combination of these three)
These decisions are quite complex and there are no hard and fast rules that apply
Application Lifecycle
Requirements Analysis
System Design
Implementation
Building and Testing
Deployment
Maintenance
Retirement
What we’ll do this semester