Transcript MC 707 - Computer Information Systems

MD703
Computer Information Systems
Lecture 1:
Changing IS Landscape - Tech. Overview
John Gallaugher
[email protected]
www2.bc.edu/~gallaugh
Issues Addressed Today
• Information Systems
– Changing IS landscape & managerial implications
– IT vs. IS; classifications of information systems
• Data / Information - what’s the difference?
• Software
– differences among operating systems
– What is Java & why is it important?
• Hardware
– What is Moore’s Law?
– What are computing & architecture alternatives?
The Changing IS Landscape
•
•
•
•
•
•
•
Y2K (year 2000 problem)
Globalization
Deregulation
The Internet
Re-engineering
Client/Server (architecture shifts)
Technology Advances: Graphical User
Interfaces, Object Programming, Low cost,
parallel computing
• Outsourcing
So What’s An IS?
• “A combination of work practices,
information, people, & information
technologies organized to accomplish goals
in an organization” (Alter, 1992).
• 5 components: (1) hardware (2) software/
programs (3) data/information (4) people (5)
procedures
• Information Technology [IT] - technology
used to create an IS.
Hardware
People
Program
Information
Computer
Systems
System
Information
Procedures
Data & Information
Potentially a Key Source of
Competitive Advantage
Data, Information, & Knowledge
• Data - raw facts, figures, and details.
• Information - organized, meaningful, and
useful interpretation of data. Has a context,
answers a question.
• Knowledge - an awareness and
understanding of a set of information and
how that information can be put to best use.
• Many firms are data rich and info poor:
victims of an old or poorly planned
architecture
Examples of Data, Information, &
Knowledge
Data: raw, no context
900,000
1,200,000
1,150,000
1,100,000
Information: meaningful, has context
Quarter 1 Quarter 2
Post
900,000 1,150,000
Kellogg's 1,200,000 1,100,000
Knowledge: information above & other information
creates an awareness of impact
Post lowered its prices after the first quarter.
Price change has caused Post sales to rise at the expense
of Kellogg’s
Software
Operating Systems
Applications
Applets
Java Challenges the Paradigm
Software
Operating Systems
provide an environment in which applications
execute (Prosise, 1996)
Application Programs
a program designed to perform a specific function
Individual examples: word processor, spreadsheet.
Collections of apps: Office 97 (suite), SAP R/3
(ERP)
Applets
small application programs which execute within a
larger environment (e.g. Java applets within
browser)
The OS Crib Sheet
OS
Windows 98
Processor
Intel x86
Most likely use:
End Users
Macintosh OS Motorola 680x0
IBM/Motorola
PowerPC
Education & Artists
UNIX
Servers & other
multi-user systems
Windows NT
Specifically
designed to run
on multiple
processors
Mostly x86;
limited availability
on others
(Compaq Alpha,
)MIPS, PowerPC)
Servers & other
multi-user systems
Pros
Largest number of
commercial
software titles
Once considered
easiest to use
Stable. Leader in
niches
Reliable, highly
scalable (can run
on PCs to
supercomputers)
More reliable than
Win95
Runs many Win95
programs
Somewhat
scaleable
Cons
Less stable
Limited to one
processor family
Not as much
software available as
Windows
Most difficult to use
Little end-user
software available
Not as scaleable as
UNIX
(runs on fewer & less
powerful machines
than UNIX)
– Win CE (pocket/palm/set-top), Win 2000, Linux
Java - a Cross-Platform Standard
• Java Consist of Two Components
– object oriented programming language
– virtual machine (software that executes Java byte
code)
• Advantages
– Write-once run-anywhere. Runs on any machine
with a JVM regardless of OS or microprocessor
– object-oriented language (reuse, faster dev.)
– secure
• Disadvantages
– 1) slow due to download times, 2) slow due to
interpreting line by line, 3) inconsistent Java VMs
Traditional Programs...
… are written for an Operating System (Windows98, Macintosh,
etc.) & compiled for a microprocessor (x86, 680x0, PowerPC,
etc.). Compiled code is ready to be executed by the appropriate
microprocessor (fast).
Netscape Navigator
for Windows
Windows
Compiler
x86
code
10010
01001...
Macintosh
Compiler
680x0
code
01011
00101...
DrawWindow()…
…
Netscape Navigator for
Macintosh
GetWindow()…
…
PowerPC 11101
code
01110...
Java Programs...
… are written for the Java Virtual Machine (JVM). In theory, the
same Java byte code can execute on any computer with a
standard JVM, regardless of OS or processor (write once, run
anywhere). Byte code is interpreted line-by-line for each
processor (slow).
Java Program
OpenWindow()…
…
Windows
x86 JVM
10110
00110...
Java
Compiler
Macintosh
PowerPC
JVM
01011
01100...
Macintosh
680x0 JVM
11000
01010...
Java byte
code
00010
11110...
Digital
Alpha UNIX
JVM
01111
01100...
...
Java is Often Confused With...
• JavaScript
– interpreted programming language that co-exists
in same files as HTML (doesn’t need to be
compiled into byte code)
– slower than Java
– easier to program
– supported by Netscape & Microsoft (w/some
consistency problems)
– unlike Java, can only be used to create web
pages (Java can be used to create stand-alone
applications that execute outside the browser).
Java is Often Confused With...
• ActiveX
– Microsoft's component technology architecture
(e.g. a way to string together pieces of reusable
code).
– Compiled, so it’s faster than Java, but not cross
platform.
– Unlike Java, it allows full access to the operating
system (including file access commands). This
means that ActiveX components are potentially
less-secure than Java (easier to spread viruses,
deploy malicious programs).
Hardware
Computers
Peripherals
Networking Equipment
Moore’s Law
Moore’s Law
Measuring Storage Capacity
– bit = zero or one, smallest computing unit
– byte = 8 bits, one Latin character
– kilobyte (K) = 1,024 bytes ~ 1 thousand bytes
– megabyte (MB) = 1,024 K ~ 1 million bytes
– gigabyte (GB) = 1,024 MB ~ 1 billion bytes
– terabyte (TB) = 1,024 GB ~ 1 trillion bytes
• Typical PC Capacity (1/99)
– RAM = 32 - 128 MB
– High Density (HD) diskette - 1.44 MB
– Hard Drives = 4 - 12 GB
– CDs = >620 MB
– DVD = 4.7 GB
Types of Computers
(the distinction is blurring)
• Personal / Microcomputers
– relatively compact, one primary microprocessor
– desktop, laptop, palmtop, PDA, specialized
• Mid-range Systems (Servers)
– may have more than one microprocessor,
typically multi-user & focused on a functional
area or task (marketing, plant management).
– Vintage midranges (proprietary OS): IBM
AS/400 (updated), DEC VAX (discontinued)
– Servers (UNIX/NT): Intel-based, Sun, H-P,
Compaq Alpha, IBM RS-6000
Types of Computers (cont.)
• Mainframes (leading mfgs: IBM, Hitatchi)
– large, expensive computer, supports multiple user
groups, terminals, run several applications at once.
– costly: support staff, air conditioning, software
– secure: centralized programs & data are easier to
backup, maintain, and monitor
• Super Computers (mfgs: IBM, Hitatchi)
– massively parallel (multiple processors)
– used to solve problems requiring long, difficult
calculations (e.g.airline scheduling, weather
prediction)
Leading IT Architectures for
Multi-user Computing
• Host / Terminal Model
• Client / Server Model
– fat clients
– thin clients
– NCs - network computers
• Architectures
– enable the range of technical options (and
hence business options) available to a firm
– implications regarding cost, flexibility, security
Host / Terminal Model
All programs & data are on
the host (usually
mainframe)
Dumb terminals display only text sent from host.
They do not perform any computing & don’t have a
microprocessor. PCs can run terminal programs to
act like dumb terminals & access hosts.
Host / Terminal Model
• Advantages
– proven, reliable technology
– less complexity (fewer vendors)
– centralized security, version control, & backup
• Disadvantages
– costly hardware & software
– aging technology
– text-based interface difficult to use
– applications are tightly integrated with database
Client / Server Computing
• Client
– a program which makes request of another
program, usually on another computer (e.g. web
browser)
– requests data or other action from servers
• Server
– a program (usually on another computer) that runs
services that are shared among multiple
client/users on a network (ex. E-mail server, web
server, database server).
– responds to client requests (delivers data, performs
tasks)
Client / Server Model
Divide & Conquer
PC executes client code
client code makes a
request
Server executes
server code &
responds to
request, holds
data
Share & Share Alike
sales
accounting
wheels
chemicals
Client/Server
• Advantages
– easier to use (PC GUI)
– faster to develop
– database separate from applications (enables
data integration across systems & reuse)
– cheaper hardware (if PCs are in place)
• Disadvantages
– complex (multi-vendor), new technology (lowers
reliability & raises maintenance costs)
– security vulnerabilities
– version control
Variants of Client/Server
Fat Clients
client code stored
(larger files, some business logic)
client code executes
Server
(some b-logic)
Data
Thin Clients (NCs, browser apps.)
client code stored
Server
(most b-logic)
Data
client code executes
(smaller files, mostly GUI)
Three-Tier (n-tier) Architecture
client code executes
(mostly GUI)
b-logic
Server
Data
NC (Network Computer)
• Advantages
– lower cost of ownership (centralized administration/
version control, reduced complexity, tighter security)
– GUI ease of use
– application & data separate
– Most appropriate for high structure & control
environments. (Ex. Delta Airlines, GM, HomeDepot)
• Disadvantages
– inappropriate for unstructured tasks
– not portable (yet)
– slow & unproven, currently few choices
Yearly Cost of Ownership
$12,000
$10,000
$8,000
$6,000
$4,000
$2,000
$0
Windows
NC
Source: Gartner Group
Types/Classifications of
Information Systems
Transaction Processing Systems
(TPS)
• A shared IS that uses a combination of IT and
manual procedures to process data and
information and to manage transactions (Senn).
• Examples: Cash Registers (POS), ATM
• Characteristics:
– transactions are similar & repeatable
– support multiple users in routine, everyday
transactions (usually tactical systems)
– data capture with possible report generation
– accuracy is critical, TPS “feed” other IS
Reporting Systems - MIS
• Sometimes called Management Reporting
Systems or Management Information
Systems
• Characteristics
– use data captured and stored from TPS
– reports consolidated information rather than
details of transactions
– supports reoccurring decisions
– provides reports in pre-specified formats (on
screen, printed, or data)
Decision Support Systems (DSS)
• Allow users interrogate computers on an ad hoc
basis, analyze information, and predict the
impact of decisions before they are made. [key:
unstructured, user-led exploration]
• Characteristics
– Assists in ad-hoc decision making
– Used when requirements, processes, or procedures
are unstructured & aren’t known in advance
– Provides info needed to define & solve a problem
– Provides information in format determined at time of
need
Management Levels & IS
Strategic
Planning
Management
Control
Operational
Control
DSS
MIS
TPS
Expert Systems (ES)
• An artificial intelligence system that uses
captured human expertise to evaluate and
solve problems
• Characteristics:
– diagnoses situations and/or recommends a
course of action
– problems are structured and repeatable
– application scope is limited to a particular
problem area (domain)
Other Types of Artificial
Intelligence (AI)
• Neural Networks
– hunt for patterns in historical data
– build their own expertise based on prior history
– require clean data & consistency between
performance history and future events
• Genetic Algorithms
– search for optimal solutions based on natural
selection: (1) propose solution (2) evaluate
results against earlier solution (3) mutate &
return to step 1