Transcript Slide 1

MIT5312: Professor Kirs
Systems Concepts Introduction
A Brief Overview of
System Concepts and
Terms
Slide 1
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 2
Why are we taking this course???
Good Question!!
1. Its required
2. The course you really wanted wasn’t available
3. The course fits your schedule
No, Really – I don’t want to be a Systems Analyst
Be quiet – I Do!!
Whether you do or don’t, you will somehow be involved
with an information system:
1.
2.
3.
4.
Purchase Decision,
Analysis,
Design, or
Implementation
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 3
Alright, Alright – Where do we start???
With some basic concepts and terminology
Sounds boring --Maybe – But necessary
??? Why ???
• To ‘level’ the playing field
• So that we are all aware of the same
basic concepts
• So that we are all speaking the
same language
• Because I have some time to kill
and enjoy torture students
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 4
Systems
• A system may be defined as:
“a group of independent but interrelated
elements comprising a unified whole”
• ALL the components must work together toward a single
goal
• In fact it is many different and related systems that appear
to be only one system
• It is a term that we use everyday, without thought to what
it really means:
“I don’t understand why they chose the new
inventory system instead of an SAP system”
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 5
Systems
• Basic system characteristics:
• A system is viewed as a single “thing”
“The neighbors have a new TV surround-around System”
• A system is not isolated
“They can’t get the rear speakers to work with the DVD player”
• If any component collapses, the entire system collapses
“Can you believe they paid all that money for a system that doesn’t
work”
• A system appears complicated
“I don’t know why they sell systems like that that no one can understand”
• A system will eventually collapse
“Too bad the old system broke – It was much easier”
• A system is Synergistic
“When they had everything working together, it was a thing of beauty”
MIT5312: Professor Kirs
Systems Concepts Introduction
Systems
• Some System Elements:
 Purpose: The reason for the
system’s existence.
Sometimes we can clearly define a system’s purpose:
• Thermostat: To control temperature
• Stereo System: To provide music
Sometimes we can imply a system’s purpose:
• Digestive System: Break-Down Foods
• Ecosystems: Maintain the environment
Sometimes we aren’t really sure:
• The Solar System
( But we know it is a system)
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MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 7
Systems
• System Elements
 Purpose: The reason for the system’s existence.
 Subsystems: A component of a system which is a
system in its own right. (Also called components)
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 8
Systems
• System Elements
 Purpose: The reason for the system’s existence.
 Subsystems: A component of a system which is a
system in its own right. (Also called components)
 Boundary: The extent of the system.
 Environment: Everything outside
the boundary that relates to the
system.
 Inputs: Items enter the system from
the environment.
 Outputs: items that exit the system.
Rental Car
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 9
Systems
• System Elements
 Purpose: The reason for the system’s existence.
 Subsystems: A component of a system which is a
system in its own right. (Also called components)
 Boundary: The extent of the system.
 Environment: Everything outside the boundary that
relates to the system.
 Inputs: Items enter the system from the environment.
 Outputs: Items that exit the system.
 Interfaces: Connections between
the system and its environment,
can be used for security, filtering.
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 10
Systems
• System Elements
 Purpose: The reason for the system’s existence.
 Subsystems: A component of a system which is a
system in its own right. (Also called components)
 Boundary: The extent of the system.
 Environment: Everything outside the boundary that
relates to the system.
 Inputs: Items enter the system from the environment.
 Outputs: Items that exit the system.
 Interfaces: Connections between the system and its
environment, can be used for security, filtering.
 Constraints: Factors acting to limit the
functioning of the system (Controls).
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 11
Systems
• Basic principles associated with Systems:
• Decomposition: being able to breakdown a systems into its
components (reductionism)
• dealing with smaller, less complex processes
??? Why ???
• System-wide processes are too complex
• Consider a stereo system. It contains:
• Bass Volume
• Woofers
• Tweeters
WE CAN CONTROL THE OVERALL SOUND DELIVERED ONLY
BY CONTROLING THE INDIVIDUAL COMPONENTS
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 12
Systems
• Basic principles associated with Systems:
• Decomposition: being able to breakdown a systems into its
components (reductionism)
• Modularity: results from decomposition; degree to which the
system can be seen as a collection of self contained subsystems
??? Why ???
• Again, it is an issue of complexity
• It we couldn’t break down our stereo system into:
• A Tuner
Each component a system itself
• A CD Player
• A Tape Player
WE WOULD NOT BE ABLE TO DEAL WITH THE INDIVIDUAL
COMPONENTS
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 13
Systems
• Basic principles associated with Systems:
• Decomposition: being able to breakdown a systems into its
components (reductionism)
• Modularity: results from decomposition; degree to which the
system can be seen as a collection of self contained subsystems
• Coupling: the degree to which subsystems are dependent on
each other.
??? Why ???
• We must understand the relationships between the components
• If we didn’t know that the CD player worked off the tuner
WE WOULD NOT BE ABLE TO GET THE CD PLAYER TO
WORK
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 14
Systems
• Basic principles associated with Systems:
• Decomposition: being able to breakdown a systems into its
components (reductionism)
• Modularity: results from decomposition; degree to which the
system can be seen as a collection of self contained subsystems
• Coupling: the degree to which subsystems are dependent on
each other.
• Cohesion: the extent to which a system or subsystem performs a
single function.
??? Why ???
• All of the components of the system must appear to work together
THINK OF ALL THE COMPONENTS INVOLVED IN AN A/V
SURROUND-ARROUND SYSTEM WITH A CABLE, DVD, VCR, ETC.
MIT5312: Professor Kirs
Systems Concepts Introduction
Systems
• Systems may be classified into 2 major types:
• Closed Systems: Those which do
not interact with the environment
• Consider a stand-alone computer system
• Open Systems: Open systems are
organic and must interact with their
environment in order to maintain their
existence
• Consider an internet computer
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MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 16
Systems
• Closed Systems:
• Mechanical systems are generally closed systems
To use a refrigerator you turn it on and set the
temperature. After that you can forget about
monitoring the temperature because it is done
automatically.
• You might consider a prison system as a closed
system (especially if a prisoner is locked-up in
isolation)
• A simple computer program which always returns the
same result may be considered a closed system
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 17
Systems
• Open Systems:
• Living Organisms
People are open systems since they must
interact with their environment in order to take
in food, water, and obtain shelter
• Some mechanical systems, such
as thermostats,
which rely on inputs from the
environment
and produce affects affecting the
environment
MIT5312: Professor Kirs
Systems Concepts Introduction
Information Systems
• The emphasis here is that we are once again dealing
with a SYSTEM, not just an isolated program
• An information system is an relationship between:
•
•
•
•
•
•
•
•
People
Functional Areas
Data
Organizational processes
Specific Processes
Interfaces
Networks
Information Technologies
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MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 19
Information Systems
• Information systems should be viewed the same as any
other system
•
•
•
•
The solar system
A railway system
An ecological system
An economic System
(The European Community)
• They are:
“a group of independent but interrelated
elements comprising a unified whole”
• ALL the components work together toward a single goal
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 20
Information Systems
• Information Systems have the same characteristics of all
Systems :
• An Information system is viewed as a single “thing”
“I hate the new accounting system”
• A system is not isolated
“The A/R system doesn’t correspond to the General Ledger”
• If any component collapses, the entire system collapses
“The system doesn’t work because the A/R system is messed-up”
• A system appears complicated
“I don’t understand why the A/R system needs all those entries”
• A system will eventually collapse
“Too bad the old system broke – It was much easier”
• A system is Synergistic
“When they had everything working together, it was a thing of beauty”
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 21
Information Systems
• Information systems share the same system parameters
 Purpose: The reason for the existence of the system.
“We need an inventory system”
 Subsystems: A system component which is also a system
“It must have automatic reordering capabilities”
 Boundary: The extent of the system
“Due to budgetary constraints, we can’t include bulk discounts”
 Environment: Everything outside the boundary that relates
to the system.
“Inputs will be made only by the supervisors in the inventory department”
 Inputs: items that enter the system from the environment.
“Additions to inventory will be made by scanning the new item UPC codes
and entering the amounts manually”
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 22
Information Systems
• Information systems share the same system parameters






Purpose: The reason for the existence of the system.
Subsystems: A system component which is also a system
Boundary: The extent of the system
Environment: Everything outside the system boundaries
Inputs: items that enter the system from the environment.
Outputs: items that exit the system
“The system will produce reports of weekly, monthly and yearly consumption
by item and by category”
 Interfaces: Connections between the system and its
environment; can be used for security, filtering.
“Entry to the system will be password protected”
 Constraints: internal and external factors which act to
limit in some way the functioning of the system (Controls).
“To assure accuracy, all additions must be double-entered”
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 23
Information Systems
• A basic system can be represented as
Feedback
Signals
Feedback
Signals
Control
Control
Signals
Control
Signals
Input
Processing
ENVIRONMENT
Output
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 24
Information Systems
• Information Systems also share the same basic principles
associated with Systems:
• Decomposition: being able to breakdown a systems into its
components (reductionism)
• Modularity: results from decomposition; degree to which the
system can be seen as a collection of self contained subsystems
• Coupling: the degree to which subsystems are dependent on
each other.
• Cohesion: the extent to which a system or subsystem performs a
single function.
??? Why ???
We will see that when we discuss how we go about analyzing and
designing information systems
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 25
Information Systems
• For our purposes, we should realize that an information
system’s sole purpose is to add value to the organization
• Many failed systems were abandoned because analysts
tried to build wonderful systems without understanding the
organization or the users of the system.
• An information system must support and improve the
day-to-day operations in a business (Data Processing)
• An information system must support and improve the
problem solving and decision making needs of
management (Information Services/Decision Support)
• An information system should provide the organization
with a competitive edge (Strategic Advantage)
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 26
Information vs. Data
• While information systems rely on data, they must provide
information
What’s the difference???
• Data (pl) is a non-random sequence of symbols
Fernandez, Juan A19 1211 83 77 81
• Information, while generally based on data, is something
that increases our knowledge
Juan Fernandez is an Accounting Major and has a 80.3 average in
Principles of Accounting
(Based on analysis of the above data)
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 27
The Value of Information
• Information has a number of measures of value:
• Relevance - How useful is the information to the user?
• Does it help the user perform their job better?
• Does it make the user’s job easier?
• Does the user feel more confident about the results?
• Accuracy - Extent of errors in the outputs
• Are more appropriate decisions being made?
• Completeness - Does it cover all the important aspects?
• Are important components missing?
• Timeliness – Is the information delivered when needed?
• Is the data out of date?
• Reliability - What is the source of the information?
• Can the validity of the data be shown?
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 28
The Value of Information
• Information has a number of measures of value:
•
•
•
•
•
•
Relevance - How useful is the information to the user?
Accuracy - Extent of errors in the outputs
Completeness - Does it cover all the important aspects?
Timeliness – Is the information delivered when needed?
Reliability - What is the source of the information?
Verifiability - ability to check or cross check the data
• Can the outputs be duplicated?
• Understandable - Can the user comprehend the information?
• Is the information too complex?
• Economical - how much does it cost to produce?
• Is the information worth it?
• Flexible - how many purposes can it serve?
• Can the information be used for multiple applications?
MIT5312: Professor Kirs
Systems Concepts Introduction
What is Systems Analysis and Design???
• Systems Analysis is the study of a business
problem for the purpose of recommending
improvements and specifying the business
requirements for the solution
• Systems Design is the specification of a
technical, computer-based solution for the
business requirements identified in the
systems analysis
(Note that programming is NOT
required)
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MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 30
Who is involved in the Information Systems
Development Process ???
• The Systems Trinity:
• The Manager (the person in charge)
• Systems Designer (Systems Analyst)
• The User (The person who will actually use the system)
Managers
Systems Analyst
Users
ALL of whom must be involved in the development
process (Or the system will probably fail)
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 31
?? How does that work ??
• The Systems Trinity should be viewed
as a three-legged stool:
• System failure can be caused by any of
the participants:
• A bad design by the Systems Analyst
• Lack of User Involvement in the design and implementation
• Lack of Manager Support
(Especially at the upper levels)
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 32
?? How are managers involved ??
• Ultimately, the manager is responsible
for the system
• S/he is responsible for the department
or functional area productivity
• S/he is responsible for the costs
involved in system development
I am the boss!!
• S/he is the person who must report to top management
• S/he is the person who ultimately
must approve of the system
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 33
?? Why Involve Users ??
• In the 1980’s, A Cruise Ship Line Noticed they had a problem:
• What Was a Large Source of Revenue?
-- Gambling
(as soon as they were in
International Waters)
• Unlike Casinos, they couldn’t have high ceilings with
sophisticated surveillance
• Space is at a premium
• Gambling was not so large a business
that they expend all the resources
needed
MIT5312: Professor Kirs
Systems Concepts Introduction
?? Why Involve Users ??
• What Could they do?
• Ask Customers not to cheat
• Put in a lot of surveillance Cameras
-- For some odd reason, gamblers
did not seem to enjoy themselves
much with a battery of cameras
staring at them
Slide 34
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 35
?? Why Involve Users ??
• What did they do?
• They hired a consulting firm dealing in electronic
(computerized) security systems
• What did they come up with?
• A simple system for the Black Jack Table
• Cards would be coated
• At the end of each hand, the cards would be swept into a
slot, where they would be read
• Statistical calculations would be made about who was
naughty and nice
• Expensive?
• About $15M
-- Chump-change for an organization that large
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 36
?? Why Involve Users ??
• Was the System built?
• Yes – by the consulting firm
• What happened?
• Just before they installed it, the company decided that
they had better show the users (black jack dealers) how to
use the system
• And?
• Well, what do you usually find at a Black Jack Table?
• Cards
• Chips
• Drinks
-- Absolutely!
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 37
?? Why Involve Users ??
• And?
• A strange thing happened:
• By Accident, within an hour or so, all of the dealers
knocked over a customer’s drink, which just happened
to spill into the hardware (the slot where the cards
were swept), ruining the circuitry
• And then?
• A lot of managers in Miami started looking for new jobs
The Moral of the Story:
Treat users like mushrooms and
they will poison you !!
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 38
Why do businesses need Systems Analysts ???
• As we will see, originally, they didn’t
• Systems/Programs were straight-forward and only
programming
• Now, systems analysts are needed to
bridge the communications gap between
those who need the computer and those
who understand the technology.
• This reflects the change in required
analyst skills
• From technical to oral and written
communication skills
MIT5312: Professor Kirs
Systems Concepts Introduction
What does a Systems Analyst do???
• Study business problems and opportunities
and then transform business and
information requirements into computerbased information systems
• Sell the system to managers and users
• Supervise technical staff in the
implementation of the chosen system
Slide 39
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 40
Where does a Systems Analyst work???
That used to be a very simple question:
• In the traditional business environment, Information services
were centralized for the entire organization
• Analysts worked along side programmers in
permanent teams to develop programs for a
specific functional area
• In Information Services Centers, or development Centers, they
still do as:
• Systems/Applications Developers
• Data Administrators
• Network/Telecommunications Administrators
MIT5312: Professor Kirs
Systems Concepts Introduction
Where does a Systems Analyst work???
Now it is much more complicated:
• With the development of information systems
and end-user computing, analysts may work
in any area of the organization:
• End-User Consultants
• Help desk Advisors
• Installation/Training Providers
• And others
(More on this later)
Slide 41
MIT5312: Professor Kirs
Systems Concepts Introduction
What skills must an Analyst have???
• General Business Knowledge
• The ability to merge organizational objectives,
functional needs, technology, and user
requirements
• Problem Solving Skills
• The ability to analyze problems in terms of cause
and effect rather than in terms of simple remedies
• Interpersonal Skills
• The ability to relate to managers, users and
technical staff
Slide 42
MIT5312: Professor Kirs
Systems Concepts Introduction
What skills must an Analyst have???
•
•
•
•
General Business Knowledge
Problem Solving Skills
Interpersonal Skills
Communication Skills
• The ability to communicate effectively,
both orally and in writing
• Flexibility/Adaptability
• No two systems development are the same; the
analyst must learn to change their approaches to
meet needs
• Technical Skills
• Although programming is not as important as before, the
analyst must still be aware of the latest technology and
understand and appreciate programming concepts
(A good programmer can not necessarily be a good analyst)
Slide 43
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 44
What career opportunities are available???
• According to the Bureau of Labor statistics, opportunities
for Systems Analysts are expected to increase much
faster than the average for all professions
• The number of systems analysts increased by
approximately 250,000 between 1998 and 2000 (36%
increase
• Systems Analysis is ranked as the 12th fastest growing
occupation
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 45
Anything else I should know about systems
and systems analysts ???
Of Course!!! That’s why you’re taking this course !!
??? Any Questions ???
I’ve got lots of questions, but I know that no
one else does, and I hate to look stupid --BETTER TO JUST NOT KNOW!!!
MIT5312: Professor Kirs
Systems Concepts Introduction
Slide 46