SDLC Phase 2 - Systems Analysis
Stage 1 - Determine Requirements
Stage 2 - Analyze Requirements
Stage 3 - Evaluate Alternatives and Strategies
Objectives
Evaluate various alternatives when planning
systems development and acquisition
Explain the advantages and disadvantages of
in-house development versus purchasing a software
package
List the steps in purchasing and evaluating
a software package
Describe the contents of the system requirements
document and explain its purpose
Explain the prototyping process
Describe computer-aided software engineering
(CASE) tools
Explain how systems flowcharts are used
Introduction
Chapter 6 covers the remaining tasks in the
systems analysis phase
Evaluation of
alternative solutions
Preparation
of the system requirements document
Presentation
to management
Evaluating Software Alternatives
Make or buy decision
Develop software
in-house
Purchase a software
package
Customize a
software package
Outsourcing
End-user (or
departmental) computing
Developing software in-house
Reasons for
in-house development
Satisfy unique requirements
Minimize changes in business procedures and policies
Meet constraints of existing systems
Meet constraints of existing technology
Develop internal resources and capabilities
Buying a software package
Reasons for
buying a software package
Lower costs
Requires less time to implement
Proven reliability and performance benchmarks
Implemented by other companies
Requires less technical development staff
Future upgrades provided by the vendor
Customizing software packages
Purchase a basic
package that can be customized to suit your needs
Negotiate with
software vendor to make enhancements to suit your needs
Purchase the
package and make your own modifications
Outsourcing
Using outside
companies to handle part of the workload, on short-term or long-term basis
Contract personnel
firms
Systems management
or facilities management firms
End-user systems
Major factor
in systems planning and development
Applications
can be managed by end-users
Software suites
offer integrated applications
Interactive
Help features include wizards
Security concerns
might require read-only files
Information
centers (IC) can support end-user systems
Selecting a software alternative
Decision will
affect remaining SDLC phases
Systems analyst’s
involvement depends on which alternative is selected
Steps in Evaluating and Purchasing Software Packages
Five step process
1. Evaluate the information system requirements
2. Identify potential software vendors
3. Evaluate software package alternatives
4. Make the purchase
5. Install the software package
Step 1: evaluate the information system requirements
Identify the
key features of the system
Estimate volume
and future growth
Specify any
hardware constraints
Prepare a request
for proposal or quotation
Step 2: identify potential software vendors
Next step is
to contact potential vendors
An RFP will
help vendors to identify solutions
Various sources
of information on suppliers
Retailers
Computer manufacturers
Industry trade journals
Systems consultants
Step 3: evaluate software package alternatives
Object is to
compare software packages and select the best alternative
Obtain information
from many sources
Vendor presentations and literature
Product documentation
Trade publications
Companies that perform software testing/evaluation
Contact users of the package
Benchmark test
Step 4: make the purchase
Software licenses
Lease agreements
Maintenance
agreements
Step 5: install the software package
Installation
time depends on size and complexity
Before using
the package, complete all implementation steps
Loading, configuring, and testing the software
Training users
Converting data files to new format\
Hardware Alternatives
Hardware decisions use the same five-step approach
as software decisions
1.Evaluate system requirements
2.Identify potential hardware
vendors
3.Evaluate hardware alternatives
4.Make the purchase
5.Install the hardware
Other issues to consider
Turnkey systems
Site preparation
New workstations
Network cabling
Raised floors
Conditioned electrical lines
Fire extinguishing equipment
Uninterruptible power supplies (UPSs)
TRADEOFF
How do you select the best alternative?
Most companies combine
In-house developed
software
Software packages
Outsourcing
End-user systems
Object is to develop a list of viable alternatives
All viable alternatives must be evaluated
Feedback from users is essential
Completion of Systems Analysis
System requirements document
Also called
software requirements specification
Describes alternatives
and makes recommendation to management
Similar to a
contract for what will be delivered
Must be clear
and understandable to users
Document contains
design for the new system
Must reflect
thorough analysis and effective communication
An accurate
and understandable document is essential
Presentation to management
Presentation guidelines and suggestions
Give overview of the project’s purpose and objectives
Summarize alternatives, with costs, pros, and cons
Explain why the recommended alternative was chosen
Allow time for discussion, questions, and answers
Obtain final decision from management or timetable for next step
Five probable management decisions
1. Develop an in-house system
2. Modify the current system
3. Purchase or customize a software package
4. Perform additional systems analysis work
5. Stop all further work
Prototyping
A prototype is an early, rapidly constructed
working version of the system
A working model helps users understand the
system
Prototyping produces a less-expensive model
Can eliminate problems before the final version
Prototyping during systems analysis
Goal is to develop
a working model quickly
Early way to
test essential system features
Prototype can
be upgraded or replaced during later SDLC phases
Prototyping
Nonprocedural
tools specify the problem to be solved, rather than how to solve it
Fourth-generation
environment prototyping tools
CASE toolkit
Report writer or report generator
Query language
Screen generator, screen painter, screen mapper, or form generator
Program generator or code generator
Computer-Aided Software
Engineering (CASE)
CASE tools increase productivity
Full set of CASE tools is called a toolkit
CASE tools can handle variety of tasks
Create and integrate
data flow diagrams
Logical and
physical design
Generation of
program code
TRADEOFF
Pros and cons of CASE tools
Advantages
Automate manual
tasks
Encourage standard
methods
Improve accuracy
and overall quality of end product
Disadvantages
Cost of CASE
software and hardware needed
Lack of CASE
standards
Other issues
CASE does not
replace need for analyst’s skills
Initial preparation
effort not always worthwhile
Transition to Systems Design
Next SDLC phase is system design (for in-house
system development)
Size of the development team depends on the
company and the nature of the project
System requirements document
An accurate
and understandable document is essential
Document contains
design for the new system
Must reflect
thorough analysis and effective communication
Logical vs. Physical Design
Logical design
defines necessary system requirements
Logical design
specifies what must take place, not how it will be accomplished
Physical design
concerns how the system will be implemented
Physical design
describes specific components and system specifications
The relationship between analysis and design
Logical and
physical design are related closely
Analysis should
be completed before design
Developers do
not return from design to analysis work except in limited circumstances
An important fact is overlooked
Users have significant new needs
Legal/governmental requirements change
Unforeseen design issues or problems arise
Systems design activities
Design the system
Output
Input
Files and databases
System architecture
Present the
system design
System design specification document
General Guidelines for Systems Design
Characteristics of a well-designed system
Effective
Satisfies defined requirements
Accepted by users
Reliable
Adequately handles errors (input, processing, hardware, or human mistakes)
Maintainable
Well-designed and flexible
Future modifications considered
Design suggestions
Three categories
of considerations
User considerations
Data considerations
Processing considerations
User considerations
Make the system
user-friendly
Consider where
users receive output, or provide input to the system
Anticipate future
needs
Users
Information system
Organization
Data considerations
Enter data where
and when it occurs
Verify data
where it is input
Use automated
data-entry methods
Control access
for data entry
Report all entries
or changes to critical values
Enter data into
a system only once
Avoid data duplication
Processing considerations
Use a modular
(structured) design
Design modules
that perform a single function
Design tradeoffs
Design goals
often conflict with each other
Easier use might create more complex programming requirements
More flexibility might increase maintenance needed
Meeting one user’s requirements might make it harder to satisfy another’s
needs
A major issue
is quality versus cost
TRADEOFF
Good design: the flexibility issue
Hardcoded (fixed)
values are inflexible
Users’ needs
constantly change
Variable parameters
can provide flexibility
Default values
can be combined with user-defined parameters
Designing and Using Codes
A code is a set of letters or numbers that
represents an item of data
Codes serve many useful purposes
Save storage
space and costs
Reduce data
transmission time
Decrease data
entry time
Can reveal or
conceal information
Can reduce input
errors
Types of coding
Sequence codes
Block sequence
codes
Classification
codes
Alphabetic codes
Mnemonic codes
Significant
digit codes
Derivation codes
Cipher codes
Action codes
Self-checking
codes
Developing a code
Keep codes concise
Allow for expansion
Keep codes stable
Makes codes
unique
Use sortable
codes
Avoid confusing
codes
Make codes meaningful
Use a code for
a single purpose
Keep codes consistent
Introduction to Output Design
Users judge a system based on how well the
output helps them perform their jobs
Output must be
Useful
Accurate
Understandable
Timely
Checklist for output design
Design process
depends on
What is the purpose of the output?
Who or what wants this information, why is it needed, and how will it be
used?
What information will be included?
What format should be used?
When will information be provided, and how often must it be updated?
Will simultaneous user access be required?
Are security or confidentiality issues involved that need to be considered?
Types of Output and Information Delivery
Technology affects how people communicate and
obtain information
Printers
Screens
Plotters
Audio output
E-mail
Links to Web
pages
Automated facsimile
system
Computer output
microfilm (COM)
Other specialized
devices
Printed output
Impact printers
Laser printers
Turnaround documents
Advantages/disadvantages
of printed output
Many people prefer to work with paper
Paper is portable
Printed output is expensive to purchase, print, store, and dispose of
Printed output is outdated quickly
Screen output
The screen is
the most familiar output device
Monitor
CRT (cathode ray tube)
LCD (liquid crystal display)
VDT (video display terminal)
Graphical output
allows various special effects and user-friendly features
Screen output
reflects immediate data changes
Other types of information delivery
Audio output
Automated facsimile
and faxback systems
E-mail
Links to Web
pages
Specialized
forms of output
Designing Printed Reports
Reports can be classified by content
Detail reports
Exception reports
Summary reports
Reports also can be classified by distribution
Internal reports
External reports
Detail reports
Provide the
most information
At least one
line of output is produced for each record processed
Detail reports
can be quite lengthy
Control-break reports
Use a control
field
Must be sorted
on the control field before printing
A control break
occurs when the control field value changes
Exception reports
Show only records
that meet a specific condition
Useful when
particular information is required
Special parameter
queries can be used to select only the records that meet specified conditions
Summary reports
Show only subtotals
and totals
Useful for upper-level
managers who do not require extensive detail
Internal reports
Distributed
within the organization
Usually printed
on stock paper
Blank, single ply, standard size
Less expensive
Can be used for many types of reports
External reports
Distributed
outside the organization
Might include
statements, invoices, or paychecks
Usually printed
on special forms
More expensive than stock paper
Paper must be changed for each report printing job
Multi-part forms must be separated or decollated
Special forms can use preprinted graphics and logos
Special applications,
such as checks, require special forms
Designing the report
Most reports
use graphical design
Choice of typefaces and scalable fonts
More design flexibility
Some reports
are character-based
Printed on high-speed impact printers
Require printer spacing charts for layout and design
Stock paper reports
Page heading
lines
Column heading
lines
Column heading
alignment
Spacing between
columns
Order of data
items on detail lines
Grouping detail
lines
Report footing
Improving a
report design
Documenting
a report design
Design Consistency
Special form reports
Can use printer
spacing charts to design
Placement of
preprinted graphics can be indicated
Functional and
aesthetic design principles are important
Field labels
should be short but descriptive
Avoid nonstandard
abbreviations
Order and placement
of printed fields should be logical
Totals should
be identified clearly
Report volume and time calculations
Accurate estimates
are necessary to
Determine whether printing capacity is adequate
Achieve efficient printing operations
Ensure timely delivery of finished reports
Provide reliable forecasts of paper and storage needs
Factors to consider
Types of printers
Print volume calculations
Print-time calculations
A KEY QUESTION
The problem: users receive many reports, but
do not seem to read them.
The solution?
Designing Screen Output
Major advantage is timeliness
Screen output can be produced when and where
needed
Disadvantage - no tangible record
When would you use screen output?
Screen design considerations
Many print design
principles apply to screens
Screens also
need instructions and messages
Users require
immediate Help and feedback
Character-based
screens
Screen locations are plotted using columns and lines
Use screen display layout forms
Messages typically on top or bottom line
Graphical screens
Screen locations are plotted in inches or other units
More flexible designs are possible
Character output
High-resolution
monitors allow more flexibility
Display must
be clear and easy to read
Fonts and typefaces
must be chosen carefully
High-resolution
monitors allow more flexibility
Display must
be clear and easy to read
Fonts and typefaces
must be chosen carefully
Screens vs.
printed output
Information might need redesign for smaller screen
Multiple screens might be necessary
Columnar or tabular designs are possible
Graphical output
Graphical displays
can be very effective
Many formats
are possible
Pie charts
Maps
Bar charts
Area charts
Scatter diagrams
Use descriptive
titles, label each axis, and include a legend
Special effects
Character-based
systems can use special effects
High brightness
Blinking
Reverse video
Use of different colors for emphasis
Graphical environment
provides options
Command buttons
Boxes and borders
Unlimited use of color
Custom menus, icons, and multiple windows
Designing Other Outputs
Output to tapes and disks
In an integrated
environment, data transfer is handled by interactive network design
In other cases,
data transfer uses tapes or disks
Output from one program can be input to another
An output file format is a data structure that can be understood by another
program or system
Tape or disk output design must calculate file volume
Other output media
Format and contents
depend on the output device and its requirements
Various output
options exist
Plotter output
Series of commands is formatted for the specific plotter being used
Computer output microfilm (COM)
Output is recorded as images on roll or sheet film
Data scanned/stored in digital form
Output Control
Output integrity
Ensure output
is correct, complete, & secure
Include appropriate
titles and dates on reports
Number pages
consecutively
Identify the
end of each report
Print/reconcile
control totals/record counts
Review error
reports for possible causes
Create error
file to flag uncorrected/reentered records
Output security
Protects privacy
rights and proprietary data
Important tasks
to carry out
Control the number of report copies
Distribute reports only to authorized users
Store sensitive reports in secure areas
Label all pages of confidential reports
Burn/shred sensitive reports & other output
Inventory blank checks regularly
Store signature forms securely
Automated Design Tools
Report generators
Included in
CASE tools & database programs
Powerful, easy-to-use
features
Enter constant information (titles/headings)
Specify a print position for each item
Use field sizes from data dictionary to create a design
Produce a report definition
Creates program code that can be modified
Screen generators
Similar to report
generators
Create displays
using onscreen layout tools
Completing the report and screen designs
Ensure consistency
with data dictionary
Automate routine
design tasks
Produces rapid
results
Does not guarantee
good design
Still must know and apply effective design to produce reports and screens
that satisfy user requirements
Key Points And Objectives
1. Prototyping is an information-gathering
technique useful for supplementing the traditional systems
development life cycle.
2. Prototypes are useful in seeking user reactions, suggestions, innovations, and revision plans.
3. There are four conceptions of prototypes:
I. patched-up prototypes
II. nonworking scale models
III. first full-
scale models
IV. prototypes which contain only some
of the essential system features.
4. One advantage of prototyping
is the potential for changing the system early in its development.
A
second advantage is the opportunity to stop
development on an unworkable system. A third
advantage is the possibility of developing
a system that closely addresses users' needs and
expectations.
5. One disadvantage of prototyping
is that managing the prototyping process is difficult because of
its
rapid, iterative nature. A second disadvantage
is that incomplete prototypes may be regarded as
complete systems.
6. Systems analysts must work systematically
to elicit and evaluate users' reactions to the prototype.
There are three ways the user is involved:
I. experimenting with the prototype
II. giving open reactions to the prototype
III.
suggesting additions to and/or deletions from the prototype.
Key Points And Objectives
1. In order to prepare the systems
proposal in an effective way, systems analysts must use a systematic
approach to identify hardware and software
needs - ascertaining hardware and software needs,
identifying and forecasting costs and benefits,
comparing costs and benefits, and choosing the most
appropriate alternative.
2. In ascertaining hardware and
software needs, systems analysts may take the following steps. First,
inventory computer hardware already available
in the organization. Second, estimate both current
and projected workload for the system.
Then, evaluate the performance of hardware and software
using some predetermined criteria. Next,
choose the vendor according to the evaluation. Finally,
acquire the hardware and software from the
selected vendor.
3. When inventorying computer hardware,
systems analysts should check such items as type of
equipment, status equipment operation, estimated
age of equipment, projected life of equipment,
physical location of equipment, department
or person responsible for equipment, and financial
arrangement for equipment.
4. When evaluating hardware, the
involved persons, including management, users, and systems
analysts, should take the following criteria
into consideration: time required for average transactions
(including time for input and output), total
volume capacity of the system, idle time of the central
processing unit, and size of memory provided.
5. When evaluating hardware vendors,
the selection committee needs to consider hardware support,
software support, installation and training
support, and maintenance support as well as the
performance of the hardware.
6. When evaluating software packages,
the selection committee needs to take the following factors into
consideration as well as total dollar amount
to purchase them. They are: performance effectiveness,
performance efficiency, ease of use, flexibility,
quality of documentation, and manufacturer support.
7. Systems analysts may forecast
costs and benefits of a prospective system through analysis of time
series data including linear trend, seasonal
trend, and cyclical trend, and estimation of trends using
graphical judgment, the method of least squares,
and the moving average method.
8. Systems analysts should take
tangible costs, intangible costs, tangible benefits, and intangible
benefits into consideration to identify cost
and benefits of a prospective system.
9. To select the best alternative,
systems analysts should compare costs and benefits of the prospective
alternatives. Break-even analysis, payback,
cash-flow analysis, and present value method are the
most popular techniques for this purpose.
10. To select the best method for comparing
alternatives, systems analysts may refer to the following
guidelines:
A. Use break-even analysis if the
project needs to be justified in terms of cost, not benefits.
B. Use payback when the improved
tangible benefits form a convincing argument for the
proposed system.
C. Use cash-flow analysis
when the project is expensive, relative to the size of the company.
D. Use present value when the
payback period is long.
Key Points And Objectives
1. Through the use of effectively
organizing the content, writing in a professional style, and
orally presenting the proposal in an informative
way, the analyst can create a successful
systems proposal.
2. When preparing a systems proposal,
systems analysts should arrange the following items in
order:
A. Cover letter.
B. Title page of project.
C. Table of contents.
D. Executive summary (including
recommendation).
E. Outline of systems study with
appropriate documentation.
F. Detailed results of the systems
study.
G. Systems alternatives (3 or
4 possible solutions).
H. Systems analysts' recommendations.
I. Summary.
J. Appendices (assorted documentation,
summary of phases, correspondence, etc.).
3. When writing a systems proposal,
systems analysts need to keep references to a minimum
and should not use footnotes. Also,
systems analysts need to use examples, illustrations,
diagrams, tables, figures, and graphs to support
main points of the proposal, where
appropriate.
4. Some guidelines to use tables effectively are:
A. Type only one table per page
and integrate it into the body of the proposal.
B. Try to fit the entire table
vertically on a single page if possible.
C. Number and title the table
at the top of the page. Make the title descriptive and
meaningful.
D. Label each row and column.
E. Use a boxed table if room permits.
F. Use an asterisk if necessary
to explain detailed information contained in the table.
5. Some guidelines to use graphs effectively are:
A. Draw only one graph to a page
unless you want to make a critical comparison
between graphs.
B. Integrate the graph into the
body of the proposal.
C. Give the graph a sequential
figure number and a meaningful title.
D. Label each axis, and any lines,
columns, bars, and pieces of the pie on the graph.
E. Include a key to indicate differently
colored lines, shaded bars, or crosshatched areas.
6. Some guidelines to use figures effectively are:
A. Whenever possible integrate
the figure into the body of the proposal itself.
B. Always introduce figures in
the text before they appear.
C. Always interpret figures in
words, never leave them to stand on their own.
D. Title all figures, label each
axis, provide legends where necessary.
E. Use more than one figure if
necessary, so that the visual does not become cluttered.
7. To make presentations more persuasive,
the systems analysts may use white space, headings
and subheadings, effective page numbering
style and position, relevant references and
appendices.
8. After finishing the preparation
of systems proposals, systems analysts need to consider the
following items to present the systems proposal
effectively. They are:
A. Organizing the presentation
by deciding the format, structure, sequence, visual
devices, and other tools including PCs.
B. How to deliver the oral presentation
effectively.
9. Presentation software is available
that allows the analyst to use a microcomputer for a slide
show. The presentation may be enhanced
by the use of:
A. Clip art.
B. Video clips.
C. Sound.
D. Easily adding or deleting presentation
slides for the audience and length of time
available.
10. Guidelines for the use of presentation software are:
A. Use software templates.
B. Use a combination of graphics
and text to communicate.
C. Keep each slide clean and simple.
D. Use color in a meaningful way.
E. Use clip art to enhance the
text and add humor.
F. Use sound to reinforce the
presentation.
G. Use a multimedia approach.
11. When delivering the oral presentation,
systems analysts need to keep the following facts in
mind. They are:
A. Project loudly enough so that
the audience can hear you.
B. Look at each person in the
audience as you speak.
C. Make visuals large enough so
that the audience can see them.
D. Use gestures that are natural
to your conversational style.
E. Introduce and conclude your
talk confidently.
12. To overcome anxiety and nervousness,
systems analysts may take preventive actions such
as:
A. Be yourself
B. Be prepared
C. Speak naturally
D. Breathe deeply before your
presentation.