6 Stages of the Traditional
Systems Life Cycle
 project definition
 systems study
 design
 programming
 installation
 post-implementation
4 Steps in Prototyping
 identify preliminary requirements
 develop a working prototype
 use the prototype; and refine
 enhance the prototype
Software Package-Based
Development
 Use the software vendor's response to a
Request for Proposal (RFP) about package
features
End-User/Fourth-Generation
Development Tools:
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personal computer tools
query languages
graphics languages
report generators
application generators
very high-level programming languages
application software packages
Outsourcing
Outsourcing is the process of handing
over some or all of a function to an
external vendor.
Information Systems Threats
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disaster, such as fire or electrical failure
hardware malfunction
software errors
user errors
computer crime
computer abuse
Computer Crime
– monetary theft
– theft of services, information, or computer
programs
– alteration of data
– damage to software
– trespassing
IS General Controls
Hardware
Restrict access
Preventive maintenance
Software
Activity logs
Restrict access
Data security
Password
Restrict access
Encryption
Operations
Procedure standardization
Backup & recovery
Systems development Management review & audit
Documentation
Management
Formal written policies & procedure
Division of labor
Supervision
Accountability
IS Application Controls
Input
Authorization/validation
Control totals, e.g., record counts
Edit checks, e.g, format & existence check
Error correction
Processing Edit checks, e.g., check digit
Control totals, e.g., hash totals
Output
Control totals
User feedback
Authorization
Information Systems Security
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Data security
Hardware security
Network security
Recovery plan
Information Systems Quality
• Using development methodology
• Using quality measurements, e.g., response
time, # of bugs per 1000 lines of code
• Using programming standards
• Using testing standards
• Using development tools, e.g, CASE
• Using quality audits