Comp Sci Systems 2 Flashcards
Legacy System
An old technology or computer system
Legacy System Compatibility
Operating systems. data formats. hardware
Legacy System (lack of) replacement
Still work well. too costly to develop new system. users are comfortable
In House hosting
+Low ongoing costs. full control. all data is kept within the organization -High initial cost. technical skills required to maintain
Outsourced hosting
+Low initial cost. no technical skill required -High ongoing cost. loss of full control. security risk
Installation Processes
Parallel running. pilot running. phased conversion. direct changeover
Data migration
The process of moving data from one system to another. usually an older system to a newer one.
Data migration issues
Incompatible file formats. data structures. validation rules Incomplete data transfer international conventions on dates. currencies and character sets
Testing
Debugging. alpha testing. beta testing. black-box testing. white box testing. unit testing. system testing. acceptance testing. automated testing
Debugging
Ongoing. happens during development
Alpha testing
the first stage of testing. done by the programmers themselves
Beta Testing
Later testing. done by future users when the system is almost finalised
Black-box testing
testing what the system is supposed to do. from the point of view of the user. with no knowledge of how the program does what it does
White-box testing
testing the system from the point of view of the programmer. with full knowledge of how it does what it does
Unit testing
testing the modules or components of the system separately
System testing
Testing the system as a whole
Acceptance testing
The last testing phase once the system is delivered to the user
Automated testing
Using software to test software
Importance of user documentation
Installation. operation. troubleshooting. sample data and screens. easing transition from legacy systems
Methods of providing user documentation
Paper manuals. online manuals. interactive tutorials. dedicated support teams
Paper manuals
Dont need to be near a computer need multiple copies
Online manuals
Can make use of rich media Can search Always available
Interactive Tutorials
Makes the learning process more interesting
Dedicated support teams
can give accurate focused assistance increases salary bill
Methods of delivering user training
self-study. formal classes. online training. blogs. wikis. forums. FAQ’s. getting feedback from users
Self-study
Slow. boring and inauthentic
Formal classes
Make users feel more secure and involved.
Online training
Reduce travel costs. but can cause time zone issues
Causes of data loss
virus. malware. nautral disasters. hardware failure. user error. physical damage. power failure. back-ups are essential to prevent data loss
Consequences of data loss
Business activities may have to be suspended. damages the organization’s reputation. cost to replace data
How to prevent data loss
Back up. antivirus. failover and redundancy
Back up
removable media (USB). cheap simple to install. large capacity. easy to move offsite. Offsite: take back-ups in case of disasters Online: Always available. requires internet connection. possible security risk
Antivirus
Prevent malware from deleting/editing data
Failover and redundancy
Redundant system is a clone of an existing that is kept up-to-date in case the primary fails. Failover is the process of detecting a failure of the primary system and switching users to the redundant system.