IB Computer Science - Exam 1 Review
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Direct Changeover
New System completely replaces old system in a short amount of time (ex. an entire law firm moves from one building to another in a day)
Advantages
Cheap, Easy
Efficient, short installation time
Available Immediately
Disadvantages
Compatibility Issues may arise
No recovery available
Employees may not like system
Parallel Changeover
New system started alongside old system and used with the same data (ex. 2 internet providers used at the same time)
Advantages
If new system fails, old system runs backups
Both systems may be compared to see if new system provides correct results
Disadvantages
Takes significantly longer to do so
Costly to keep both running
Pilot Changeover
New system tested on a small section alongside large-scale old system, once ironed out, new system will completely replace old system
Advantages
Cost-Effective
All features tested
If it fails, then it will only effect a small number of people
Disadvantages
Those in the pilot group will have a delay in work efficiency
The pilot group may approve of the new system, but others may not
Phase Changeover
New system introduced in phases, slowly replaces old system in parts (ex. changing computers in a large school. classroom by classroom each day)
Advantages
Allows people to get used to system
Training of staff done in stages
Disadvantages
100% implementation will take much longer
Types of Data Loss
Hardware/Systems malfunctions
Human Error
Software Corruption
Malicious Software (Viruses)
Natural Disasters
Ways to Prevent Data Loss
Updates - fix problems found by people to prevent software corruption by fixing code, usually free
Patches - small bits of code inserted into program for temporary fixes
Human Error Prevention - keep liquids and magnets away, use a backup power supply (UPS), clean computers, and keep it safe from theft
Removable Media - makes it easy to safely remove storage from computers to others
Offsite Storage - a backup process external to an organization which is a physical copy
Cloud Storage - backup stored on the internet which is done remotely
Failover System - constant capability to automatically switch to a reliable backup system when the primary server fails
Data Redundancy - same piece of data held in two separate places to offer extra layer of protection