5e- Installation +/-

5e- Installation +/-

1. Direct (Plunge)

   • Advantages
     • O- Cheap to implement
     • O- No duplication of work
       • O- No loss of data integrity
     • O- Quick changeover
     • O- Systems don't need to been compatible
     • O- Can be down at off peak times e.g. bank holidays
   • Disadvantages
     • X- Any problems could cause system failure
       • No old system to go back to
     • X- Training for entire organisation has to be done in advance is everyone start the new system at once
       • X- Can take a long time for large organisation, meaning people may forget their training

2. Parallel

   • Advantages
     • O- Can revert to old system if new system fails
     • O- New system's accuracy can be well compared to the old system
   • Disadvantages
     • X- Extra staff needed for duplicated data entry
       • X- Extra equipment and space may also be needed
     • X- Data integrity may be compromised

3. Phased

   • Advantages
     • O- Lower risk of failure
       • O- Problem will only affect one part of the system and old system continues to work as usual
     • O- Errors can be identified by module and corrected with little effect
     • O- Training can take place one module at a time
   • Disadvantages
     • X- Can take long time
     • X- Have to wait and check module is working each time a new one is introduced.
     • X- Using two systems may confuse workers
       • X- Have to remembers which system to use for which task
     • X- Have to share data between both systems
       • X- Difficult if systems are incompatible

4. Pilot

   • Advantages
     • O- Only one group of people affected by failure
     • O- Errors found in pilot stage can be corrected before going live
     • O- Can slowly add more people to new system to train over a long time
       • O- Pilot group can be used as trainers
   • Disadvantages
     • X- Can slow changeover process
     • X- Pilot group feel like guinea pigs having to work with error prone version
     • X- Compatibility issues may make task less efficient for pilot group