Topic 1: System Fundamentals
Considerations for changing a new system:
1. The extent of the change (are we completely changing it so that the interface has
different features or are we simply just updating the system)
2. The limitations of a new system
3. The context in which the system will be used (organizational issues or change in user
roles)
Ex: a school changes the software that records grades.
What are the difficulties in changing software systems:
- Users don’t like the change.
- Some features may be omitted or left out.
- Old systems may be faster (cost in terms of performance).
- Incompatibility with other systems.
- Data loss (data migration can result in loss of data).
- Expensive (system may be created custom made)
4 ways of change:
1. Direct changeover: Stop running old systems and use new systems immediately.
Pros: New system is available immediately- no waiting out, changeover shift.
Cons: No backup incase of failure, no redundancy or protection in place.
2. Parallel: Old and new system running concurrently with data being entered to both
systems.
Pros: If the new system fails you can continue using the old system (backup), output from
both systems can be used to verify if output from the new system works correctly.
Cons: It is expensive having to run both systems at the same time
3. Pilot system: A system is tested within a small part of the system, it is refined and
then introduced into the rest of the system (expands).
Pros: All features are tested before adoption by the whole organization (if the new system
fails only a small part of the system suffers), staff who are part of the pilot can train others
Cons: no backup incase of failure.
4. Phase transition: Features of the new software are introduced in phases, feature by
feature, while the old system is slowly phased out.
Pros: Allows users to get used to the new system, training can be done in stages instead of
one big block making it easier for staff to get acquitted.
Cons: There is no backup.
★ Data migration: moving data from one system to another
- Can be a huge process depending on sizes of the systems.
- Necessary when transitioning to new system
→ Possible issues:
1. Incompatible file formats
● Different systems might use different versions of same software- different file formats
● Data simply stored in different file formats because of different softwares
2. Data structure differences
, ● Ex: Data stored in arrays in memory in one software system whereas it is stored as
linked lists in another system.
→ Would need to write an algorithm to take data from one data structure and
transfer it to another data structure that can easily be read and processed.
● Ex: Data stored in tables in one system and spreadsheets in another.
3. Validation rules
→ Rules that are put in place to make sure that the data being entered by the user is valid
and fits certain parameters (ex: not negative, less than 100, is only integers)
● Different rules for what constitutes valid data
● One system may be much less strict than another making data unacceptable for
migration.
4. Incomplete data transfers
● When a process is interrupted from some reason
● Not all the data is moved to the new system
● Data may be lost
5. Different data/ currency/ character conventions
● Moving from a US built software system to a system built in the UK.
● Dates in different order/ different currencies used in the different systems/ different
languages/characters.
What is a legacy system?
- Old technology, computer systems, or applications that are no longer supported by
their parent companies or available purchase.
- Modernization is expensive and time consuming
Local Versus Remote software (SAAS- Software as a Service)
- Local- Runs on your computer and is not tethered to the internet (notepad, adobe,
photoshop)
- Remote- Accessed through a web browser (google docs)
Traditional Software SaaS Software
● One-time fee ● Subscription fee
● Use on one computer ● Use on any computer via internet
● Not available on mobile devices ● Available on many mobile devices
● Installment required ● Installment not required
● Some updates are automatic ● All updates are automatic
● Less likely has supplemental apps ● Most likely has supplemental apps
● A new version requires a new ● Users are always working from the
purchase latest software version
● Mobile synchronization requires ● Mobile synchronization requires
additional software and often costs. additional software often free
★ Benefits of saas: Employee mobility, cost savings, scalability (any number of users
can use a piece of saas software as long as there is a service infrastructure to support
this), fewer support staff being all of the support is being handled by the third party
company providing the SaaS software, pay as you go, and easier maintenance.
Considerations for changing a new system:
1. The extent of the change (are we completely changing it so that the interface has
different features or are we simply just updating the system)
2. The limitations of a new system
3. The context in which the system will be used (organizational issues or change in user
roles)
Ex: a school changes the software that records grades.
What are the difficulties in changing software systems:
- Users don’t like the change.
- Some features may be omitted or left out.
- Old systems may be faster (cost in terms of performance).
- Incompatibility with other systems.
- Data loss (data migration can result in loss of data).
- Expensive (system may be created custom made)
4 ways of change:
1. Direct changeover: Stop running old systems and use new systems immediately.
Pros: New system is available immediately- no waiting out, changeover shift.
Cons: No backup incase of failure, no redundancy or protection in place.
2. Parallel: Old and new system running concurrently with data being entered to both
systems.
Pros: If the new system fails you can continue using the old system (backup), output from
both systems can be used to verify if output from the new system works correctly.
Cons: It is expensive having to run both systems at the same time
3. Pilot system: A system is tested within a small part of the system, it is refined and
then introduced into the rest of the system (expands).
Pros: All features are tested before adoption by the whole organization (if the new system
fails only a small part of the system suffers), staff who are part of the pilot can train others
Cons: no backup incase of failure.
4. Phase transition: Features of the new software are introduced in phases, feature by
feature, while the old system is slowly phased out.
Pros: Allows users to get used to the new system, training can be done in stages instead of
one big block making it easier for staff to get acquitted.
Cons: There is no backup.
★ Data migration: moving data from one system to another
- Can be a huge process depending on sizes of the systems.
- Necessary when transitioning to new system
→ Possible issues:
1. Incompatible file formats
● Different systems might use different versions of same software- different file formats
● Data simply stored in different file formats because of different softwares
2. Data structure differences
, ● Ex: Data stored in arrays in memory in one software system whereas it is stored as
linked lists in another system.
→ Would need to write an algorithm to take data from one data structure and
transfer it to another data structure that can easily be read and processed.
● Ex: Data stored in tables in one system and spreadsheets in another.
3. Validation rules
→ Rules that are put in place to make sure that the data being entered by the user is valid
and fits certain parameters (ex: not negative, less than 100, is only integers)
● Different rules for what constitutes valid data
● One system may be much less strict than another making data unacceptable for
migration.
4. Incomplete data transfers
● When a process is interrupted from some reason
● Not all the data is moved to the new system
● Data may be lost
5. Different data/ currency/ character conventions
● Moving from a US built software system to a system built in the UK.
● Dates in different order/ different currencies used in the different systems/ different
languages/characters.
What is a legacy system?
- Old technology, computer systems, or applications that are no longer supported by
their parent companies or available purchase.
- Modernization is expensive and time consuming
Local Versus Remote software (SAAS- Software as a Service)
- Local- Runs on your computer and is not tethered to the internet (notepad, adobe,
photoshop)
- Remote- Accessed through a web browser (google docs)
Traditional Software SaaS Software
● One-time fee ● Subscription fee
● Use on one computer ● Use on any computer via internet
● Not available on mobile devices ● Available on many mobile devices
● Installment required ● Installment not required
● Some updates are automatic ● All updates are automatic
● Less likely has supplemental apps ● Most likely has supplemental apps
● A new version requires a new ● Users are always working from the
purchase latest software version
● Mobile synchronization requires ● Mobile synchronization requires
additional software and often costs. additional software often free
★ Benefits of saas: Employee mobility, cost savings, scalability (any number of users
can use a piece of saas software as long as there is a service infrastructure to support
this), fewer support staff being all of the support is being handled by the third party
company providing the SaaS software, pay as you go, and easier maintenance.
