CHAPTER 1 - SYSTEM FUNDAMENTALS Flashcards
(83 cards)
System life cycle
The stages through which the development of a new system passes through
5 stages of system life cycle
Analysis, Design, Implementation, Operation, Maintenance
Why is new system created
To replace inefficient old system, fix default/defects, increase quality of output/productivity of the system
Requirements needed for a new system
Internet, RAM, operating system, hardware, software
Limitation of new system
- end users not being able to use the system properly
- data migration is time consuming
- memory issues and data clashes when system is developed/tested
- maintenance is costly overtime
Potential organizational issues in planning of a new system
- lack of attention to required training
- lack of attention to organizational issues
- lack of stakeholder and end-user participation
Whats a feasibility study
study that evaluates and analyzes a project and its potential based on TELOS criteria: Technical, Economical, Legal, Operation and Scheduling
Planning
process of thinking about various details and organizing the activities required to achieve the desired goal
Whats TELOS criteria
Technical: Is existing technology appropriate to implement proposed system
Economical: Is it cost-effective
Legal: Is it against any laws/regulations
Operational: Is existing organizational practices sufficient to maintain and operate system
Scheduling: How long will we wait
What is change management
Involves various parameters and is the process of shifting existing individuals, teams and departments from an existing to desired state; goal is to maximise benefits and minimize negative impacts of the change on individuals
What is a legacy system
Old technology, hardware or computer system
Why are legacy systems still used
- Data cannot be converted to newer formats/applications cannot be upgraded
- System provides users needs even if newer systems exists
Outline one problem of maintaining legacy systems
Continuous patching, updating and upgrading of the old system to look out for any bugs/errors
4 strategies to integration
- Replace both information systems with a new one (high initial cost)
- Keep both information systems and develop them to have the same functionality (high maintenance cost)
- Select one company’s computer system and discard the other (policy problems)
- Select best info system from each company and combine them (workers may have difficulties working with a system from another company)
Software incompatibility
a situation where 2 different software systems cannot operate cooperatively/individually in a same computer or different computer linked by a LAN/WAN (network)
SaaS “Software as a Service”
a contemporary delivery method that allows software and data to be hosted & managed centrally on a remote datacenter.
Example: Powerschool/Netflix; basically just a software that offers a service
Features of SaaS
- Subscription: users have to pay to access services provided
- Uses a multi-tenancy model: single software and its supporting infrastructure can serve multiple customers
- Uses cloud service to store customer data (which reduces data loss risks)
Limitations to SaaS
- Possible data loss if SaaS provider goes out of business
- Involvement of a third party i.e. SaaS provider which risks user data privacy
- Uncertainty of data’s location: customers have lower access to their personal data; usually stored away in datacenter
- Risk of identity theft: the providers often require credit card payments for subscription; may not provide better identity management security/poor firewall
- Connectivity requirement: SaaS model is based on web delivery, if internet service fails, loses access to software data
- Access management: if design of the access control system is inefficient, a single act of accessing the cloud service can expose confidential data
Distinguish between Phased and Direct changeover
Phased conversion method is when the new system is implemented/introduced per module to the whole company. If the particular program/module is proven satisfactory, another module will be introduced until the system is introduced completely. With this approach, the training period is extended and the adoption of the new system takes longer since it is implemented separately at different times. On the other hand, direct changeover is very risky since the company replaces their old system with a new one immediately. With this approach, all users require proper training before the switch takes place, in order to use the new information system efficiently.
Direct/Big Bang changeover
instant from old to new
Parallel changeover
old and new is run side by side; only when output of new is proven satisfactory then the old system is terminated
Pilot changeover
the whole system is introduced to one branch/department of the company and its performance accessed before being introduced elsewhere in the company
Phased changeover
the new system is introduced per module to the whole company, only when its proves satisfactory then the next part is introduced - until the old system is fully replaced
Data migration
transfer data between different formats, storage types, computer systems; It usually takes place when a business changes, upgrades, or merges its computer systems