Topic 1: System fundamentals Flashcards
Feasibility study
Analyses a project and its potential based on the TELOS criteria
Why do we need a new system?
Replace a system that is inefficient
No longer suitable for its purpose, redundant or out-dated.
To increase productivity, quality of the output or minimise costs
The new system should fix errors of the previous system.
Legacy system
Old method, technology, computer system, or application program. It may or may not be available for purchase any more.
Such a system may still be in use because its data cannot be converted to newer format or its apps cannot be upgraded. And if it is, it needs manteinance
Business merger
Combination of two or more entities, especially companies, into one.
Issues that can arise from business merger
Issues of software compatibility
Language differences
Time zone differences
Workforce cultural differences
Remote
Software distribution model in which a third-party provider hosts applications and makes them available to customers over the Internet.
Local
Software distribution model which is installed on the user’s computer system, either on a server on a local network, an isolated computer, or on a laptop.
Advantages of SaaS
Scalable solution:
Businesses simply adjust their monthly subscription as required.
Less expensive: Low initial cost and requires few investments of installation, maintenance and upgrading.
Reduction in staff workload: IT workers are liberated from on-premise hardware and
software tasks.
Variety: Wide range of desktop, portable and mobile devices support SaaS.
Safety: Applications and data reside in the cloud service of the provider’s data center.
Disadvantages of Saas
Data loss: Possible if a SaaS provider goes out of business.
Internet requirement: Performance of web based app, accessed by internet connection is low compared to software running on a local machine or local area network.
Parallel changeover and its pros/cons
The new system is started, but the old system is kept running alongside it. Data has to be entered into both systems.
V If the new system fails, the old systems runs a backup (no loss of productivity), outputs from the two systems can be compared to see if new one is running correctly
X Running two systems is costly in terms of time and money
Direct changeover and its pros/cons
Old system is stopped and new system is started.
V Minimal time and effort, new system is available immediately
X If the new system fails, there is no fall back
Pilot changeover and its pros/cons
The new system is piloted (tested) with a small subset of the organisation. Once it is running correctly and all bugs have been ironed out, it is implemented across the whole organisation.
V All features are fully trialled; if the new system fails, only a small part of the organisation suffers; staff who were part of the pilot can train other staff.
X For the subset of users in the pilot group, there is no backup if the new system fails.
Phased changeover and its pros/cons
The new system is introduced in steps as parts of the old systems are gradually replaced with the new system.
V Allows people to get used to the new system; training of staff can be done in stages
X If the new system fails, there is no fall back for that part of the system.
Data migration
Refers to the transfer of data between different formats, storage types or computer systems.
Problems arised from data migration
Incompatible file formats: Same piece of software might have different versions
Data structure differences: Moving data from a table to a flat file, or from an array to a linked list, might cause a lot of problems.
Validation rules: Due to rules applied to inputs. data can be rejected and lost.
Incomplete data transfers: Data may be lost or not transferred due to an incomplete data transfer because it was interrupted or errors during the process.
International conventions: Problems with dates, currencies & character sets.
Beta testing
Performed by a selected group of clients or end users who are not employees of the organization. Performed at client location.
Alpha testing
Performed by selected group of testers who are usually internal employees of the organisation. It’s performed at developers site.
Dry pen testing
Conducted using pen and paper by the programmer, who mentally runs the algorithm.
Unit testing
Individual parts of the system are tested separately
Integration testing
The entire system is tested to see if all elements work correctly together
Debugging
Systematic process of finding and correcting errors in a program.
User acceptance testing
Testing any new/updated system with its end users to see if it meets their expectation, which is very important.
Validation
Process of evaluating whether the data input meets identified specifications.
Verification
Verification is the process of ensuring that input is the same as the original source data.
User documentation
Any document that explains how to use the features and functions of a system to its end-users. For example, books, PDFs, websites, videos, etc.
Online support and pros/cons
Special web service hosted by the system’s developer to provide user documentation.
V More extensive
- They get continuously revised by the systems developer to deal with the problems occurring most often (FAQs)
- They often provide an option for live support, talking to a real human operator if a problem arises which the user documentation has no answer to
- They often have search capabilities built-in so that users can easily search through them
X They are useless if users have no internet connection
- Live support does not work quite well with users unfamiliar with computers when they have to explain their problem (“I clicked ‘that’ button and then
something happened!”)
Printed manuals and pros/cons
Manuals printed on paper and supplied together with the system.
V They can be read before starting to work with the new system.
- Always available
- Gives help installing the system
X Can be lost or limited in number
- Often limited to a little booklet supplying little info apart from how to install the system.
- Not updated every time the system is updated
Integrated user assistance and pros/cons
Files supplied together with the system. They can usually be called up with a button in the system (Help button). Also when you move the mouse over an icon, there is a box with information.
V Accessible at any time when using the program
– Give general instructions on how to use the system
– Give general instructions on how to solve some major errors
X They don’t give any help when installing the solution
– They often only deal with very general errors
– They often lack a search capability, you have to look to find help for your problem.
Self instruction and pros/cons
Users can learn how to use a new system on their own, provided they have the right material to learn from. It can take the form of reading a manual or watching a tutorial.
V No tuition fee
- Users can study whenever they want.
X Lack of guidance or teacher support
- Final result depends on the motivation of the user
- Things ignored
Formal classes and pros/cons
Users sitting in a classroom listening to an instructor who shows and explains how to use the system. This type of training is useful to train large amounts of staff.
V Structured learning environment
- Expert on hand to answer questions
- Curriculum designed to teach all aspects, including ones that might be misunderstood.
X If class is too big, there is little time to deal with individual problems and questions. - Expensive
Remote/Online training
An instructor training one user or a small group of users by some kind of remote connection.
V Structured learning environment
- Expert on hand to answer questions
- Curriculum designed to teach all aspects, including ones that might be misunderstood.
- Flexible locations
X Expensive
– Can feel ‘remote’ with no quick ‘hands on’
– Has to be computer-based
Data Loss
Error condition in information systems in which information is destroyed by failures or neglect in storage, transmission, or processing.
Causes of data loss
Accidental deletion Administrative error Closing program without saving Computer viruses Data or firmware corruption Natural disasters Outsiders wanting to delete it Physical damage of the storage device Power failure
Solutions for data loss
Regular backups Store data in more than one locations Authentication methods Need for a UPS Firewall Antivirus software File recovery software Hard copies Online backup
Failover program
Switching to a standby computer server upon the failure of the system, used to reduce the impact on users.
Patches
Set of changes to a computer program designed and used by software companies to update, fix bugs and vulnerabilities, or improve it.
Upgrades
An upgrade mostly includes important changes to the GUI and a variety of new features and options which are not in the existing version of a software or operating system. Most cases upgrades need to be bought.
Updates
Updates improve a product in a minor way by adding new functionalities or fixing known bugs. Are free.
Release
A product release is the process of launching a new product for a specific market or user base.
Are final, working versions of software applications. They have already gone through alpha and beta testing.
Computer hardware
The physical elements of a computer.
Computer Software
A series of instructions that can be understood by a CPU and guide it to perform specific operations. It include the programs and other operating information used by a computer.
Computer Network
A set of computer systems interconnected between them. They share resources and data.
Human Resources
People who are used or could be used in an organization.
Server
may be a program or a computer that provides services requested by clients connected over a network while a client is an average computer.
DNS Server
Domain Name System Server attributes names to network addresses and therefore resolves names by assigning them to the appropriate network entity. It allows you to type names into the address bar of your web browser. Is a protocol within the set of the TCP/IP protocol suite.
Firewall
Hardware or software network infrastructure that controls data flow access among network entities. It offers protection and limit access to a network.
Client-server
Refers to a software network architecture system where client request information and servers perform tasks in order to provide the information. The main difference between server and client is that servers share their resources while clients don’t.
Client in networking world
Receives data via the network, whereas the server has saved data on it and offers it to clients.
Stakeholder
Individuals, teams, groups or organizations that have an interest in the realization of a project or might be affected by the outcome of a project. Usually pays for the project.
End user
Person or group that is going to use the product.
Obtaining info: Interviews
Is a direct face to face procedure that focuses on obtaining reliable and valid data via asking questions. Can be structured or unstructures.
Obtaining info: Direct observation
Involves spending time watching someone or a group using the product. Study that can show how procedures and processes work and how could they be more efficient.
Online processing
Data is executed at the same time. There’s no limit time for input and output.
Real-time processing
Very fast and quick respondent systems. Requires quick transaction and characterized by supplying immediate response. Usually uses sensors. Difficult to implement.
Batch processing
Efficient way of processing large volumes of data all at once. Works with packets. May require dedicated staff to handle issues.
Modular design
Process of designing system modules individually and then combining the modules to form a solution to an overall problem.
Prototype
Either a working or non-working preliminary version of the final system that is used as part of the design phase that is used to demonstrate how the final product will work
Purposes of a prototype
- Attracts the attention of the client
- Provides just enough of the concept for the investors to decide if they want to fund the full product or not
- Encourages active participation
- Gives an idea of the final product
- Helps identifying the problems with the efficiency or the design
- Increases system development speed
Iteration
Refers to the repetition of a set of instructions for a specific number of times or until the operations yield a desired result.
Usability
Potential of a product, app or website to accomplish user goals.
Accesibility
Refers to the potential of a service, product, device or environment to serve and meet the needs of as many individuals as possible.
Ergonomics
Refers to the design of safe and comfortable products, systems or processes, specifically for people.
Componenrts of usability
Readability Effectiveness Complexity Efficiency Learnability Error Satisfaction Memorability
Server
Software or hardware device that provides services for other programs or devices in the network.
Shares resources and provides sevices.
Can connect to other devices using LAN or Internet.
Host
Computer or device that connects to the network.
Shares and consumes resources.
Can connect to other devices using Internet.
Steps of data migration
Extract, Transform, Load, Validate
Peripheral device
Auxiliary device that extends capabilities of the computer.
