IB Computer Science - Topic 1

System

The complete set of components that work together to carry out a particular function. These include hardware, software, communications and people.

Feedback Loop

Allows outputs to be fed back into a system as inputs to allow for adjustment of a process.

Strategic Issues for a New System

Goals set by companies that a System will help them achieve

Data Security Issues for a New System

Data can be valuable (as an asset) or a liability (if lost).

Dependency Issues for a New System

Reliance on a single component in a System without backup

Change Management

An approach to transitioning individuals, teams, and organisations to a desired future System.

Legacy systems

Refers to outdated computer systems, programming languages or application software that are used instead of available upgraded versions.

Compatibility Issues

These occur when elements in a System are not designed to work together and require extra elements to translate between them.

Local Installation

Software/Data runs on hardware operated by the owner

Remote (cloud) Installation

Software/Data runs on shared hardware operated by a third party

Software as a Service (SaaS)

A software delivery method that provides access to software remotely as a web-based service.

Direct Change Over

The old system is stopped completely, and the new system is started. All of the data that used to be input into the old system now goes into the new one.

Parallel Changeover

The new system is started, but the old system is kept running in parallel for a while. All of the data that is input into the old system is also input into the new one. Eventually, the old system will be stopped, but only when the new system has been proven to work.

Phased Changeover

The new system is introduced in phases, gradually replacing parts of the old system until the new system takes over.

Pilot Running

One department of the business is given full implementation of the new system, similar to a 'trial version' of the system.

Data Migration

The process of importing legacy data to a new system.

Data Validation

The process of ensuring that a program operates on clean, correct, and useful data.

User Acceptance Testing (UAT)

Actual software users test the software to make sure it can handle required tasks in real world scenarios, according to specifications.

Alpha Testing

A group of programmers within the organisation examine early versions to see how the system performs. It is conducted when the software may still be unstable or has incomplete data functionality.

Beta Testing

A small subset of actual users adopt the new system for feedback purposes. Is conducted when the software is close to being ready for release and few errors are expected.

Automated Testing / Testbenches

Used when there are tests that can't be accomplished by manual testing because they would consume too much time and resources. It is when another software is used to check the performance of the software

User Documentation

Information included with software that delivers instructions on how to properly use a program for its intended purpose.

Tutorials

Users are guided through a process one step at a time. It is not always practical to create a complete one.

Help Files

This is a file attached to the program which contains the documentation organised by topic. Its consistent availability is its main advantage.

Online Documentation

This would require an internet connection in order to access the documentation. They can be updated in real time.

Printed Manual

This cannot be directly accessed through a computer, and if the physical copy is lost, they would lose access to the documentation. Things cannot be automatically searched.

Embedded Assistance

Many systems will now come with user documentation such as tooltips and dynamic page content within the system itself.

Hardware

All the physical parts that make up a computer, such as the motherboard, CPU, RAM, and power supply.

Peripherals

External hardware components that exchange information and can be easily installed and swapped (eg, keyboard, monitor, mouse, external hard drive)

Software

An organised collection of computer data and instructions, that can construct a computer to perform specific tasks.

Network

A group of two or more computer systems linked together via a wired or wireless communication medium

Stakeholders

A person, group, or organisation that is actively involved in a project, is affected by its outcome, or can influence its outcome.

Interviews

In-depth data collection through consultation of different stakeholders.

Questionnaires

A larger process of data collection from a wide range of stakeholders, though less flexibility and depth than an interview.

Existing Literature

Used to compare the system requirements and functionality with other turn-key systems.

Observations

People working with the existing system to note its functionality and how end users interact with the system.

System Development Life-Cycle (SDLC)

Composed of a number of clearly defined and distinct work phases that are used by system developers to iteratively plan for, design, build, and test systems

Requirement Analysis Phase

Defining criteria for success.

Gathering information.

Defining scope.

Defining inputs and outputs.

Analysis and Design Phase

This is where data models, prototype designs and testing plans are developed.

Implementation Phase

The process of creating the system. This is the coding phase.

Testing and Installation

This is where the tests planned during the design phase are applied to check that the system works correctly.

Evolution and Maintenance Phase

Small changes like patches are applied. Larger changes caused by internal or external factors might redefine the requirements of a system.

Prototype

A simple version of a system produced during the design stage. Its purpose is to show the user an interface and to give some indication of how the system is expected to work. It allows the user to propose changes at the design stage.

Usability

Is a measure of how easy it is to use a product to perform prescribed tasks. It focuses on the ease of use and learnability of human interactions with the system. The user, not the system, is put at the centre of the process. Comprised of Accessibility and Ergonomics.

Ergonomics

The physical relationship between people and the system they interact with.

Accessibility

The availability of a system to all people, regardless of disability or severity of impairment.

Iteration

the repetition of the design cycle in order to develop systems

Debugging

identifying and removing errors from computer hardware and software

Manual Updates

when an end user or administrator runs patches or reinstalls software on a local machine

automatic updates

when software collects and installs updates from a remote service without user interaction

Operating system

help people interact with the computer system and manage how the hardware, programs and data interact

Client

a computer accessing resources hosted by another computer/the server

Server

a computer hosting resources to be shared across the network