IB CS Yr 1: Topic 1: System Design 1.2

Computer hardware

physical elements of a computer

Software

instructions understood by CPU

Peripheral device

any auxilary device that can communicate/work with a computer. Not essential or core part

Computer network

set of computer systems that are interconnected

Human resources

people who are used in an organization, business, or economy

Dumb terminal

depends entirely on the single connected computer for anything related to data

Thin client

low performance terminal, heavily but not entirely dependent on its connected server

client

Recieves data via network

Server

has saved data and offers it to clients

Email server

manages flow of email, checks addresses, allows users email access

Router

networking device that accepts data packets and redistributes them across networks

Domain name system server

attributes names to network addresses and therefore resolves names by assigning them to the appropriate network entity. (finds websites through search bar)

Firewall

hardware or software network structure that controls data flow access among network entities. Offers protection and limits access to a network.

Client server

clients request info and servers perform tasks in order to provide info

servers vs. clients

servers share data, while clients receive/do NOT share

Reliability

how well an IT system functions

Integrity

protecting the completeness and accuracy of data

Inconsistency

problems that arise from duplicated data, causing inconsistency when one version is updated and the other is not

Security

protect hardware, software, peripherals, computer networks from unauthorized access

Authenticity

person proving their identity for access

Privacy

control how and to what extent data is used and disseminated to others

Anonymity

privacy becomes this when one’s identity is concealed for the purpose of harm

Intellectual property

copywrite laws protect this from being stolen

Surveillance

using IT to monitor individuals/groups with or without their knowledge (privacy issue)

Globalization and Cultural Diversity

diminish importance of real world boundaries while accelerating the spread of news. Traditional values may diminish over time.

IT policies

enforce correct use of technology

Standards and protocols

predefined technical rules and conventions that developers of hardware/software should follow. Allows for compatibility

Digital citizenship

appropriate behaviors in the digital world

Stakeholder

people with an interest in the realization of a project or may be affected by the outcome of a project

End-user

person who uses the product

Interview

face-to-face, obtain info through verbal response

Questionnaires

carefully constructed questions to elicit unambiguous responses

Direct observation

spend time in the facility to observe how it functions

Literature search

reading various resources to find info on a topic

Examining current system

detailed examinations of current system

Examining competing products

analysis of competitive factors, benefits, vulnerabilities, characteristics, design. A successful IT system should include a competitive advantage

Modern information

• increase client trust

• preserve brand strength

• preserve organization reputation

• maintain corporate resiliency

• enhance organizational piece

Online processing (interactive)

data processing performed by a single processor through the use of equipment that it controls. ex. airline reservation

Real-time processing

data processing performed on-the-fly, generated data influences the process taking place. ex. aircraft control

Batch processing

processing performed on data that has been composed and processed as a single unit. ex. payroll

System flowchart

constructed during analysis activities, represent computer programs, files, databases, manual processes, etc. Only way to refer to hardware.

Data flow diagram

shows how data moves from system to system, does not specify type of storage or type of data.

Structure charts

visualizes relationships between modules of a computer program, describes functions of sub-functions of a system.

Modular design

process of designing system modules individually, then combining the modules to form a solution to an overall problem.

top-down design

partition of a problem into smaller problems

pseudocode

used to describe algorithms, artificial language

module

complete/independent part of a program or an algorithm

modular programming

partitioning a computer program into separate sub programs (easily modified and maintained)

modular language

language that supports modular programming

Prototype

preliminary version of a final product

requirements of a prototype

• attracts attention of the client

• provides enough concept for investors

• encourages active participation between users and developers

• gives idea of final product

• helps identification of problems

• increases development speed

Iteration

repetition of a set of instructions a number of times until operations yield desired results

Consequence of no collaboration

the end-user is unsatisfied with the product

High accessibility

meets as many needs as possible

Usability

potential of a product

Egronomics

design of safe and comfortable products

Eight quality components of usability

1. Complexity / Simplicity - amount of effort for a result

2. Effectiveness - comparison of user performance against a defined level

3. Efficiency - task completion time after the initial adjustment period

4. Error - number, type, time needed to remove from errors

5. Learnability - time used to accomplish tasks on the first use

6. Memorability - how memorable the system is

7. Readability - speed and comprehension

8. Satisfaction - attitude of users towards the product

Visual impairment and color blindness solutions

braille devices, text to speech, adjust color values on screen

Hearing and speech impairment solutions

replace sound signals with visual effects or vibrations, subtitles

Cognitive problems and learning disability solutions

multi-sensory experience, basic word processor, active participation, positive reinforcement

Mobility impairment solutions

left-handed keyboards, replacement of some devices, tracker ball, special knobs, sip-and-puff (SNP), morse code, natural language processing, word prediction

Usability problems

• hard to use

• difficult to read

• unnecessary pages and redirections

• not visually appealing

• unable to quickly locate a product

• no FAQ or customer support