Comp Sci Unit 1 (1.2.1 - 1.2.16)

Terminology

Hardware, software, peripherals, network, human resources

Hardware

Any physical parts to a computer
EG:
CPU
Keyboard
Mouse

Software

Programs/instructions that control the computer
Non-physical
EG:
Databases
Web Browsers
Communication platforms

Peripherals

An outside device that allow the computer to interact with the environment or exchange info
Connected EXTERNALLY
Used to expand the host’s capabilities
EG: Input Peripherals
Scanner
Microphone
EG: Output Peripherals
Screen
Speakers

Network

Group of computers connected together to share resources
Can interconnect with other networks to form larger networks

Human resources

The people operating the computers
EG:
The people who are responsible at maintaining employee data, promotions or hiring

Roles of a Computer

Client, Server, DNS Server, Firewall, Router

Client

Computer accessing resources that are hosted from another computer
Resources may include:
Documents
Printers
Scanners

Types of Clients

Fat, thin, hybrid

Fat clients

Performs the bulk of the processing
Doesn’t necessarily rely on the server

Thin clients

Relies on the resources from the server

Hybrid clients

A mix of both fat and thin clients

Server

A computer hosting resources to be shared in the network for clients to access
Combination of both hardware and software
The computer provides services for other users to access
EG:
Google
Wikipedia

DNS Server

Special type of server
Maps web addresses to IP addresses
IP Address: Internet Protocol, identifies a device/network on the internet
Allows for the user to access any website without having to look for the IP address

Firewall

Computer/software package
Any message passed through the internet passes through a firewall
Monitors/protects network traffic of a computer
Decides which computers get access to the network based on a set of rules
Basically like a security service

Router

A routing network that passes information between two or more networks
Uses a different medium for information transfer
Also forwards data to the intended IP address
EG:
Phone Cables

Relevant Stakeholders in developing a new system

Systems analyst, end users, software manufacturer, client company

Systems analyst

Collects information on present systems in order to examine the problems of it
Uses that information to develop a more efficient system
Designs the new system
Tests the system for any arising issues
Evaluates the system to see if it matches expectations

End users

The clients of the service
The actual users of the system

Software manufacturer

Builds/develops the systems in order to be sold

Client Company

Employer organization

Methods for researching

Questionnaires, observations, interviews, documentation

Pros of Questionnaires

Answered quickly/honestly
Cheap
Analysed automatically

Cons of Questionnaires

People don’t often complete/return it
Unclear questions cannot be explained
Difficult to ask specific questions

Pros of Observation

Systems analyst can easily see advantages/disadvantages of current system
Not expensive

Cons of observation

Person being watched may feel uncomfortable and work differently than usual

Pros of interviews

Questions can be explained
Questions can be changed
A full set of data can be recorded

Cons of interviews

Takes more time/money
Answers aren’t always honest

Pros of Documentation

Saves time
Can see existing inputs/outputs
Allows for prediction of the size for the new system

Cons of Documentation

Very time consuming/expensive
Time could be wasted if info isn’t relevant to existing system

Appropriate techniques for gathering information to arrive at a workable solution

Search, review current systems, analyze products, consult other people

Search

Identify, collect, and organize various sources to find information
E.g. search engines, databases, libraries, news articles

Review current systems

Analyze current systems for effective features, functions, and other elements
E.g. system documentation

Analyze Products

Analyze system/products that have been developed for the same purpose and end-users
E.g. look for vulnerabilities, limitations, successful characteristics, breakthroughs, benefits, and design features

Consult other people

Identify all critical organizational capabilities that are essential to support effective planning and development
E.g. interviews

Representations to illustrate system requirements

System flow chart, data flow diagram, and structure chart

System flow chart

Diagrams representing how different parts of the system are linked together and how the system should work in general

Data flow diagram

Diagrams representing how information is moving through the system together with identifying all relevant inputs and outputs to the system

Structure charts

Diagram representing the organization of a system, usually with showing the different parts in hierarchical order

Prototype

the process of building a model of a system, used to help system designers build an information system that is intuitive and easy to manipulate for end-users. A process that is involved with analysis phase of the systems development life cycle

Purpose of Prototypes

Reduced development time, reduces development costs, requires user involvement, developers receive user feedback, facilitates system implementation since users understand what to expect, results in higher user satisfaction

Steps of software life cycle

Inquiry and analysis
Developing ideas
Creating the solution
Evaluation

Iterations

the repetition of a set of instructions for a specific number of times or until the operations yield a desired results

Importance of iterations

plenty of opportunity for user feedback, more likely to detect issues, improved usability, efficient and cost effective adaptability to project/client/team

Consequences of failing to involve the end-user in the design process

solve a different issue(s), address issues outside of the project’s scope, not addressing criteria issued by stakeholders, waste resources (time and money), be incompatible with end-user systems (app made for windows, but the computers are mac), end user may not be able to interpret UI elements

Social and ethical issues associated with the introduction of new IT systems

Firing workers because computer systems can do the same job but cheaper
Because of mobile phones, workers can be reached even out of work
Less social interaction due to home offices

Terms for usability

Learnability
Efficiency
Memorability
Errors
Satisfaction
Complexity/Simplicity
Effectiveness
readability/comprehensibility

Usability problems (examples)

GPS systems, tablets

Problems of usability in GPS systems

Low quality speakers
Outdated street data
Inefficient routing software
Poor antenna

Problems of usability in tablets

Accidental touches
Poor scaling
Small button size
Difficult to learn features of different brands

Methods to improve the accessibility of systems

Visual impairment (Braille input devices), speakers (text to speech),
Hearing and speech impairment (Subtitles), Cognitive problems & learning disabilities (Special software to provide sensory stimulation they need), Mobility impairment (Specialty keyboards/mice), Special replacements for common input items

Problems that come with Learnability

Very complicated and poor instructions

Problems that come with Efficiency

Very inefficient in processes and input

Problems that come with Memorability

Hard to remember

Problems that come with Errors

Having many errors that interfere with what the system is meant to do

Problems that come with satisfaction

Poor quality

Problems that come with Complexity/simplicity

So simple its useless, so complex it is hard to use

Problems that come with effectiveness

Doesn’t do its job

Problems that come with readability/comprehensibility

Not understandable

Moral/Ethical implications of interaction with humans and machines

AI and rights

Social implications of interaction with humans and machines

AI tricking humans with false info

Economic implications of interaction with humans and machines

Losing jobs for more efficiency

Environmental implications of interaction with humans and machines

Damaging environment, ways to make up with machines