Computer Science IB HL: Topic 1 - System Fundamentals

Methods of providing user documentation

Manuals Embedded Assistance / Integrated user assistance FAQ Live chat sessions Online portals / web portals Remote desktop connections

Managing Change

Recognizing changes in the broader business environment and adjusting other impacted systems. Training employees on the appropriate changes. Winning the support of the employees with the benefits of the changes. Documenting the change process, in case problems arise after installation of the new system.

Methods to avoid data loss

Regular backup of files using hard disks Firewall installation Data storage in two or more locations Removed hard copies Installation of an Antivirus program Human reduction techniques / failsafe Online autosave backup

Social and ethical issues associated with a networked world

Reliability Integrity Inconsistency Security Privacy Anonymity Intellectual Property The Digital Divide and Equality of Access Surveillance Globalization and Cultural Diversity IT Policies Standards and Protocols People and machines Digital Citizenship

Benefits of SaaS

Scalability - As an organisation grows, more users need to be added to a system, rather than purchasing additional in-house server hardware and buying more software licences, an organisation can simply adjust their monthly SaaS service subscription. Accessibility - A browser and an internet connection is all that's usually required to access many SaaS applications. Upgrade-ability - A service provider deals with hardware and software updates. Resilience - Infrastructure and data reside in the cloud service provider's data-center. If some from of disaster should occur on an organisation's premises, the system can be used remotely with internet. Collaborative tools - Many SaaS solutions offer online tools for collaboration.

Methods of delivering user training

Self-instruction / self-study Formal classes Remote/Distance learning/online training

Hosting and Installation

Should the system be installed on-site within an organisation, or should it be hosted remotely in the cloud?

Localization

Strategies that adjust products to fit with target customers

Failover system

System which will take over the role of a primary system if it fails.

Software as a Service (SaaS)

"on-demand software" software distribution model in which applications are hosted by a vendor or service provider and provided to customers over a network.

Limitations of SaaS

*Data security* issues from trusting your information to someone else (loss of control) Host may be in different *time zone* so maintenance is inconvenient User *feedback* hard to get if host is not user (DS, TZ, UF) Dependence on third party Dependence on internet connection risk of data loss not as powerful

Four Strategies for Integration

1. keep both info systems, develop them to have same functionality (high maintenance cost) 2. replace both info systems with a new one (increased initial cost) 3. choose best info systems from each company and combine them (difficult for employees to work with info systems from another company) 4. choose on company's info systems and drop the other companies' (policy issues)

client-server

A network architecture in which a system is divided between server tasks performed on the instructions received from clients, requesting information.

Network as a Service (NaaS)

A service provider offering where clients can purchase data services (for example, e-mail, LDAP, and DNS services) traditionally hosted in a corporate data center.

Planning for change

Alignment: Aligning the organisational goals with the new system? Measurement: How will the success of the change be measured (what data should be collected before the changes)? Communication: How will the change be communicated to stakeholders? Compatibility: How compatible is the new system with existing dependent systems? What data conversion is required for the new system? Installation: Which installation process would work best for the organisation?

Alpha testing

An attempt by the firm to determine whether a product will perform according to its design and whether it satisfies the need for which it was intended; occurs in the firm's research and development (R&D) department.

Domain Name System Server

Attributes names to network addresses and therefore resolves names by assigning them to the appropriate network entity.

User documentation

Documentation to support users of computer systems including hardware and software

Data loss

Error conditions where data is lost or destroyed due to system failure, storage negligence, or even transmission/processing errors

Debugging

Finding and fixing problems in your algorithm or program.

firewall

Hardware and/or software that guards a private network by analyzing the information leaving and entering the network

System life cycle

The course of development changes through which a system passes from its conception to the termination of its use; for example, the phases and activities associated with the analysis, acquisition, design, development, testing, integration, operation, maintenance, and modification of a system.

Usability

The degree to which a system is easy to learn and efficient and satisfying to use Complexity Effectiveness Efficiency Error Learnability Memorability Readability Satisfaction

Help files

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

Shared Best Practices

Thorough and clear documentation will allow all users of a system to follow best practices for system use.

Client

a computer accessing resources hosted by another computer/the server

Server

a computer hosting resources to be shared across the network

Legacy Systems

a computer system of application program which continues to be used because of the cost of replacing or redesigning it and often despite its poor competitiveness

Network

a group of computers connected toether to share resources such as documents and printers

Dependency

a logical relationship that exists between the project tasks, or between a project task and a milestone

upgrades

always contain novel functionalities

Prototype

an original model on which later versions are patterned. Encourages active participation between users and developers Gives an idea of the final product Increases system development speed

Hardware

anything within a computer that you can physically touch

Strategies for managing/releasing updates

automatic updates, manual updates

Parallel Running

both the old and new system run at the same time

Consequences of data loss to individual users

can lose personal information (ex. address, social security number, health information or bank account information)

Consequences of data loss to companies

can lose reputation/customers, may be sued/have to pay fines

Software

collection of programs and instruction that control the computer

Methods of preventing data loss

create a backup, RAIDs (ex. data mirroring), antivirus softwares, physical security

Infrastructure as a Service (IaaS)

delivers hardware networking capabilities, including the use of servers, networking, and storage, over the cloud using a pay-per-use revenue model

Benefits of interviews

detailed information. two way and face to face

User acceptance testing

determines if the system satisfies the business requirements

dumb terminal

device that consists of a keyboard, a monitor, and a network card that is connected to a server or powerful computer. Dumb terminals depend entirely on the computer to which they are connected for data processing

Peripheral

devices attached to the computer that allow interation and the exchange of information (ex. keyboard, mouse, screen)

Software incompatibility

different software entities or systems cannot operate satisfactorily, cooperatively or independently, on the same computer, or on different computers linked by a local or wide area computer network

redundancy

duplication of storage devices and stored data of a computer system intended of securing the stored data

Integration testing

entire system is tested at the same time to verify that all components can work together

Releases

final, working versions of software apps. Finished beta and alpha testing

Benefits of direct observations

first hand, unbiased information

Drawbacks of surveys

hard to ask the right questions

Beta testing

having potential consumers examine a product prototype in a real-use setting to determine its functionality, performance, potential problems, and other issues specific to its use

Methods of user documentation

help files, online documentation, printed manuals

Operating system

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

Accessibility

how the system can be accessed for information exchange and operation

Debugging

identifying and removing errors from computer hardware and software

Updates

improves a product in a minor way by adding more funcitionalities

Stakeholders

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

Business mergers

joining of two businesses Systems used by the companies may be very different

Benefits of surveys

little time, simple, large amounts of data

Direct Changeover

moving straight from the old to new system

router

networking device that accepts incoming quanta of info, reads destination address and distributes them across networks

Pilot Running

one section of the business is trying out the new software while one keeps using the old one

The four types of changing to a new system

parallel running, pilot running, direct changeover and phased conversion

Drawbacks of direct observations

people change their answers

end-user

person who is going to use the product

Verification

process of ensuring that the data input is the same as the original source data.

Validation

process of evaluating whether data input follows appropriate specifications and is within reasonable limits

Change management

process of shifting individuals, teams, departments and organizations from a present state to a desired state

Firewall

protects the network traffic, decides what gets access and what doesn't

Beta testing

real world exposure for the product to get feedback from users

thin client

relatively low performance terminal, which heavily, but not entirely, depends on the server to which it is connected

Router

routes network packages betwee two networks, usually using a different medium like phone cables or glass fiber

DNS server

server mapping when addresses to IP addresses allowing us to surf the web without looking up IP addresses

Phased Conversion

slowly implementing the new software

Platform as a Service (PaaS)

supports the deployment of entire systems including hardware, networking, and applications using a pay-per-use revenue model

Unit testing

test individual units or pieces of code for a system

Human Resources

the humans operating the computer

User Acceptance Testing

the last phase of software testing in which actual software testers test the software in real world scenarios

Ergonomics

the study of people's efficiency in their working environment

Drawbacks of interviews

time consuming

Ways to improve the accessability of a system

touch screens, voice recognition, text to speech, braille keyboards, braille printers

patches

used by companies to update apps by fixing known bugs

Possible causes of data loss

user error, malicious actions of a third party, theft, viruses/malware, hardware malfunction, natural disaster

Dry-run testing

using pen and paper by the programmer. The programmer mentally runs the algorithm. Decides what the output should be