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