IB Computer Science Topic 1

SaaS (Software as a Service)

cloud based software delivery model where users subscribe to and access applications over a network

The four types of changing to a new system

parallel running, pilot running, direct changeover and phased conversion

Parallel Running

both the old and new system run at the same time

pros of parallel running

There is a back up system if the new one fails;

Output from both systems can be compared to see if the new one works

cons of parallel running

expensive to maintain both systems

Pilot Running

small group of the business tests the new software while one keeps using the old one

pros of pilot running

All features tested b4 adoption;

Staff who are part of pilot can train others;

If failure, only small part of the system;

cons of pilot running

No back up for pilot group in case of failure

Direct Changeover

immediate change to the new system

pros of direct changover

immediate change; new system available immediately

Phased Conversion

the new software introduced in phases, and old software is slowly phased out

pros of phased conversion

Allows ppl to get used to new system;

Training can be done in stages

cons of phased

If system fails, no backup for that part of the system

User Acceptance Testing

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

Debugging

finding and removing bugs from computer hardware and software

Beta testing

real world exposure for the product to get feedback from users

User documentation

Documentation to support users of computer systems including hardware and software

Methods of user documentation

help files, online documentation, printed manuals

Possible causes of data loss

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

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

Methods of preventing data loss

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

Strategies for managing/releasing updates

automatic updates, manual updates

Hardware

parts of the computer you can touch

Software

collection of programs and instruction that control the computer

Peripheral

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

Network

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

Human Resources

the humans operating the computer

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

DNS server

server translating domain names into IP addresses

Router

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

Firewall

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

Ergonomics

the study of people's efficiency in their working environment

Accessibility

how the system can be accessed for information exchange and operation

Ways to improve the accessability of a system

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

issues with changing softwares

users will not like the changes;

Some features omitted/not used;

The old system may be faster;

Incompatible with other software;

SAAS benefits

Saves money, less employment staff, pay as you go, easy maintenance, scalability

SAAS drawbacks

Availability, security, compliance, data corruption/recovery, provider gets acquired (smb buys it and changes it)

Failover system

is 1 syst fails, theres a back up system w the same data and capabilities that can take over

Redundancy

multiple servers or hard drives for storage that can take over/used when the primary one is down, identical data to the primary system

Removable Media

repetitively update a removable hard drive w data you want to preserve

Offsite/online storage

backs up all data into an online system, away from where computer is located (icloud)

Physical security

placing computer/storage devices in a place that is secure from environmental conditions or intruders

stakeholders

A person w an interest/concern in something, esp a business

(Owner, user, manager, shareholder, employee)

Patch

temporary fix between full releases

how to obtain patches

automatically updates;

manual update;