IB CS Yr 1: Topic 1 - System Fundamentals 1.1

1.1.1-1.1.14

system life cycle

analysis → design → implementation → operation → maintenance

software life cycle

planning and analysis → design overview → development → evaluation

feasibility study

Technical, Economic, Legal, Operational, Schedule

legacy system

old technology, hardware, computer system, or application

business merger

combining of two or more business entities

reduced cost

main reason for business merger

SaaS

Software as a Service, data managed at a remote data center, subscriptions

changeover

process of putting a new system online and removing the old one

parallel changeover

both systems work in parallel for a short period of time

big bang/direct changeover

old system unplugged at the same time as new system is plugged in

pilot changeover

used in large organizations with multiple sites, there is one initial pilot group. new system extends over time

phased changeover

converts one module at a time, new system adoption takes longer

data migration

transfer of data between different formats, storage types and computer systems

functional testing

test functionality of individual components

data testing

when abnormal/normal/extreme data is put into the system

Alpha testing

done before public release in software lab

Beta testing

comments and suggestions from users

Dry-run testing

paper and pen test by programmer, mentally determines output

unit testing

individual parts are tested seperately

integration testing

entire system tested at once

user acceptance testing

if system satisfies customer needs before transfer of ownership

debugging

finding and correcting bugs in a program

validation

evaluating if data follows appropriate specifications within reasonable limits

verification

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

Internal documentation

code comprehension within source code such as meaningful variable names and comments

External documentation

separate from program, user’s guide. details of design and implementations

Manuals

can be on or offline. offline advantages- used without PC or internet. Is like a user’s guide

Email support

users contact support team with questions

Embedded Assistance

integrated user assistance- context specific, task specific, appears within program or system

FAQ

frequently asked questions for a common set of user problems. common on online forums

Live chat

good for emergency situations, feeling of being helped by a real person in real-time

Online portals

updated manuals support pages, and FAQs all at once

Remote desktop connections

specialized person connects to user’s computer via internet. Ideal for inexperienced users, poses a security risk

self-instruction

self-paced, self-motivated learning. lacks guided instruction, but no tuition fee

formal classes

open discussion between teacher and student, creates more ideas in person

remote learning

any location with a PC and internet connection. self promoted critical thinking. bad for dependent learners

data loss

error condition where data is lost/destroyed due to system failure, negligence, or transmission/processing error

causes of data loss

* accidental deletion
* administrative error
* misplacement
* building fire
* close without saving
* computer virus
* use after failure signs
* data corruption
* natural disaster
* outsider tampering
* physical damage of storage device
* power failure

data loss prevention

• regular backups

• use hard disks or magnetic tapes

• firewall installation

• data storage in multiple locations

• removed hard copies

• installation of antivirus program

• human error deduction techniques

  • online autosave backup

redundancy

duplication of storage devices and stored data, considered failsafe

removable media

permanent, external, non-volatile data storage (CD, diskettes, USB, DVD)

failover system

computer system ready to take over should the primary system fail

switchover system

primary and secondary server interchange primary role

patches

fixing known bugs/vulnrabilities

upgrades

novel characteristics and functionalities added, usually paid for

updates

improve product in minor way, add new functionalities

Release

final, working versions of software applications, been through tests