ISTM 210 Midterm (CH4-CH10)

systems development life cycle (SDLC)

process of developing software/information systems from beginning to end

SDLC phases

planning, analysis, design, development, testing, implementation and maintenance

planning

establishes the project’s direction, scope, feasibility and approval to proceed

technical feasibility

analysis assessing if the system is realistic and if the team has the necessary expertise to develop it

economic feasibility

analysis assessing if benefits exceed costs

legal feasibility

analysis assessing if the system meets regulations and laws

operational feasibility

analysis assessing if the organization will be able to operate and support the system effectively

scheduling feasibility

analysis assessing if the project timeline is realistic given available resources

requirements matrix

list of approved features and key characteristics of the new system that are required for success

analysis

teams gather and document the detailed business and system requirements

design

focuses on translating requirements into a blueprint for how the system will look like

development

coding phase where the system’s functionality is built

testing

ensures the system works as intended and meets all requirements before alunch

penetration testing

“white hat” hacking to identify security vulnerabilities

unit testing

testing of individual code components

integration testing

testing whether individual components work together properly

system testing

testing the entire integrated system against requirements

user-acceptance testing

testing whether end users will use the system effectively in real contexts

implementation

system is deployed for real use and users are trained

direct conversion

old system stops ad new system starts at one planned moment

parallel conversion

old and new systems run together until the organization trusts the new one

phased conversion

new system is introduced one feature, location or business unit at a time

pilot conversion

one site/group uses the new system first so the organization can learn before a wider roll out

maintenance

sustaining and improving the system overtime

as-is process

shows how a process actually works today

to-be process

how a process should work after a planned change

what is the gap between the as-is and the to-be process?

it is the project itself — every difference between the two becomes a requirement

readback

the discipline that catches both gaps

waterfall

development approach that emphasizes sequential phases, detailed upfront planning and formal approval of charges

agile

development approach that runs all phases quickly over a small slice of the system, then does it again over the next slice

scrum

the most common agile framework — work is organized into sprint cycles where each sprint ends with something that runs

sprint

short, fixed length iteration that ends with a working increment of the system

product owner

owns the backlog and decides what matters most

scrum master

keeps the process running and clears obstacles

SWOT Analysis

structured snapshot of a situation across 4 cells — strengths and weaknesses (internal) opportunities and threats (external)

ex of strengths

loyal customers, strong brand, skilled staff

ex of weaknesses

aging website, manual order entry, no mobile app

ex of opportunities

growing onlines demand, competitor outage, new supplier

ex of threats

larger rivals, larger ad costs, data-breach risk

needs

what a project’s goal is

requirements

a need that has been made testable

functional requirement

what a system does/must do

non-functional requirement

how well a system must perform

user story

requirement written from a user’s pov paired with acceptance criteria that makes it testable

acceptance criteria

specific, checkable criteria that must be true for a user story to count as done

say-do gap

difference between how people describe their wrok and how they perform it

MoSCow

sorts requirements into:

• must have

• should have

• could have

• won’t have this time

forces explicit decisions about what ships first

traceability

every requirement links backward to a source and forward to a test that will veryify it

make

organization writes code in house

offers greatest control and protection of intellectual property

build

organization hires and external consulting company or development firm to build the system

allows access to specialized skills so faster development timelines but can increase dependence on vendors and raise concerns on long-term control/critical knowledge

buy

organization purchases a commercial off-the-shelf solution that meets all or some of its requirements. typically the fastest and least expensive upfront but limits customization and locks the organization into vendor support and upgrade cycles

3 primary factors for make/buy/build

1. availability of commercial packages

2. availability of competent personnel

3. risk of losing sensitive information

packet

small chunk of data carrying addressing information so it can be routed across a network

internet protocol (IP)

handles addressing and routing

transmission control protocols (TCP)

adds sequence numbers, detects losses, retransmits missing data and presents they bytes to the application in order

user datagram protocol (UDP)

fires packets off without tracking losses or reordering them, trading reliability for speed

local area network (LAN)

set of two or more computers connected in close proximity

internet

global system of interconnected computer networks

hypertext transfer protocol (HTTP)

a protocol for transferring web-based information — web content is delivered using this

world wide web (WWW)

collection of interconnected documents and resources linked by URLs

transmission control protocol/internet protocol (TCP/IP)

internet protocol suite — IP addresses and routes packets, TCP can add reliable + ordered delivery for applications that need it

ping

a utility names after a sonar echo that tests basic network reachability and reports response time

domain name system (DNS)

translates human-readable domain names into IP addresses

virtual private networks (VPNs)

encrypted connections rhat allow secure access to private networks over the internet

coaxial cable

copper cable with a central conductor and shielding — commonly for cable internet and television

twisted pair cable

pairs of copper wires twisted together to reduce interference — commonly used for ethernet

fiber-optic cable

cable that carries data as pulses of light through thin glass or plastic fibers

what the web experiences as a single request and response

the network experiences as a managed swatm

bandwidth

how much a data connection can move per second — the width of the pipe

latency

how much one round trip between sender and reciever takes — the length of the pipe

IP address

the numeric address that identifies a network interface

internet service provider (ISP)

company that connects a home or business to the wider internet and routes its traffic toward everything else

3 literacy habits

1. treat padlock as the floor, not the proof of virtue

2. on networks you don’t trust, assume the local segment is hostile

3. notice what encryption does not hide

uniform resource locator (URL)

full address of a web resource, composed of a scheme, domain, optional path, optional query string and option fragments

query string

portion of a URL after a question mark, carrying key-value pairs that pass parameters to the server

scheme

https://

subdomain

www.store

domain

example.com

path

/products/shoes — what resource am i asking for

query string

?color=red&utm_source=newletter

what parameters ride along and who’s watching them

fragment

#reviews
where on the page should the browser jump

registerable domain

organization-controlled name immediately before a public suffix (.com or .co.u)

client

requesting side

server

side that answers

frontend

what runs on the client

backend

what runs on the server

static

same for every visitor, prepared in advance — shared content

dynamic

assembled per request — personal content

2xx code

success

3xx code

redirect

4xx

client side problem

5xx

server side problem

cookie

small piece of labeled text a server asks the browser to store and send back with every later request to that site

session

server-side memory about one signed in visitor, looked up on each request using an identifier carried in a cookie

caching

keeping a ready-made copy of content close to whoever will request it next, so repeat requests skip work and distance

browser cache layer

on the visitors own device

CDN edge cache layer

a provider’s servers in dozens of cities worldwirse

server-side cache

next to the application, in front of the database

content delivery network (CDN)

network of edge servers that stores copies of static content and serves each visitor from a nearby location

HTTPS

protects the conversation in transity