IB Comp Sci Review

bc i dont pay attention in class

DNS

DNS

Domian Name Server

stakeholder

the people or groups affected by or have an interest in a software development project / company.

examples of internal stakeholders

employees; managers; ceo; board of directors

examples of external stakeholders

clients; customers; investors; suppliers

accessibility

refers to the design of products, devices, services, or environments for people with disabilities or specific needs.

usability

the ease of use and learnability of a human-made object.

utility

the measure of whether the product/system does what the users want/need it to do.

ergonomics

the study of users in their work-environment to eliminate discomfort or injuries.

3 ways to provide user documentation

1. online support

2. printed manuals

3. help files

4 techniques to collect data

1. direct observation

2. surveys

3. interview

4. documentation

Prototype process

Design Prototype Build Prototype Test Prototype Give Feedback Refine Prototype Final Product

The steps that might need to be iterated are 3, 4, and 5.

cache memory

used to allow the CPU to access data quickly from the main memory (RAM)

the instruction cycle

Fetch- Instructions are fetched from the memory (RAM). Decode- The CU decodes the instructions that were fetched from the RAM and sends it to the ALU Execute- The ALU executes the instructions Store- The executed data is now stored in the memory.

static testing

Reviews walkthroughs or inspection of code. Like proofreading an essay. Involves verification; does not run program.

dynamic testing

Actually executing programmed code with a given set of test cases. Takes place when the program is run; may begin before the program 100% complete in order to test parts/ sections of code. Involves validation

alpha testing

Done within the organization as it is performed by testers who are usually internal employees of the organization Performed at the developers site

beta testing

Second phase of software testing Done before the release of a full product Small sample of users are testing this product before the product officially releases

white box testing

aka structural testing looks inside the software that is being tested and uses that knowledge as part of the testing process

black box testing

aka functional testing treats software under test as a lack box w/o knowing the internals. tests are using software interfaces and trying to ensure that they work as expected

automated testing

the use of a software (separate from the software that is actually being tested) to control and perform the execution instructions on a software.

This software testing method uses scripted sequences that are executed by testing tools.

user accepted testing

testing any new/updated system with end users to see if the product meets their expectations happy users = more productive users = good for developers

Human resources

both the people who work for a company or organization and the department responsible for managing resources related to employees often reffered to as the end users of a system

Network

can be as small as two computers or as large as billions of devices connected to one another

LAN

WAN

Two main types of Network Architecture

1. Client-Server Network

2. Peer to Peer Network

Client

a user’s computer (PC, MAC, Workstation) implies the computer is connected to a network where the computer may request data from the server.

Server

is a computer that provides services to the client computer. A server might be a web server of Google, print server, database server, file server or fax server.

modem

a box that connects your home network to your internet service provider (ISP) uses wide area network (WAN); essentially the modem connects to a greater network system is not responsible for your Wi-Fi

router

a box that allows wireless devices to be connected to the internet establishes a local network; uses local area network (LAN); you can print without internet because printers uses LAN creates and manages Wi-Fi requires a modem to connect to the internet

Advantages of Client Server:

1. A client server can be scaled up to many services that can also be used by multiple users.

2. Better security than a peer-to-peer network, you can have passwords to own individual profiles so that nobody can access anything when they want.

3. All the data is stored and backed up onto the servers which generally have far greater security controls than most clients.

Disadvantages of Client Server:

• More expensive to setup.

• Requires an experienced technician/engineer to maintain

• When the server goes down or crashes all the computers connected to it become unavailable to use.

• A client server can be scaled up to many services that can also be used by multiple users.

• Better security than a peer-to-peer network, you can have passwords to own individual profiles so that nobody can access anything when they want.

• All the data is stored and backed up onto the servers which generallyhave far greater security controls than most clients.

Domain

group of computers/ websites computers/websites that can be accessed and administered with a common set of rules.

IP Address

a unique address that identifies a device on the internet or a local network.

main purpose of DNS server

to translate a domain name into the appropriate IP address. This is done by looking up the DNS records of the requested domain. allows you to access an Internet location by its domain name.

Firewall

a network security device that monitors traffic to or from your network. It allows or blocks traffic based on a defined set of security rules.

How the internet reaches your computer from the ISP

ISP, Modem, Router, Computer

utilitarianism

When designing a new system, we want to design it for the greatest good for the greatest number of people.