ib computer science (sl) | paper one

If a new system is to be started, the current system must be studied first. What are four ways this happens?

Interview, Questionnaire, Document Collection, Observation

(Studying Systems) Interview

Detailed with key people, time, consuming

(Studying Systems) Questionairre

Reach large audiences quickly, may not be well designed and could get bad user input

(Studying Systems) Document Collection

Good quality objective data, documentation may be limited

What is the IEEE Standards?

Institute of Electrical and Electronics Engineers Standards Association, an organization within IEEEE that develops global standards for a broad range of industries.

What does the requirement specifications document do?

A description of a software to be developed

What are four issues that will come up when a new system is put in place?

One The clients and managers may need retraining. Two A period of adjustment. Three Software may not be able to deal with the new system. Four Hardware may not be able to deal with the new system.

What is the purpose and goal of change management?

To move towards a future desired state.

Define a legacy system?

A system that continues to be used because of the cost of replacing or redesigning it but is large, monolithic, and difficult to modify.

What is IaaS?

(Infrastructure) IaaS is a cloud service that provides basic computing infrastructure: servers, storage, and networking resources. In other words, IaaS is a virtual data center.. (Can be compared to a leased car, want an upgrade, just lease a new one)

What is PaaS?

(Platform) PaaS refers to cloud platforms that provide runtime environments for developing, testing, and managing applications. (Can be compared to a taxi, you don't drive a taxi yourself, but simply tell the driver where you need to go and relax in the back seat.)

What is SaaS?

(Software) SaaS allows people to use cloud-based web applications, such as gmail. (Can be compared to a bus, since buses have assigned routes, and you share the ride with other passengers.)

What is NaaS?

Network as a service (NaaS) describes services for network transport connectivity. NaaS involves the optimization of resource allocations by considering network and computing resources as a unified whole.

What are advantages of cloud computing?

Convenient, security, backups, collaboration, environmentally friendly

What are disadvantages of cloud computing?

Security, service outage, storage limits, slower speeds, limited features

What are four ways to change from an old system to an new system?

Direct, Parallel

What is data migration? What are issues related to it?

Moving data to the new system, there may be poor data quality in the legacy system.

When testing software, what are four types of data that should be tested? Give examples of these.

Normal (This is data that would normally be entered into the system, such as a grade between 1 and 99), Extreme (Extreme value are still normal data. However, the values are chosen to be at the absolute limits of the normal range, such as a grade of 0 and 100), and Abnormal (Data that is not normal that should be rejected, such as a negative grade)

What are different methods of providing user documentation?

Manuals, FAQ, Online Portals, E-Mail Support, Live Chat Sessions, Remote-Desktop Connection, Embedded Assistance

What are the three methods of user training?

Self Instruction, Formal Classes, Remote/Online Training

List the seven ways that data loss happens and how each can be prevented?

Accidental Deletion (Recovery Software), Computer Virus (Antivirus Scans), Physical Damage (Care/Backups), Continued Use After Signs of Failure (SMART), Power Failure (Uninterrupted Power Supply), Natural Disasters (Surge/Backup), Firmware Corruption (Backup/Logic Boards)

What does HDD stand for?

Hard Drive Disk

What does SSD stand for?

Solid State Drive

What does SMART stand for?

Self-Monitoring, Analysis and Reporting, Technology

What is pre-alpha?

Not all features but demonstrates some

What is alpha?

Internal release for testing

What is beta?

First release for outside testing

What is Release-Candidate?

Features compare but bugs exist

What is General Availability?

Stable release

What is failover system?

Failover is a backup operational mode in which the functions of a system component (such as a processor, server, network, or database, for example) are assumed by secondary system components when the primary component becomes unavailable through either failure or scheduled down time. Used to make systems more fault-tolerant.

What is a Patch?

Free, a small bug or security fix.

What is an update?

Free additional content/newer version for a software.

What is an upgrade?

Paid additional content/newer version for a software.

What is a release?

Paid, the actual sale/release of the whole software.

What is the order of software release?

Patch > Update > Upgrade > Release

Explain the difference between a fat client and a thin client using the idea of a PC and a Chrome Book?

A fat client will perform the bulk of the processing required by the end user, such as a user using a program on their PC. Client hardware and software can be streamlined in a thin client setup where the bulk of the processing and software is managed directly by the server and the thin client is little more than a screen with a computer that has a graphics card and a network card, such as a chrome book.

What is the function of a server? Use League of Legends as an example.

What the end users connect to, and runs/hosts the software they are using. For League of Legends, while the users' PCs run the client-side version of the game, they are all connected to the server and the server is technically running the match by connecting each user to each other by sending data. However, servers can also be used to store data and share things online, and host things such as a websites.

What is an IP address?

a unique string of numbers separated by periods that identifies each computer using the Internet Protocol to communicate over a network.

What is the difference between IPV4 and IPV6?

IPv6 is an upgrade that has vastly larger address space (32 bit vs. 2^128 bit). Besides being larger and being able to host (theoretically) more than enough users, it also has multiple improvements from IPV4.

What is DNS?

The Domain Name System (DNS) converts domain names or host names into IP addresses. Instead of having to remember a host's IP address, DNS allows you to use a friendly name to access the host. The DNS does all of the work to find out where to go by first looking at the end of the url (.com), and then for the actual url, connecting you to that ip.

What does a router do?

A router is a device that transfers data packets between networks. Common application for this are the exchange of data between a home network and the internet (via the Internet Service Provider (ISP)).

What does a firewall do?

A firewall is a network security system that monitors incoming and outgoing packets based on a set of security rules. It acts as a protective barrier between a trusted or managed network and an external or unmanaged network. A firewall is generally software based but can be a configured hardware device.

What does the word iteration mean?

Iteration, in the context of computer programming, is a process wherein a set of instructions or structures are repeated in a sequence a specified number of times or until a condition is met. When the first set of instructions is executed again, it is called an iteration.

What is the 7+2 Principle?

Limiting the number of options in a navigation menu to seven, since by George A. Miller's studies, the human brain can only remember 5-9 things at a time.

What is the 2 Second Rule?

A loose principle that a user shouldn't need to wait more than 2 seconds for certain types of system response, such as application-switching and application launch time.

What is the 3 Click Rule?

According to this rule users stop using the site if they aren't able to find the information or access the site feature within 3 mouse clicks.

What is the 80/20 Rule?

The understanding that 80% of your business comes from 20% of your customers, coming from the Pareto Principle.

What is the Inverted Pyramid?

The inverted pyramid is a writing style where the summary of the article is presented in the beginning of the article. Makes use of the "waterfall" writing effect. The article begins with a conclusion, followed by key points and finally the minor details such as background information.

What must be true for technology to be usable?

a clear, self-explanatory navigation, precise text-presentation, search functionality and visible and thought-out site structure.

What are other design rules to follow?

One Don't use popups, Two Don't change the user's windows size, Three Don't use too small fonts, Four Don't have unclear link text, Five Don't have dead links, Six One animation per page (? why tho), Seven Make it easy to contact you, Eight Your links should open in the same window

Star Topology

Nodes/Computers are connected to a central node (computer or hub)

Ring

Nodes/Computers connected in a circle; no central node

Bus

Connects all devices through a common cable

Server

Computer system or software application that provides service to other computer systems on same network

Client

Requests service from above connected to same network

Hub

Connection point for devices on a single network that transfers data from one device to all connected devices, slowing down network

Switch

Hardware that knows which port to send data to

Router

More sophisticated than above two, can join multiple networks and acts as intermediary between networks for effective and efficient data exchange between devices

LAN

Connects computer systems within a small area such as house, office building, or school, allowing use of peripheral devices such as printers and external hard drives by connected computer systems

WLAN

Similar to LAN but wireless; easier for laptop and mobile devices but less secure

VLAN

Partitions LAN

WAN

Connects computer systems within large geographical area, such as cities, countries, or network of countries

SAN

Allows large storage devices to be accessed by servers conveniently

Intranet

Collection of private computer networks within a company, school, or organization, whose main purpose is to facilitate communication between individuals or work groups and to improve data sharing

Internet

Global network of a large array of computers and networks connected together

WWW

Consists of websites and webpages, and support for services such as email and file transfer

VPN

Makes "tunnelled" network connection through Internet or any public network. Enables device to exchange and access data across Internet as if it were directly connected to a private network

PAN

Interconnects devices centered around one person's workspace, maximum 10m range (an example is bluetooth)

P2P

Uses distributed network architecture where all computer systems (nodes or peer) in network are decentralized and are clients and servers at the same time

Standards/Protocol

Provide common international "language" and rules that enables compatibility for all computer systems globally

TCP/IP (and OSI)

Most widely used examples of above. Reference model that aims to facilitate communication across variety of systems.

Data Packet

Portion of messages that is transmitted through network. Has data such as check digits and destination address.

Error Checking

Process to determine error

Error Correction

Ability to repair error

Bandwidth

Theoretical speed of data in media

Through Put

Actual transfer rate of data. Affected by interference, traffic, number of connected devices, errors, etc

Bottleneck

Created by slowest segment of network that affects above

Good Put

Transfer rate of usable data

Checksum

Extra digit added to numerical data (to make sure it is good when transmitted)

Data Compression

Reduction of bits by encoding data using fewer bits than original file/representation

Lossy Compression

Some loss of information, no way to get original file back. (examples are JPG, MPEG2, etc)

Lossless Compression

Reduces number of bits by identifying and then eliminating statistical redundancy. No loss of information.

Fibre Optic Cable

Carries beam of light, used for data transmission and telephone lines. Higher speeds with high security but very expensive.

Coaxial Cable

Cheap to install, consists of two copper conductors. Used in networks as well as carrying TV signals.

Bluetooth

Uses microwave radio to exchange data at very low power levels. Frequencies change regularly.

Modem

Allows connection to internet

(WAP?)

Provided by wireless router, allows wireless data transfer between device and network

Network Card

Required for devices to connect to wireless network

DHCP

Protocol that allows server to automatically assign IP address to client device. Very effective and convenient.

Firewall

Network security system that determines what data comes in/goes out of network or computer

SSID (Service Set Identifier)

"Name" of WLAN. Maximum 32 characters, case-sensitive.

Network Drivers

Operates or controls hardware of network card, acting as a translator to device.

Mac Address

Based on this, network permit access to certain devices. Consists of 12 digits or letters e.g. 1a:2b:3c:4d:5e:6f; what every network card has when manufactured.

IPV4

12 Digit adress

IPV6

30 Digit/Letter Address

NAT

Network Address Translation

Extranet

External extension of Intranet by reaching into the internet. Includes all files, programs, etc a computer needs

OSI

Seven layer system where each layer deals with a layer of communication

Bit (b)

Binary Digit

Byte (B)

8 Binary Digits