Units 3 & 4 Vocab. Flashcards
server
a computer that knows how to pass messages to other computers
packets
small pieces of info passed b/w computers
addresses
’s that uniquely identify a computer on the network
protocol
rules governing the transfer of info between computers
What are servers connected by?
telephone poles & wires on land and cables under sea
TCP/IP
Transmission Control Protocol. Internet Protocol. rules & instructions on how 2 send info over the internet.
IP address
each device has one. 4 numbers, each b/w 0-255 (cuz 4 bytes). 128.244.50.1
DNS
Domain Name System (or Service or Server), an Internet service that translates domain names into IP addresses
how many possible IP addresses? is that enough?
abt 4 billion. no.
IPv6
6 bytes. abt 281 trillion possibilities.
man-in-the-middle attack
network packets r easily intercepted and changed. rogue server could manipulate communications b/w 2 individuals or just gather info.
solution to maninmiddle attack
trust. only phone companies & qualified individuals are allowed to operate major internet servers. or cryptography to encode info.
Dictionary Attack/Brute-Force Attack
a computer can try thousands of word or letter combinations per second to guess ur password
bad & good passwords
bad = only words good = 12+ random letters & symbols
phishing
type of social engineering. when an email and/or website pretends to be someone else & tries to get u to type in ur password & send it to them.
social engineering
security attacks that prey on human psychology
malware
programs that do bad things to ur computer or device - erase files, steal information, take pictures with ur webcam, etc.
virus
most common type of malware. most comp’s come w/ anti-virus software now. free anti-v programs = AVG Free & Avast. cuz v is a program, user must download & run virus somehow. might be disguised as game/video. some take advantage of vulnerabilities in comp systems (Ex: memory stick that automatically runs when u plug it into a computer). must be created for specific operating systems.
other types of malware
trojans, worms, spyware, rootkits, crimeware, zombie computer, botnet, pharming, Van Eck phreaking
input device
anything that lets u interact w/ the PC Ex: keyboard, mouse, microphone
output device
anything that the PC uses to show u what u did Ex: monitor/display, printer, speakers
peripheral
anything connected to the computer, but not inside the case Ex: keyboard, monitor, printer
storage devices
anything that stores info for the computer.
a place to put all those 1s and 0s
capacity measured in megabytes
Ex: hard disk drive, optical disc drive, USB flash drive/memory stick
hard disk drive
stores info for a computer using a series of magnetic plates. a magnetic arm can read & write the info on the plates, while the plates spin. don’t put a magnet close to one. could die out of box/last a decade. predicting failure = difficult. modern capacity - 250GB - 2TB
optical disc drive
bounces a laser beam off the shiny surface of a disc to read it. the reflective surface actually has microscopic pits & grooves in it to store bits.
diff b/w CD’s, DVDs, and Blu-Ray
ability to fit more pits & grooves into less space using smaller wavelength lasers
rainbow - red light > green light > blue light; each wavelength = size of each hole
Random Access Memory (RAM)
fast, temporary storage that the PC uses for what it’s doing at that moment comes in “sticks” capacity of 1 stick - 1-4GB Ex: opening documents, running programs, mouse pointer location
expansion cards
add some kind of functionality to a PC getting getting rarer, since lots of functions (network, graphics, sound) r built in2 motherboards now (on-board)
network card
allows a PC to go on a network
graphics card
processes graphical info (usually 3D) for the PC
Power Supply Unit (PSU)
provides power to the internal components of the computer. diff things might require diff types of connection. PSUs also have wattages - some things might require more watts than others
Central Processing Unit (CPU)
the part that actually performs the instructions & calculations given by programs. connected to all the other parts of the computer via the bus on the motherboard.
motherboard (mobo)
connects everything together and lets the other parts communicate lots of diff places for plugging things in: slots, ports, sockets, connectors
form factors
diff sizes of motherboard
bus
physical connections (wires) and protocols that allow devices to communicate on motherboard
software
the instructions for the computer
tells the CPU what to calculate
tells the other hardware what to do
operating system (OS)
the most basic level of software
handles the low-level hardware instructions
- translating the signals from the mouse into actual cursor movements
- displaying pixels on screen
- reading & writing from a hard drive
provides an environment for other software to work
common OS’s = Microsoft Windows, Mac OSX, Linux
software for one OS won’t work on another
drivers
instructions for the OS to use other devices
special additions to an OS that lets it use new hardware (usually come w/ CD or something to install the driver)
ex: an OS might not know how to use a printer until it has the right driver for it
program
software that a user interacts with, that lets u do something
Ex: Microsoft Word, Mozilla Firefox
how OS’s, programs, and drivers all work together
BIOS
Basic Input/Output System
software built into the motherboard that runs when a PC is booting
most important thing it does = decide what storage device to use to finish booting (load an OS). will typically use hard drive, but can load an OS from ANY storage device
- a CD, DVD, or memory stick
can access by pressing Delete, F1, F2 or F10 while PC is loading (keep tapping)
bootstrapping/booting up
describes a comp when it is just turned on
command line/shell
early comp’s didn’t have graphics - if u wanted to do anything u would have to type commands for the comp to do
still used today.
someone proficient with the command line can navigate the comp & do some complex tasks more efficiently
prompt
a sequence of characters that the shell uses to inform u that it’s ready for a command
path
the folder/directory u r in
switch/option
Ex: /w
changes the behavior of the command
can have 1+ switch
read & write
the words used to refer to getting data from a storage device and putting data on a storage device
Van Eck phreaking
the process of eavesdropping on the contents of a CRT or LCD display by detecting its electromagnetic emissions.
