⌨️Computer Science 1 Flashcards
Paper 1 and 2
comp 1.5: what are the 3 types of system software
utility/application software, device drivers, operating software
comp 1.5: what does the operating system do
a piece of software that controls system hardware, it has mangers for each piece of hardware
comp 1.5: name all of the managers used by the operating system
memory manager, user manager, process manager, file manager
comp 1.5: what is a CLI
it is a command line interface
comp 1.5: what is a GUI
it is a graphical user interface
comp 1.5 what is a WIMP
stands for Windows Icons Mice and pull down menus, it is a system of software features designed to simplify system operation for the user
comp 1.5: name 4 types of utility software
defragmentation, encryption, compression, backup
comp 1.5: what is a single user OS
it is an operating system interned to only have a single user at a time, although more than one user can use the OS at different times, the user manager keeps track of this
comp 1.4: what is social engineering
someone being influenced into giving away info that could grant access to accounts
comp 1.4: what is an insider attack
it is an attack by someone on the inside where the give away vunerable info
comp 1.4: what is an active attack
using a technical method, such as malware or other to compromise a networks security
comp 1.4: what is a passive attack
this is an attack where attackers eavesdrop by ‘sniffing’ data packets
comp 1.4: what is a penetration test
this is where an organization performs a controlled attack on itself to identify its weak spots, this can be performed by ‘ethical hackers’
comp 1.4: name all of the types (7) of malware
- viruses - program in a program that spread
- worms - code that spreads across a network without a host
- trojan hoarse - pretends to be a program its not
- ransomware - encrypts data on system, only decrypts when money is sent
- spyware - tracks activity and gathers info
- rootkit - modifies OS so antivirus does not work
- backdoor - opens access to a computer that another malware takes advantage of
comp 1.4: what are firewalls and what do they do
they are either hardware or software that ‘sits’ between the user and the internet that filter packets
comp 1.4: what are the 4 types of active attacks
- brute force - tries many combos of numbers and letters to find a password, this is slow
- dictionary - tries many common passwords
- DoS - denial of service attack, floods a server with many useless requests, can be blocked by a firewall blocking a certain ip,
- DDoS - distributed denial of service attack, used to unban an ip, requests are sent from a botnet
comp 1.4: what methods do firewalls use to filter packets
- ip filtering - the set of properties that identify a packet, together with the action to be performed on it, is known as an IP filter rule
- packet filtering - inspects data packets to see whether they meet a certain criteria
- port blocking - blocks certain ports that can be used by hackers to gain access, such as port 22
comp: what is a protocol
a set of rules
comp 1.4 what are the 4 methods of data interception
- MITM - a man in the middle attack intercepts data by intercepting the users connection to the internet and viewing network traffic
- insider attack
- packet sniffing - a hacker intercepting data transfered across a network
- SQL - structured query language, this is an attack where lines of code are inserted into a field in the website/other
comp 1.4: what are botnets
they are many machines infected with malware that can be used for DDoS attacks
comp 1.3: what is a switch in networks
it is a device that connects serval devices to make a wired network
comp 1.3: what is a network layer
they break up the sending of packets into different components, each component handles a different part of the communication(TCP/IP model)
comp 1.3: what is a NIC
a network interface controller is a device that provides connection between a device and the network
comp 1.3: what is a router
this is a piece of hardware that connects networks together
comp 1.3: what is a wireless access point
a piece of hardware which connects to a switch and allows WiFi devices to connect to the network
comp 1.3: what is a twisted pair cable
ethernet cable, made of eight wires twister into pairs to reduce interference
comp 1.3: what is a LAN
local area network
comp 1.3: what is a client server model
the server is in control of the network, the client askes and it gives a response
comp 1.3: what is a WAN
wide area network
comp 1.3: what is a pier to pier (P2P) server model
In a peer-to-peer (P2P) network, all computers have equal status - no computer has control over the network. There are no servers or clients. Instead, each computer is known as a peer close peer. On a network, a computer that has equal rights and control
comp 1.3: what is the process of a client server model
first the client asks the server then the porosesses the request and then responds.
comp 1.3: what are the advantages of the pier to pier server model
cheaper, more robust, and it commonly used for streaming
comp 1.3: how does the internet work
the router provides the internet connection, it connects to a ISP (internet service provider) which then connects to a DNS (domain name service) which is the backbone of the internet
comp 1.3: what is the star network topology
all clients are connected to the central switch or server. if one client falls off all of them don’t, often used for LAN
comp 1.3: what is the mesh network topology
no central server which can fail, all of the computers are connected to all of the rest, can be very expensive if its wired, no one point of failure
comp 1.3: what is a partial mesh network topology
the same as a mesh network topology but not all of the computers are connected to all of the others
comp 1.3: what is WIFI
it is a set of protocolos that enables devices to communicate across radiowaves, there are different standards of wifi that opperate ove different frequencies and speeds, its official name is IEEE 802.11x
comp 1.3: what is WEP
wired equivalent protection is the weakest protection and is protected by one password
comp 1.3: what is WPA protection
WIFI protected access is better than WEP, it uses one password and encryption
comp 1.3: what is WPA2 protection
WIFI protected access v2 is better WPA bc it uses better encryption
comp 1.3: what is the IP
internet protocol, defines how packages should be transmitted over a wireless network, an IP header is attatched to the data to store the sourse and destination
comp 1.3: what is the ethernet protocol
this is a protocol that defines how data should be transmitted over a cable
comp 1.3: what is the TCP
transport control protocol, this splits data into small packets each with a header that defines the destination and how it reaches there
comp 1.3: what is the cloud
these are large datacentres
comp 1.3: what is a mac address
every network interface controller is has a media access control address that is globally unique and allows data to be sent to individual users
comp 1.3: what is a public ip address
routers that connect to WAN have a public ip so devices on the WAN can send data to devices on the LAN
comp 1.3: what is HTTP
hypertext transfer protocol is a protocol that determines how data is transferred between browser and web server
comp 1.3: what is a private ip address
a private ip adress is the IP for devices on a LAN to use on that LAN
comp 1.3: what is FTP
file transfer protocol determines how binary data and text data are requested and sent to the client from the server
comp 1.3: what is HTTPS
HTTPS is secure HTTP that uses SSL (secure socket layer) in order to encrypt the data
comp 1.3: what is SMTP
simple mail transfer protocol determine how email data is sent from clients to servers
comp 1.3: what is POP
post office protocol is a protocol that determines how emails are retrieved from servers:
emails not in sync with the server
inbox is not kept consistern between devices
comp 1.3: what is IMAP
internet message access protocol is a protocol that determines how emails are retrieved from servers, it allows emails to be kept in sync, the inbox is consistent between devices
Comp 1.1: what is the PC and what does it do
The program counter is the part of the CPU that holds the address of the next instruction
Comp 1.1: what is the MAR
The memory address register is the part of the CPU that stores the memory address of where details to be stored of fetched
Comp 1.1: what is the MDR
The memory data register is the part of the CPU that holds data fetched from or to be stored to main memory
Comp 1.1: what is the ACC
The accumulator hoods the results of calculations
Comp 1.1: what is the ALU
The algorithmic logic unit performs calculations
Comp 1.1: what is the control unit
The control unit decodes instructions and signals to control how data moves around the CPU
Comp 1.1: what does the cache do
Stores commonly used instructions so they are faster to execute
Comp 1.1: what do registers do
Registers store small amounts of data needed for processing, they are very fast
Comp 1.1: what are the 4 types of register in the CPU
MAR, MDR, PC, ACC
Comp 1.1: what is primary memory
RAM
Comp 1.1: what is BIOS and what does it stand for
Basic Input/Output System
Comp 1.2: what does the rom do
Read only memory, this helps to wake up the computer and performs the post cycle
Comp 1.2: what is virtual memory
When to computer runs out of primary storage it can make up for this with secondary storage
Comp 1.2: what are the 3 types of secondary storage
Magnetic, optical, solid state
comp 1.2: what is the difference between a full and a full incremental backup
- a full backup is one that records the whole dataset
- a full incremental takes an existing backup and replaces it with updated info
comp: what is the DNS lookup
the DNS lookup is the prosess that matches ip to url so data can be transmitted between the client and website
comp: what is a url
this is a uniform recourse locator and it is contains info about the location of the webpage
comp: what is a intranet
a local restricted communication network
comp: what is lossless compression and what can it be used for
it is a form of compression that does not diminish the quality of the media, add what it can be used for
comp 1.2: what is lossy compression and what can it be used for
it is a form of compression that used and algorithm in order to compress videos and photos (not text) by removing data deemed less important
comp 1.2: what is compression
it is a method that is used to reduse file size
comp 1.2: what is bit depth in sound storage
it determines the number of amplitudes values can be stored per sample
comp 1.2: what is sampling in audio storage
where the mic measures the audio a certain amount of times a second
comp 1.1: what are the 4 registers in the cpu
MDR, MAR, ACC, PC
comp 1.1: what 2 parts of the FDE cycle does the control unit perform
fetches the instruction
decodes the instruction
comp 1.1: what 2 parts of the FDE cycle does the ALU perform
it gets the data for the instruction and executes it
comp 1.1: what is the address buss
carries memory addresses from the processor to other components such as primary storage and input/output devices
comp 1.1: what are the steps of the FDE cycle
Fetch decode execute
comp 1.1: what does the control bus do
it carries control instructions
comp 1.1: what does the data bus do
it carries data
comp 1.5: what is a process manager and what does it do
the process manager is the manager that controls the allocation of CPU resources
comp: what is a modem
the modem takes signals from the ISP and changes them into signals that your devices can interpret
comp: how do you prevent data interception
you use encryption to make the data safe
comp: what is a macro
it is a piece of software that is given permission to run by the user
comp: what is 2fa
two factor authentication, it requires to forms of authentication to provide access
comp: what is the tcp/ip model
it defines how devices should transfer data between each other, divides data into packets and the combines it at the end to form the whole dataset
comp: what do registers do
store small amounts of data used when processing
comp: what does cache do
stores commonly used instructions
comp: what is pseudocode
it is fake code that makes development easier
comp: how much can a floppy disk store
100KB - 1.44MB
comp: how much can a CD store
700MB
comp: how much can a DVD store
standard layer (one layer) can hold 4.7GB and a double layer disk can store 8.5GB of data
comp: how much can a blu ray disk store
single layer blu ray can hold 25GB and double layer can hold 50GB
comp: how much can a caset tape store
lots (don’t use on exam)
comp: how is a URL converted into a IP
the URL is sent to a DNS, DNS looks up the IP of the URL and sends it to the user, if it is not found the DNS sends it to a higher level DNS
comp 1.6: what is the data protection act of 1998
- it determines what companies can do with information they collect and the rights of the user to that data
- it has 8 rules
1. data must be used and processed in a fair an lawful way
2. data must only be used for the stated purposes
3. data must be adequate relevant and non excessive
4. data must be accurate
comp 1.6: what is the computer misuse act of 1990
it forbids people to access a computer without authorisation, it is also illegal to modify destroy or access data or accounts physically or through the internet
comp 1.6: what is the copyright designs and patents act of 1988 and what is it illegal to do under the act
copyright affects all creative work and requires no registration
under the act it is illegal to
- make copies
- share the material
- use unlicensed software
- plagiarise creative work
patents are legal protections of work
comp 1.6: what is the freedom of information act of 2000
a public body is an organisation that provides a public service
the FOI act dictates that regulatory bodies must regularly publish certain info. info that can be requested includes:
- activity logs
- financial information
- statistics
- CCTV
comp 1.6: what is the computer misuse act of 2018
The Computer Misuse Act defines the following as illegal and will prosecute: Unauthorised, or malicious, access to material stored on a computer. Intentional harm, or crime, using computer systems. Modifying, removing, or ransoming data.
comp 1.1: what happens in the first stage of the FDE cycle
During the first stage of the FDE cycle the instruction is Fetched from primary storage and its location stored in the MAR
comp 1.1: what happens in the second stage of the FDE cycle
during the decode stage of the FDE cycle the CU interprets the instruction then code for the instruction is fetched from memory
comp 1.1: what happens in the third stage of the FDE cycle
the operation is performed
comp 1.1: what are the 3 factors that affect CPU performance
- clock speed
- cores
- cache memory
comp 1.3: what are 4 properties of flash memory
- non-volatile
- short lifetime
- fast access
- robust, it has no moving parts
comp 1.2: what are some drawbacks of virtual memory
- negative impacts on performance
- negative impacts on health of SSD
- there might be limited space in secondary storage
comp 1.2: what is paging in terms of virtual storage
- memory can be split into ‘pages’
- virtual memory works by moving these pages into secondary storage when they are not in use
- when they page is required again it needs to be moved back into the ram
comp 1.2: what is 2 bits called
a crumb
comp 1.2 what is 4 bits called
a nibble
comp 1.2: what is 8 bits called
a byte
comp 1.2: what happens when you shift binary to the left
you multiply by 2
comp 1.2: what happens when you shift binary to the right
you divide by 2
comp 1.2: how is a bit stored in magnetic storage
it is represented by a positively or negatively charged magnetic particle, these particles are part of a disk called a platter
comp 1.2: what are 4 properties of magnetic storage
- low cost
- low speed
- good reliability
- high capacity
comp 1.2: what are 4 properties of optical storage
- low cost
- low capacity
- low speed
- great reliability, waterproof, shockproof
comp 1.2: what are the things that CD-R, DVD-R and BD-RW have in common
- they are optical storage
- they can only be written to once, the R part
comp 1.2: how do you convert from binary to hexadecimal
- group the binary into 4 bits
- covert these bits to denary
- convert this number into hex
comp 1.2: what is 1100 in hexadecimal
C
comp 1.2: what is 0101 in hexadecimal
5
comp 1.2: what is 101 in hexadecimal
5
comp 1.2: what are 2 uses of hex
- HTML colors
- MAC address
comp 1.2: what happens when you add binary 0 + 0
0
comp 1.2: what happens when you add binary 0 + 1
1
comp 1.2: what happens when you add binary 1 + 1
0 and carry over the 1
comp 1.2: what are overflow errors and when do they occur
binary numbers are stored at a fixed length, when adding, if this length is exceeded an overflow error occurs, they lead to inaccurate results to calculations
comp 1.2: what does ASCII stand for
American Standard Code for Information Interchange
comp 1.2: how many different characters does ASCII store
128
comp 1.2: what are the differences between Unicode and ASCII
Unicode uses can represent 32 bits and aims to represent every character in the world, even emojis, and ASCHII uses only uses 8 bits
comp 1.3: what 4 things effect network performance
- bandwidth
- wired or wireless
- hardware
- topology
comp 1.3: what is packet switching
it is the process of breaking down data into packets, sending them across the internet and then re-assembling at the destination
comp 1.3: in star network topology, what are all of the clients connected to
server or switch
comp 1.3: how many channels are there in the 2.4 GHz band
13
comp 1.3: how many channels are there in the 5 GHz band
24
comp 1.3: what is a static IP adress
an IP that does not change every time the device connects to the network
comp 1.3: what is a dynamic IP adress
it is a device that’s IP changes every time it connects to a network
comp 1.3: what is a public IP address
an IP seen on the WAN
comp 1.2: how to convert hexadecimal 7C into denary
(16 x 7) + (12(C) x 1) = 124
comp 1.2: how many colours can be stored in a 7 bit binary number
129
comp 1.3: what is an ipv4 adress
4 max 255 digits e.g. 192.16.8.223
comp 1.3: what is an ipv6 adress
IPv6 addresses are 128-bit numbers, often displayed as eight groups of four hex digits. For example: 2001 : 0db8 : 85a3 : 0000 : 0000 : 8a2e : 0370 : 7334
comp 1.3: what is a Mac address (example)
MAC addresses are represented as pairs of hexadecimal digits. For example: B8:8D:12:58:77:32
comp 1.3 what is the role of a switch in a star topology
- it connects all of the devices on the network together
- revieves all of the data from the network
- uses the mac adress of the devices
comp 1.2: what frequency is cd sampled at
44.1 kHz
comp 1.2: how to you calculate the size of a text file
text filve size = avarage bits per character x number of characters
comp 1.3: what is an example of a mac adress
00-B0-D0-63-C2-26
Clarify tcp up model
