⌨️Computer Science 1 Flashcards
Paper 1 and 2
1
Q
comp 1.5: what are the 3 types of system software
A
utility/application software, device drivers, operating software
2
Q
comp 1.5: what does the operating system do
A
a piece of software that controls system hardware, it has mangers for each piece of hardware
3
Q
comp 1.5: name all of the managers used by the operating system
A
memory manager, user manager, process manager, file manager
4
Q
comp 1.5: what is a CLI
A
it is a command line interface
4
Q
comp 1.5: what is a GUI
A
it is a graphical user interface
5
Q
comp 1.5 what is a WIMP
A
stands for Windows Icons Mice and pull down menus, it is a system of software features designed to simplify system operation for the user
5
Q
comp 1.5: name 4 types of utility software
A
defragmentation, encryption, compression, backup
6
Q
comp 1.5: what is a single user OS
A
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
7
Q
comp 1.4: what is social engineering
A
someone being influenced into giving away info that could grant access to accounts
8
Q
comp 1.4: what is an insider attack
A
it is an attack by someone on the inside where the give away vunerable info
8
Q
comp 1.4: what is an active attack
A
using a technical method, such as malware or other to compromise a networks security
8
Q
comp 1.4: what is a passive attack
A
this is an attack where attackers eavesdrop by ‘sniffing’ data packets
8
Q
comp 1.4: what is a penetration test
A
this is where an organization performs a controlled attack on itself to identify its weak spots, this can be performed by ‘ethical hackers’
9
Q
comp 1.4: name all of the types (7) of malware
A
- 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
10
Q
comp 1.4: what are firewalls and what do they do
A
they are either hardware or software that ‘sits’ between the user and the internet that filter packets
10
Q
comp 1.4: what are the 4 types of active attacks
A
- 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
10
Q
comp 1.4: what methods do firewalls use to filter packets
A
- 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
11
Q
comp: what is a protocol
A
a set of rules for transferring data
11
Q
comp 1.4 what are the 4 methods of data interception
A
- 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
11
Q
comp 1.4: what are botnets
A
they are many machines infected with malware that can be used for DDoS attacks
11
Q
comp 1.3: what is a switch in networks
A
it is a device that connects serval devices to make a wired network
11
Q
comp 1.3: what is a network layer
A
they break up the sending of packets into different components, each component handles a different part of the communication(TCP/IP model)
12
Q
comp 1.3: what is a NIC
A
a network interface controller is a device that provides connection between a device and the network
13
Q
comp 1.3: what is a router
A
this is a piece of hardware that connects networks together
14
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
15
comp 1.3: what is a twisted pair cable
ethernet cable, made of eight wires twister into pairs to reduce interference
16
comp 1.3: what is a LAN
local area network
16
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
17
comp 1.3: what is a WAN
wide area network
18
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
19
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.
20
comp 1.3: what are the advantages of the pier to pier server model
cheaper, more robust, and it commonly used for streaming
21
comp 1.3: how does the internet work
| DNS
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
22
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
23
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
24
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
25
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
26
comp 1.3: what is WEP
wired equivalent protection is the weakest protection and is protected by one password
27
comp 1.3: what is WPA protection
WIFI protected access is better than WEP, it uses one password and encryption
28
comp 1.3: what is WPA2 protection
WIFI protected access v2 is better WPA bc it uses better encryption
29
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
30
comp 1.3: what is the ethernet protocol
this is a protocol that defines how data should be transmitted over a cable
31
comp 1.3: what is the TCP
- Transmission control protocol
- it is responsible for making sure that communication between 2 routers is error free
32
comp 1.3: what is the cloud
these are large datacentres
33
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
34
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
35
comp 1.3: what is HTTP
hypertext transfer protocol is a protocol that determines how data is transferred between browser and web server
35
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
36
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
37
comp 1.3: what is HTTPS
HTTPS is secure HTTP that uses SSL (secure socket layer) in order to encrypt the data
38
comp 1.3: what is SMTP
simple mail transfer protocol determine how email data is sent from clients to servers
39
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, the server deletes the email when it is downloaded by the user, only the local copy remains
40
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
41
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
42
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
43
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
44
Comp 1.1: what is the ACC
The accumulator hoods the results of calculations
45
Comp 1.1: what is the ALU
The algorithmic logic unit performs calculations
46
Comp 1.1: what is the control unit
The control unit decodes instructions and signals to control how data moves around the CPU
47
Comp 1.1: what does the cache do
Stores commonly used instructions so they are faster to execute
48
Comp 1.1: what do registers do
Registers store small amounts of data needed for processing, they are very fast
49
Comp 1.1: what are the 4 types of register in the CPU
MAR, MDR, PC, ACC
50
Comp 1.1: what is primary memory
RAM
51
Comp 1.1: what is BIOS and what does it stand for
Basic Input/Output System
The basic firmware that is embedded in the computer ROM chip used to start a computer. is an example of a program that is stored in ROM. The BIOS runs as soon as the computer is switched on.
52
Comp 1.2: what does the rom do
Read only memory, this helps to wake up the computer and performs the post cycle
53
Comp 1.2: what is virtual memory
When to computer runs out of primary storage it can make up for this with secondary storage
54
Comp 1.2: what are the 3 types of secondary storage
Magnetic, optical, solid state
55
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
55
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
55
comp: what is a url
this is a uniform recourse locator and it is contains info about the location of the webpage
55
comp: what is a intranet
a local restricted communication network
56
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
- it can be used for text files and image files, where it is crucial to preserve all of the original data
57
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
58
comp 1.2: what is compression
it is a method that is used to reduse file size
59
comp 1.2: what is bit depth in sound storage
it determines the number of amplitudes values can be stored per sample
60
comp 1.2: what is sampling in audio storage
where the mic measures the audio a certain amount of times a second
61
comp 1.1: what are the 4 registers in the cpu
MDR, MAR, ACC, PC
62
comp 1.1: what 2 parts of the FDE cycle does the control unit perform
fetches the instruction
decodes the instruction
63
comp 1.1: what 2 parts of the FDE cycle does the ALU perform
- it performs arithmetic and logical calculations
- it acts as a gateway between primary and secondary storage (data that is transferred between them passes through the ALU)
64
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
65
comp 1.1: what are the steps of the FDE cycle
Fetch decode execute
66
comp 1.1: what does the control bus do
it carries control instructions
67
comp 1.1: what does the data bus do
it carries data
68
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
69
comp: what is a modem
the modem takes signals from the ISP and changes them into signals that your devices can interpret
70
comp: how do you prevent data interception
you use encryption to make the data safe
71
comp: what is a macro
it is a piece of software that is given permission to run by the user
72
comp: what is 2fa
two factor authentication, it requires to forms of authentication to provide access
73
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
74
comp: what do registers do
store small amounts of data used when processing
75
comp: what does cache do
stores commonly used instructions, it makes the cpu faster
75
comp: what is pseudocode
it is fake code that makes development easier
76
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
77
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
78
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
79
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
80
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
81
comp 1.6: what is the data protection act of 2018
It replaced the data protection act of 1988 and defined how companies handled your data, check
82
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
82
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
83
comp 1.1: what happens in the third stage of the FDE cycle
the operation is performed
84
comp 1.1: what are the 3 factors that affect CPU performance
- clock speed
- cores
- cache memory
85
comp 1.3: what are 4 properties of flash memory
- non-volatile
- short lifetime
- fast access
- robust, it has no moving parts
86
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
87
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
88
comp 1.2: what is 2 bits called
a crumb
89
comp 1.2 what is 4 bits called
a nibble
90
comp 1.2: what is 8 bits called
a byte
91
comp 1.2: what happens when you shift binary to the left
you multiply by 2
92
comp 1.2: what happens when you shift binary to the right
you divide by 2
93
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
94
comp 1.2: what are 4 properties of magnetic storage
- low cost
- low speed
- good reliability
- high capacity
95
comp 1.2: what are 4 properties of optical storage
- low cost
- low capacity
- low speed
- great reliability, waterproof, shockproof
96
comp 1.2: what are the things that CD-R, DVD-R and BD-R have in common
- they are optical storage
- they can only be written to once, the R part
97
comp 1.2: how do you convert from binary to hexadecimal
1. group the binary into 4 bits
2. covert these bits to denary
3. convert this number into hex
98
comp 1.2: what is 1100 in hexadecimal
C
99
comp 1.2: what is 0101 in hexadecimal
5
100
comp 1.2: what is 101 in hexadecimal
5
101
comp 1.2: what are 2 uses of hex
- HTML colors
- MAC address
102
comp 1.2: what happens when you add binary 0 + 0
0
103
comp 1.2: what happens when you add binary 0 + 1
1
104
comp 1.2: what happens when you add binary 1 + 1
0 and carry over the 1
105
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
106
comp 1.2: what does ASCII stand for
American Standard Code for Information Interchange
107
comp 1.2: how many different characters does ASCII store
128
108
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
109
comp 1.3: what 4 things effect network performance
- bandwidth
- wired or wireless
- hardware
- topology
110
comp 1.3: what is packet switching
Packet switching is the process of breaking data down into packets, sending them across the Internet to another computer, and then re-assembling the data.
111
comp 1.3: in star network topology, what are all of the clients connected to
server **or** switch
112
comp 1.3: how many channels are there in the 2.4 GHz band
13
113
comp 1.3: how many channels are there in the 5 GHz band
24
114
comp 1.3: what is a static IP adress
an IP that does not change every time the device connects to the network
115
comp 1.3: what is a dynamic IP adress
it is a device that's IP changes every time it connects to a network
116
comp 1.3: what is a public IP address
an IP seen on the WAN
117
comp 1.2: how to convert hexadecimal 7C into denary
(16 x 7) + (12(C) x 1) = 124
118
comp 1.2: how many colours can be stored in a 7 bit binary number
128 obv
119
comp 1.3: what is an ipv4 adress
4 max 255 digits e.g. 192.16.8.223
120
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
121
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
122
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
123
comp 1.2: what frequency is cd sampled at
44.1 kHz
124
comp 1.2: how to you calculate the size of a text file
text filve size = avarage bits per character x number of characters
125
comp 1.3: what is an example of a mac adress
00-B0-D0-63-C2-26
144
Clarify tcp up model
145
Comp: what does the ROM do
It holds the boot up program
146
Comp: what factors make the advantages and disadvantages of different forms of storage
- capacity
- speed
- portability
- durability
- reliability
- cost
147
Comp: when doing storage conversions what value other than 1000 (such as mb to GB) can be used
1024
148
Comp: how do you calculate sound file size
Soude file size = sample rate x duration (s) x bit depth
149
Comp: how do you calculate image file size
Image file size = Colour depth x image height (px) x image width (px)
150
Comp: how do you calculate text file size
Text file size = bits per character x number of characters
151
Comp: what is the denary number range in comparison to hex and binary
- denary 0-255
- hexadecimal 00 - FF
- binary 00000000 - 11111111
152
Comp: what is the most significant bit
The bit with the highest positional value (either one or 0) basically the one on the left
153
Comp: what is the least significant bit
It is the bit with the least value, the one on the right basically
154
Comp: what is a character set
A collection of characters used to represent text in a computer system
155
Comp: what are the 2 types of character sets that you must know
- unicode
- ASCII
156
Comp: how many bits does binary use to represent ASCII
8 bits
157
Comp: how are character sets ordered
The character code for 'b' will be one more that the character code for 'a'
158
Comp: what is the colour depth
It is the number of colours that can be displayed in an image
159
Comp: what is resolution
The 'resolution' of an image is the word used to describe how tightly packed the pixels are
160
Comp: what is sample rate and what is it measured in
It is the number of samples per second measured in Hz check
161
Comp: when storing sounds what must be done (to make a digital sound)
The **analog** sounds must be converted into binary
162
Comp: what is the bit depth of an sound file
The number of bits used to represent each sample of audio
163
Comp: what is the duration of a sound file
How long it is
164
Comp: what is metadata
It stored additional image information e.g. height, width, ect
165
Comp: what is a mode of wired connection
ethernet
166
Comp: what is a mode of wireless connection
- wifi
- Bluetooth
167
Comp: what does a web server provide and what does a file server provide
- web server - web pages
- file server - file storage/retreval
168
Comp: what is a DNS made up of
Multiple domaine name servers
169
Comp: what is the internet
It is a network of computer networks
170
Comp: what is the hardware needed to connect stand alone computers (wirelessly) to a LAN (5 things)
- wireless access points
- routers
- switches
- network interface controller/card
- transmission media
171
Comp: what networks does the internet contain
- **D**omaine **n**ame **s**ervers
- hosting
- the cloud
- web servers and clients
172
Comp: what are transmission media
Signals from one computer to another check
173
Comp: what are standards
a set of guidelines that when used with different hardware and software allows them to work with each other (compatibility) and allow data exchange (interoperability)
174
Comp: what are common prevention methods (for malware check)
- penetration testing
- anti-malware software
- firewalls
- user access levels
- passwords
- encryptions
- physical security
175
Comp: what are the things that memory management does
- transfers data between memory
- the allocation of memory
- how it allows multitasking
176
Comp: what are the things that file management does
- naming
- allocating folders
- moving files
- saving
177
Comp: what are the things that user management does
- allocation of an account
- access rights
- security
178
Comp: when data is transferred between the devices and the processor what must be done
The process must be managed
179
Comp: what are the impacts of technology on wider society
- ethical issues
- legal issues
- cultural issues
- environmental issues
- privacy issues
If one of these is not understood look it up
180
comp: if there is a 2ghz process or with 4 cores what is the clock of each core
0.5 ghz
181
comp: what do the 128 characters in ascii include
- 32 control codes (mainly to do with printing)
- 32 punctuation codes, symbols, and space
- 26 upper case letters
- 26 lower case letters
- numeric digits 0-9
182
comp: what is extended ASCII
it is ASCII with 256 characters (special characters)
183
comp: what is MSB
most significant bit
184
comp: what is LSB
least significant bit
185
comp: what is a NIC used to connect to a wireless network
wireless NIC, set as 4 if know
186
comp: what protocol is used to transmit an encrypted website from website to server
HTTPS
187
Comp: what are the 2 software licenses that you must know about
- proprietary
- Open source
188
Comp: what is a Mac address assigned to devices for use in
In a network
189
Comp: what do standards allow
Hardware/software to interact across different manufactures/products
190
Comp: what is a communication protocol
It is a set of rules for transferring data
191
Comp: what are layers, check
In networking, layering means to break up the sending of messages into separate components and activities
192
Comp 1.3: what stack does the TCP form
The TCP/IP protocol stack
193
comp1.3: what does the TCP/IP protocol stack do
It enables communication across the internet
194
Comp: what is secondary storage
It is non volatile storage for long term retention/storage of files
195
Comp: what is primary storage
Part of the computer that holds data while it is in use
196
COMP: what is an embedded system
197
Comp: with regards to networks what is layering
In networking, layering means to break up the sending of messages into separate components and activities. Each component handles a different part of the communication. This can be referred to as the Transmission Control Protocol/Internet Protocol (TCP/IP) model.
198
Comp: proa and cons of network layers
199
Comp: how do hard drives get fragmented
200
Comp: how many unique values can be represented by 4 bits
16 (because 0 counts)
201
Comp: how can more devices using a network at the same time affect its performance
- there will be a slower transmission of data
- more data is being transmitted
- devices have to wait longer before they can transmit
- more bandwidth will be used and so it is split between the devices when they are sending data
