Paper 1 Flashcards
(116 cards)
1
Q
what does a computer system consist of?
A
hardware and software that works together
2
Q
what is an embedded system?
A
computer inside a larger system
3
Q
feature of embedded systems and why?
A
because they only do 1 task, they’re usually cheaper, more efficient and easier to design
4
Q
name 5 main hardware components?
A
- motherboard
- optical drive
- ram sticks
- CPU
- hard disk drive
- power supply
- graphics card
- case cooling fan
5
Q
what does the CPU do?
A
processes data and instructions that make the system work
6
Q
what does CPU architecture describe?
A
the main CPU components, how they interact with eachother and other parts of the computer system
7
Q
name 3 features of the control unit?
A
- manages fetch-execute cycle of program instructions
- in overall control of the CPU
- controls flow of data inside and outside the CPU
8
Q
3 features of the arithmetic logic unit?
A
- does all calculations
- performs AND, OR, NOT operations and binary shifts
- contains the accumulator register in the CPU
9
Q
4 features of cache?
A
- high-speed memory in CPU, slower than registers but faster than RAM
- stores regularly used data, so it can be accessed quicker when needed
- low capacity and expensive
- 3 levels, L1, L2, L3
10
Q
What is von neuman architecture?
A
a system where CPU runs programs from memory
11
Q
2 feature of the program counter
A
- in control unit
- holds the memory address of the instruction for each cycle
12
Q
what does the accumulator do?
A
stores intermediate results from the ALU
13
Q
what does the memory address register do?
A
holds any memory address’s about to be used by the CPU
14
Q
what does the memory data register do?
A
holds the actual data or instruction
15
Q
what cycle does the CPU follow?
A
fetch - execute cycle
16
Q
2 steps of fetching?
A
1) copy memory address from PC to MAR
2) copy the instruction from the MAR address to the MDR
17
Q
what happens when decoding?
A
instruction in the MDR is decoded by the control unit
18
Q
what is RAM?
A
high speed, volatile, main memory
19
Q
what is main memory?
A
where everything is stored while being used
20
Q
when do things leave RAM?
A
when they’re closed
21
Q
what happens when the computer boots up?
A
the operating system is copied from the ROM to the RAM
22
Q
what is virtual memory?
A
secondary storage used as extra RAM
23
Q
when is virtual memory used?
A
when RAM is full
24
Q
what does ROM do?
A
tells the CPU how to boot up
25
where is ROM?
comes on a small chip in the motherboard
26
what is primary storage?
any memory areas the CPU can access quickly
27
how is data stored on a hard disk drive?
magnetically
28
what is the traditional storage medium?
HDD
29
4 features of HDD's?
- high-capacity
- reliable
- cheaper
- longer read/write life
30
4 features of SSD's?
- fast
- doesn't need defragmenting
- silent
- more shock-proof
31
what are solid state drives?
fast, reliable secondary storage
32
what are optical disks?
cheap, robust secondary storage
33
what are the 3 forms of optical disks?
- read-only
- write-only
- rewritable
34
3 features of optical disks?
- cheap
- portable
- shock and water proof
35
what are magnetic tapes used for?
archiving
36
name all 8 units in order, smallest first?
- bit
- nibble
- byte
- KB
- MB
- GB
- TB
- PB
37
how many bits in a nibble?
4
38
how many bits in a byte?
8
39
what are character sets?
a collection of characters that a computer recognises from their binary representation
40
why must characters be converted?
computers can only process binary
41
what are the 2 character sets?
- ASCII
| - unicode
42
which is the most commonly used character set?
ASCII
43
how many bits are used to represent ASCII?
7-bit binary, but aa 0 is added infront so it fits into 1 byte
44
what is the calculation for file size of characters?
num of bits per character X num of characters
45
what are images stored as ?
a series of pixels
46
what is the colour of a pixel represented as?
a binary code
47
how many bits per pixel are needed for a black and white image?
1
48
how can you make a greater range of colours and shades per pixel?
increasing number of pits per pixel
49
what is the calculation for number of colour in an image?
2 (to the power of number of bits per pixel)
50
what is colour depth?
number of bits per pixel
51
what is image resolution?
number of pixels in an image
52
what are the 2 calculations for file size of an image?
image resolution X colour depth
| - width X height X colour depth
53
what is metadata?
information about the image
54
what is sound recorded as?
an analogue signal
55
what is an analogue signal?
pieces of continually changing data
56
what is sampling?
converting analogue to digital
57
name 2 factors that affect sound file size and quality?
- bit depth
| - sample rate
58
what is bit depth?
bits available for each sample
59
what is sample rate?
how many samples taken per second
60
calculation for sound file size?
sample rate X bit depth X length
61
what does increasing bit depth do?
means digital files can pick up lower sounds
62
what is data compression?
when a file size is made smaller, while being tru to the original
63
4 advantages of data compression?
- files take up less storage
- streaming and downloading is quicker
- web pages load quicker
- file can fit email service restrictions on file size
64
what is lossy compression?
works by permanently removing data from the file
65
what is losseless compression?
temporarily removes data to store the file, and then restores it to the original when opened
66
name 3 pros of lossy compression?
- greatly reduced file size, so more files can be stored
- commonly used, can be read
- take up less bandwidth, so can be downloaded quicker
67
name 2 pros of lossless compression?
- no reduction in quality
| - can be used in text or software files
68
name 3 cons of lossy compression?
- file loses data
- cant be used on text or software files
- worse quality than original
69
name a con of lossless compression?
only slightly reduced file size, so still takes up quite a bit of space
70
name 3 pieces of network hardware?
- network interface controller
- switches
- routers
71
what is a network interface controller?
an internal piece of hardware built into the motherboard that allows a device to connect to a network
72
name 2 things switches do?
- connect devices on a LAN
| - recieve data from 1 device and transmit it to another on the network
73
name 3 things routers do?
- transmit data across networks
- on the internet, they direct data to their destination
- connect LANS to the internet
74
name the 2 types of basic cable?
- cat 5
| - cat 6
75
name the 2 types of advanced cable?
- coaxial cable
| - fibre optic cable
76
name 3 features of fibre optic cables?
- transmit data as light
- very expensive
- very high performane
77
describe the structure of coaxial cables?
a single copper wire surrounded by plastic insulation and metal mesh to stop interferance
78
does wifi have a high or low bandwidth, compared to bluetooth?
high bandwidth
79
what is a network protocal?
a set of rules for how devices communicate
80
what addresses does communication over the same network use?
MAC address
81
what addresses does communication over different networks use?
IP address
82
how are MAC addresses assigned?
assigned by the manufactuer
83
how are IP addresses assigned?
assigned manually or automatically before a device can access a network
84
why are MAC addresses needed?
so they have a unique identifier that can be found on the internet
85
how are MAC addresses displayed?
- either 48 or 64 bit binary code
| - converted to hex for ease
86
what addresses are used when sending data over the internet?
IP address
87
what does the TCP do?
sets rules for how devices connect on the network. in charge of splitting data into packets and reassembling after theyve been sent
88
what does the IP do?
responsible for directing packets to their destination across the network
89
what is HTTP used for?
used by web browsers to access websites and servers
90
what is HTTPS used for?
a more secure version of HTTP
91
what is FTP used for?
to access, edit and move files between devices on a network
92
what is POP3 used for?
to retrieve emails from a server. the server holds the email until you download it, then its deleted from the server
93
what is IMAP used for?
to retrieve emails from a server
94
what is SMTP used for?
to send emails
95
how many network protocol layers are there?
4
96
what does network protocol layer 1 cover?
passing data over the physical network
97
what does network protocol layer 2 cover?
making connections between networks and directing data
98
what does network protocol layer 3 cover?
controlling data flow
99
what does network protocol layer 4 cover?
turning data into websites and other applications
100
name 2 advantages of using layers?
- breaks network communication into manageable pieces
| - changing 1 layer wont affect others, as they are self contained
101
name 5 types of network attacks?
- passive attack
- active attack
- insider attack
- brute force attack
- denial of service attack
102
what is malware?
software that can harm devices
103
name 5 typical actions of malware?
- deleting or changing files
- scareware
- locking files
- spyware
- opening backdoors
- rootkits
104
name 3 types of malware?
- viruses
- worms
- trojans
105
what is the difference between worms and viruses?
worms self-replicate without user help
106
what is social engineering?
a way of gaining information on or illegal access to networks by influencing people
107
what is phishing?
a type of social engineering that involves criminals sending emails to trick people
108
name 6 malware prevention methods?
- penetrative testing
- physical testing
- passwords
- user access levels
- anti-malware software
- encryption
109
what is a client-server network?
network that is managed by a server and the devices connected are clients
110
what is a peer-peer network?
network where all devices are equal and are connected to eachother
111
describe a mesh topology?
where all devices are connected to eachother
112
describe a star topology?
all devices are connected to a central switch or server
113
describe a bus topology?
all devices are in a line and are connected to a single backbone cable
114
describe a ring topology?
data moves in one direction around the ring to avoid collisions
115
what is a VPN?
a private network deployed over the internet
116
what is DNS?
a name database in which domain names are converted to IP addresses
