EVERYTHING Flashcards
(100 cards)
1
Q
What is the CPU?
A
It is a component that carries out program instructions using data
2
Q
What is inside the CPU?
A
ALU, CU, Cache, Registers
3
Q
ALU = ?
A
Arithmetic Logic Unit, Carries out maths and logic calculations
4
Q
CU ?
A
Control unit, coordinates the F-E cycle. Decodes instructions.
5
Q
What is Cache?
A
Small, fast memory that holds frequently accessed items.
6
Q
Registers (4)
A
MAR, MDR, PC, ACC
7
Q
MAR?
A
Memory address register, holds address of memory being fetched / written to
8
Q
MDR?
A
Memory data register, Instruction that has been fetched / written to
9
Q
pc?
A
Program counter, address of next instruction to be fetched from memory
10
Q
ACC?
A
Accumulator, holds all results from ALU calculations
11
Q
What architecture is used in most PCs?
A
Von Neumann architecture has all these components and is used in most PCs
12
Q
FDE Cycle?
A
Fetch Decode Execute Cycle, controlled by the CU. Instructions are fetched from RAM to be decoded and executed by CPU
13
Q
Step 1 of FDE Cycle
A
PC displays address in RAM of next instruction to be processed.
Value is copied into MAR
14
Q
Step 2 of FDE Cycle
A
PC increases by 1, which prepares CPU for next instruction to be fetched.
15
Q
Step 3 of FDE Cycle
A
CPU checks address in RAM which matches with address in MAR
16
Q
Step 4 of FDE Cycle
A
instruction in RAM is transferred to MDR
17
Q
Step 5 of FDE Cycle
A
instruction in MDR copied into CIR
18
Q
Step 6 of FDE Cycle
A
Instruction in CIR is decoded and executed. Any result is stored in the accumulator.
19
Q
What is clock speed?
A
rate at which the F-E cycle is carried out (GHz)
20
Q
Why clock speed higher better?
A
more cycles/second, faster rate of instructions being carried out on data, faster computer.
21
Q
Why number of cores bigger better?
A
If software allows it, each core can execute an instruction at the same time. Instructions faster
22
Q
Why big cache good?
A
More regularly used items can be held, reducing reliance on the slower RAM.
23
Q
what is embedded system?
A
Computers inside other devices that are simple and usually have one purpose only.
24
Q
4 examples of embedded system
A
Smartwatches
Fitness trackers
Traffic lights
Washing Machines.
25
Primary vs Secondary storage?
Primary storage is directly accessible by the CPU, is volatile, and has a smaller capacity. Secondary storage is not directly accessible by the CPU, is non-volatile, and has a larger capacity, primary storage is faster than secondary storage.
26
2 Primary storage examples.
RAM, ROM
27
explain virtual memory
when RAM is full, part of secondary storage may be used as virtual memory. (IT SLOWS DONW PC IF YOU HAVE TO USE IT)
28
ROM VS RAM?
Ram = volatile, holds open programs and data
ROM = non-volatile, contains program that runs when computer boots (BIOS) which loads OS from storage into RAM
29
3 types of Secondnary storage + examples
Magnetic - HDD
Optical - DVD
Solid state - SSDs
30
explain 3 types sec storage work
Magnetic - uses different levels of magnetic polarity
Optical - uses diff refl. of light
Solid state uses electronic circuitry
31
Magnetic adv and disadv
Reliable, cheap (cheapest gb/$, with large capacity
Not very durable and the spinning disk makes noise.
32
Optical adv and disadv
Portable & reliable but not durable, low capacity/disc
33
Solid state adv and disadv
Fastest read/writespeeds and very durable. Very expensive
34
A binary shift to the left of 1 would?
Double the value
35
A binary shift 1 to the right would?
Halve it and loses least important bit
36
Character set is? (W examples)
A group of character codes
ASCII, Unicode
37
Room for ASCII/Unicode
ASCII has 8 bits per character, room for 2^8 which is 256 diff characters.
Unicode has atleast 16 bits / character, can represent thousands of characters.
38
What is resolution?
num of pixels
39
What is colour depth? what is the color depth for an image with 256 dff colors?
Bits/pixel
2^8 = 256
8 bits/pixel
40
How do computers record sound?
They record samples of the amplitude taken at regular time intervals. (256Hz, 444Hz, etc etc)
41
What is sample rate & bit depth?
Sample rate is samples/second (Hz)
Bit depth = bits/sample
42
Why do we compress files?
Reduce file size to take up les storage space and for shorter transmission times.
43
Lossy compression?
deletes parts of file permanently, causing file to be smaller in quality and size. (Good for image/sound, bad for text.)
44
Lossless compression?
Presents file more efficiently. (Good for word/program files, not as efficient as lossy for audio/image)
45
LAN?
Local area network
small geographical area
(School network)
46
WAN?
Wide area network
infrastructure owned by multiple entities (Internet)
47
Client-server relationship?
Clients request, servers respond, the server acts as a central control
48
Peer-to-peer relationship?
All devices can be both client and server, they also all connect independently.
49
Star topology (def. + adv. + disadv.)
Type of network structure where all devices are connected to a single node.
They rely on the central node (if it fails, everything fail)
Easy to add new devices.
50
Mesh topology (def. + adv. + disadv.)
A network structure where all devices are interconnected to each other.
Difficult to install new devices
more stable
High performing - few collisions
51
kinds of central devices in a network
WAP - Wireless
Router - forward packets IN A network
NIC - used to connect to a network (connect transmission mediums like ethernet from and to computer and router)
Switch - like router but within a network, uses MAC address to make sure packets go right way.
Mac address = unique worldwide hardware address every NIC has so it pinpoint currect device in a network.
52
What is bandwidth?
Maximum amt of data that can be transferred at a time
Has to be shared across all devices transmitting
More devices transmitting = collisions are more likely (errors)
53
what is IP address? (2 types also)
Locates devices on internet geographically.
IPv4 - 128.10.2.255
IPv6 - 71C1:201D:ABC1:FFFF:10A9:0:44C:FF0F
54
Describe packet use.
When we send data over networks, it splits into many different packets because it is easier to break up and send and receive and build again than to send a massive packet which could fail.
55
Describe what is in a packet.
Packet Destination, IP Address, data
56
what is DNS?
when a URL is entered, a DNS server looks up its IP address
https://google.co.uk
https://74.125.224.72
57
What are the cloud servers?
They are servers that host resources or files that can be accessed through the internet
58
Cloud servers (adv. + disadv.)
Host large amt of files
Be accessed anywhere
relatively cheap compared to storing locally on HDDs
---
They can be hacked into if they know your password
Must have internet
Still costs money in the form of a monthly subscription
59
What is a protocol?
A set of rules enabling devices to communicate
60
What is layer (protocols)
A group of protocols that perform similar functions.
61
What are standards? (Protocols)
Agreed rules by manufacturers that ensure device compatibility when discussing protocols.
62
TCP/IP and FTP protocol?
Transmission control protocol splits data into packets and handles errors
Internet protocol assigns IP addresses
FTP is a way to transmit files over computers through TCP/IP connections.
63
Email protocols uses?
IMAP & POP are used to receive emails and SMTP is used to send
POP doesnt sync to a server while IMAP syncs with a mail server.
SMTP simply sends an email to another email address.
64
Email protocols? (Names)
POP - Post office protocol
IMAP - Internet message access protol
SMTP - simple mail transfer protocol
65
How can data be sent through a network?
Wireless (WiFi, Bluetooth) and Wired (Ethernet)
66
Wireless/Wired Adv. + Disadv.
Wireless - Reliable and faster but less flexible, expandable and movable
Wired - More portable, convenient, scalable but more interference, less security and range and less bandwidth
67
Cyberattacks (5)
SQL injection
Brute-force
DoS
Social engineering
Malware
68
What is SQL injection?
Controlling database via user input, fixed by validating user input
Ex.
Enter Username
Deleteserver()
69
What is Brute-force?
Trying every password combination, fixed with long passwords or limit on attempts.
70
What is DoS
Denial of service
Flooding a device with traffic causing it to crash.
71
What is social engineering?
Tricking humans to give info
Phishing websites fixed by training or general awareness.
72
What is malware?
Malicious software e.g. viruses
73
How do you prevent viruses? (6)
Penetration teting
Firewalls
Physical security
Anti-Malware
Encryption
User access levels
74
What is penetration testing?
Simulating an attack to find issues and fix them
75
What is firewall?
A Hardware/software component that checks all ingoing/outgoing packets. They can be blocked if they dont meet a rule.
76
What is physical security?
CCTV Locks Security staff
77
What is Anti-Malware
Scans for known software and removes it
78
what are user access levels?
Putting in level of access to who can read/write to what file
79
What is encryption?
Scrambling data so only those with a key can decrypt data and understand the text.
80
What do OS manage?(5)
UI (GUI/CLI)
Memory
Peripherals
Users
Files
81
How do OS manage memory?
deciding / controlling the transfer of files from primary storage to secondary storage before being executed.
82
How do OS manage Peripherals (what are they too)
Peripherals - external devices such as headsets, printers, keyboards
Drivers that help communicate between devices is controlled by OS
83
How do OS manage users/files?
Most OS allow the use of multiple user profiles and they control the partitioning of files and the password system
84
What is fragmentation?
When there are so many files on a disk that they are now separated across it - slowing it down as now the read/write head needs to move farther to access different parts of a program in a disk.
85
what is defragmentation?
Utility software that reorganizes the disk.
86
3 kinds of utility software
Encryption, data compressions and defragmentation
87
3 laws you need to know
Data protection act 2018
Computer misuse act of 1990
Copyright, Designs and Patents Act of 1988
88
What is Data protection act of 2018
Uk updated DPA (1998) into DPA (2018)
Each person who has data stored is a data subject and the orginastion is the data controller who is responsible for registering with the information commisioner.
THERE ARE 6 PRINCIPLES
89
What are the 6 principles of the DPA 2018?
1. Collected lawfully and processed fairly
2 only used for reasons specified
3. Data must be relevant not excessive
4. Data must be accurate and up-to-date
5. Data must not be stored longer than necessary
6. Data must be stored and processed securely
90
What is the computer misuse act of 1990?
The act attempts to stop and punish those who use computers inappropriately. Breaking any of the three principles could result in fines and a jail sentence
1. No unauthorised access to data
2. No unauthorised access to data that could be used to further illegal activities
3. No unauthorised modification of data
91
What is the CDPA (1988) ?
Makes it illegal to copy work that isnt your own without permission of creator or copyright holder, this can refer to text images music videos or software.
92
What does the CDPA act forbid?
Making copies to sell to others
Import/downloading illegally copies
Distributing enough copies to affect the copyright holder.
possessing equipment used to copy
93
2 types of software licenses + definition
How a user can legally use software.
Open source license
proprietary license
94
What does open source mean?
Source code is software code written by programmers
If the sofware is open source, it means users can view/modify source code.
95
Benefits of open source license
+ Since code is editable, it can be tailored to organisations needs
+ Public can work together to modify debug and improve product
+ Unwanted features removed so it can be ran faster.
+ open source software is cheap/free
96
Drawbacks of open source license
- Security risk add malware to program
- Difficult receive support as development is distributed between ppl in diff areas.
- Code may be prone to errors as its not been tested fully
- Requires technical skills to adapt/ maintain source code efficiently
97
What is proprietary license?
Closed source, code is restricted and users are prevented from being able to view/modify source code. You buy right to use software but you dont own it.
98
Benefits of Proprietary licence
Code is well tested and professionally developed, updates are more secure.
Company is accountable if it doesnt perform as listen in the term and conditions upon purchase.
Most developrs will provide some form of help/support
99
Drawbacks of Proprietary licence
Users rely on company to update/fix issues, could be infrequent or gone.
Often not free/expensive
Users can modify/debug/improve code for their own benefit.
100
u think u tha shit?
u ain even the fart (grah)
