Paper 2 Flashcards
(81 cards)
1
Q
Four functions of an operating system:
A
- Processor management
- Memory management
- Storage management
- Network management
2
Q
Low level language:
A
- Code is not translated using a compiler
- Code can directly manipulate computer registers
3
Q
It is a program translator
Assembler:
A
Translates assembly language into machine code.
4
Q
How does an interpreter work:
A
- Interpreters don’t produce machine code, so the program needs to be translated each time it’s executed.
- They call machine code subroutines withhin their own code to carry out their commands
- Translates a line at a time, which it then executes
- If a runtime error is found, the interpreter stops
5
Q
Why do computers have more RAM than cache memory?
A
- RAM is cheaper
- Cache memory is not enough to store both data and programs
6
Q
Two advantages of using cloud storage, rather than local storage:
A
- Cloud storage is automatically backed up by the host
- Allows user to access their data from more devices
7
Q
Many new computers use solid-state storage for secondary storage rather than magnetic storage.
Explain why solid-state storage is not fitted to every new computer.
A
- SSD’s are expensive
- They have a lower capacity than magnetic hard drives
8
Q
Sample resolution:
A
Number of bits per sample
9
Q
Differences between a Local Area Network (LAN) and a Wide Area Network (WAN):
A
- LAN’s and WAN’s use different protocols
- WAN’s are slower than LAN’s
- WAN’s have a larger number of users
10
Q
Give three advantages of using a wireless network instead of a wired network:
A
- Users can move around whilst using their device
- Able to add users/devices to the network
- No need to install cabling
- BUT, BANDWITH IS LOWER THAN WIRED NETWORKS
11
Q
System software:
A
Controls computer hardware
12
Q
Application software:
A
Is for ending user tasks
e.g social media application or gaming software
13
Q
Network protocols:
A
A set of rules for how devices communicate and how data is transmitted. Covers how communication between two devices should start and end.
14
Q
Security measures:
A
- Two-factor authentification, asks for a second form of identification
- Biometrics- biometrics is unique to the individual, prevents hackers
15
Q
Why might data be compressed?
A
- Reduces file size
- Uses less memory
16
Q
Relational database
A
A database with multiple tables that are linked together.
ADVANTAGES- reduces data inconstistency
- Saves storage space
17
Q
Foreign key:
A
A field that references the primary key in a different table.
18
Q
What are the equations of file size?
A
- File size (in bits)- image size * colour depth
- File size (in bits)- Sample rate (Hz) * sample resolution * length (s)
19
Q
Network protocol 1- the APPLICATION LAYER:
A
Sends web pages, using an encrypted connection(e.g. http/s).
20
Q
Network protocols 2- the TRANSPORT LAYER:
A
Sets up communication between two devices, splits data into packets, checks if packets are correctly sent and delivered (e.g. TCP).
21
Q
Network protocols 3- the INTERNET LAYER:
A
Adds IP adress to packets, directing them between devices. Used by routers (e.g. IP)
22
Q
Network protocols 4- the LINK LAYER:
A
Passes data over the physical network. Responsible for how data is sent as electrical signals over cables (e.g. wifi)
23
Q
Increase sampling rate- effects:
A
- The file size would increase
- The more samples means that the sound would be recoded at a higher quality
24
Q
RAM
A
- Is used for main memory
- Is used for volatile memory
- Temporary storage of instructions and data
- Holds information being executed by the processor
- Much faster than the hard disk
25
Factors that affect CPU performance- clock **speed:**
**Clock speed**:
* The **more pulses** per s**econd**, the more **fetch-execute cycles**
* **Higher** clock speed- **more instructions** can start per **second**
26
Factors that affect CPU performance- the **number of processor cores**:
**Number of processor cores**:
* **Different** processor **cores** deal with **different** types of **instructions**
* Each processor **core can fetch it's own instruction**- increases the speed at which instructions can be executed.
27
Factors that affect CPU performance- **Cache size**:
**Cache size:**
* **Instructions** take **less time** to transfer to the **processor from cache**
* Because cache is **held closer** to the **processor**
28
Computer network:
* **Two** or more **computers**
* **Connected** together
29
How does two-factor authentification work?
* Asks for a **second** piece of **identification**
* Such as something you know
30
Data privacy concerns
(wireless network):
* **Malware infiltration**- Wifi is more **exposed** to an attack because it is **visible**
31
**ASCII**
7 bits per character. Room for 2^7= **128 characters**.
**Disadvantages**: Does not have enough characters for many languages.
32
Unicode
Represents **thousands** of characters.
33
Colour depth
Number of **bits** per **pixel**
34
No. of colours
No. of colours= 2^colour depth
35
Utility software:
Supports running of the computer system
36
Operating software:
**Manages hardware and other programs**
E.g.:
* Processors
* Memory
* Input/output
* Applications
* Security
37
Machine code:
**The language the computer can directly execute**
* Easier to **optimise**
* However, it is very **specific** to every CPU
* Binary representation
* Faster to execute
38
High level language:
* Like written english
* More **readable**
* **Portable**- can run on many CPUs
* However, it is **slower** to execute
39
Compilers:
**Translate the high level language into machine code**
* **Fast** to execute
* However, **errors** are only shown at the **end**
40
Star topology:
Main **computers** connected to a **central device**.
* Easy to add new devices
* Decent level of security
* However, you are reliant on central node
41
Bus topology:
**Computers connected by a central wire.**
* Simple and cheap to set up
* Not dependant on a central server
* Low performing- many collisions
42
Fetch- execute cycle:
1. Fetch- Next instruction is loaded from main memory
2. Decode- Instruction is interpreted by CU.
3. Instruction is carried out
43
State **two issues** with only using **usernames** and **passwords** in an **authentication**
system.
* Weak passwords are easily cracked
* Usernames/passwords may appear in a data leak
44
Why is run length encoding not a suitable method sometimes?
* The data do **not** have a **high frequency** of **consecutive repeating characters**
* The data will take up **more storage** than the **original data**
45
Penetration testing:
* The process of **attempting** to **gain access** to a **computer system**
* Without the **knowledge** of **usernames**
46
Aim of a **white-box penetration test:**
To **stimulate an attack** from an **insider** that has the **knowledge of credentials** to the **targeted** **system**.
47
Primary storage:
* With the exception of ROM all **are volatile**
* ROM is considered **read only**
* Relatively **small capacity** compared to **secondary storage**
* Very **fast access time** compared to **secondary storage**
48
ALU:
**Responsible for carrying out:**
* Arithmetic calculations
* Malking logical decisions
49
CU:
* Sends **signals** to control how **data** **moves** around the **CPU**
50
Cache:
* Provides **fast access** to **frequently** used **data** and **instructions**
51
Clock:
* The **electronic unit** that **synchronises** related **components** by generating **pulses** at a **constant rate.**
52
Registers:
* **Tiny, superfast** pieces of **onboard memory** inside the **CPU**
* Each has a very **specific purpose**
53
Buses:
* **Collection of wires** through which **data** and **instructions** are **transmitted** from one **component** to another
54
Definition of computer:
* An electronic device which takes in an input, processes data and delivers an output
55
Clock speed:
* Measured in Hz
* Number of cycles per second
* Modern processors operate at billions of cycles per second
* 3.2 billion instructions can be fetched per second (3.2 Ghz)
56
Embedded system:
* **A computer system with a dedicated function within a larger mechanical system**
**TYPICAL PROPERTIES:**
1. Low power consumption
2. Small size
3. Rugged operating ranges
4. Low cost per unit
**EXAMPLES:**
* Traffic lights
* Domestic appliances (washing machines)
* Hospital equipment
57
Secondary storage:
* All are **non-volatile**
* Much **larger storage capacity** compared to primary storage
* Very **slow access times** compared to primary storage
58
ROM:
* **Small** piece of read only memory located on the **motherboard**
* **Non-volatile**
* Contains **very first instructions** for the **computer**
59
Why is secondary storage needed?
**Secondary storage is needed because ROM is read only and RAM is volatile**
**Secondary storage is needed for:**
* Storage for **programs** and **data** wwhen the computer is **turned off**
* **Backup** of data files
* **Archive** of data files
60
Cloud storage:
**Remote servers that store data that can be accessed over the internet**
* Typically uses magnetic hard drives
* Use of SSD's is increasingly popular
61
Advantages of cloud storage:
* Access your files anywhere, anytime or from any device
* Automatic backup is possible
* Files no longer take up any space on your own device
62
Disadvantages of cloud storage:
* Can be expensive, monthly or yearly subscriptions
* No access to files without an internet connection
63
Advantages of networking:
* Users can **share files**
* **Communication** with other **people**
* Users can **access** their **files** from **any computer** on the **network**
64
PAN:
**PAN is any commputer which uses data transmission amongst very localised devices:**
* Cell phone
* Tablet
* Most **common communication technology** used in PAN is **bluetooth**
* Very short range, 10 metres
65
Disadvantages of networking:
* Increased **security risks to data**
* The **computer** may **run more slowly** if there is a **lot of data** travelling on the **network**
66
What is a protocol?
A protcol is a set of rules that allow two devices to communicate
67
Ethernet:
**Family** of **related protocols,** providing the **basics** of **communication** over a **LAN.**
68
Wifi:
* **Family of related protocols** providing the **basics** of **wireless communication**
69
TCP:
* Provides an **error free transmission** between **two routers**
70
UDP:
* Part of the **internet protocol suite,** used by **programs** running on **different computers** on a **network**
* Used to **send short messages** called **datagrams**
71
IP:
* **Routes packets** accross a **WAN**
* Along with **TCP** it makes up the **TCP/IP stack.**
72
**HTTP:**
* A **client-server** method of **requesting** and **delivering HTML webpages**
73
Protocols for handling webpage requests- **HTTPS:**
* **Encryption** and **authentication** for **requesting** and **delivering** **HTML** web pages
* Used when **sensetive information** needs to be **transferred** e.g. **passwords** and bank account details
74
**FTP:**
* Used for **sending files** between **computers,** usually on a **WAN**
75
Email protocols- **SMTP:**
* Sends emails to an email server
76
Email protocols- **IMAP:**
* Used by **mail clients** to **manage remote mail boxes**
77
Social engineering meaning:
* The art of manipulating people, so they give up confidential information
78
Maliciuos code:
* Any **software** designed with the **intent** to **cause damage, dsiruption or inconveience**
* E.g. **virus, trojan, spyware**
79
**Weak and default passwords:**
* People not changing their password, or using easy to guess/ short passwords
80
**Unpatched/ outdated software:**
* Out of date **operating system** that can have **flaws** which get **exploited**
81
Misconfigured access rights:
