NEED TO KNOW MOCKS Flashcards
What are Analogue signals?
Pieces of continuously changing data
Why do Analogue signals need to be converted into digital data?
So computers can read and store sound files
What is Sampling?
The process of converting analogue to digital
What factors affect size and quality of Sound files?
- Bit depth
- Sample rate
- Bit rate
What is Bit depth?
Number of bits available for each sample
What is Sample rate?
How many samples you take in a second
What is lossless compression?
Makes the file temporarily smaller by removing data to store the file
What is a network protocol?
A set of rules for how devices communicate and how data is transmitted across a network
What is a communication protocol?
- Specify how communication between two devices must start and end
- How data must be organised
- What devices must do if it goes missing
What are Mac addresses?
48 or 64 bit binary numbers
—> Binary numbers are converted into hex
What does HTTP stand for?
Hyper text transfer protocol
What is a HTTP used for?
Used by web browsers to access websites and communicate with web servers
What does HTTPS stand for?
HTTP secure
What is a HTTPS used for?
- A more secure version of HTTP
- Encrypts all info sent and received
What does FTP stand for?
File transfer protocol
What is a FTP used for?
Used to access and move files between devices on a computer
What does POP3 stand for?
Post office protocol (version 3)
What is a POP3 used for?
- Used to retrieve emails from a server
- The server holds email until you download it, it’ll then be deleted after
What does IMAP stand for?
Internet message access protocol
What is a IMAP used for?
- Used to retrieve emails from a server
- The server holds email until you delete it
—> WE only download a copy
Who uses IMAP the most?
Web-based email clients
What does SMTP stand for?
Simple mail transfer protocol
What is a SMTP used for?
- Used to send emails
- Used to transfer emails between servers
What is a layer?
A group of protocols which have similar functions
What are the 4 layers called?
- Applications layer
- Transport layer
- Internet layer
- Link layer
What is an Applications layer?
A networking layer which encodes or decodes a message
–> In a form that is understood by the sender and the recipient
Which protocols operate in the Applications layer?
- HTTP/S
- SMTP
- IMAP
- FTP
What is an Transport layer?
A networking layer which determines how a message is transmitted over a network
Which protocols operate in the transport layer?
- TCP
- UDP
What is an Internet layer?
Addresses and packages data, ready for transmission.
—> Then routes the packets across the network
Which protocols operate in the Internet layer?
IP
What is a Link layer?
A networking layer which facilities the transmission of a message across a network
What operates in the link layer?
- NIC
- Operating system drivers
What are the advantages of layers?
- Breaks network communications into manageable pieces
- Self-contained
- Has standards
How is breaking network communications into manageable pieces an advantage in relation with layers?
Helps developers concentrate only on one area of the network without having to worry about the others
How does layers being self contained an advantage?
An individual layer can be changed without it affecting the other layers
How does layers having standards an advantage?
Forces companies to make compatible, universal hardware & software
—> Different brands will work with each other
What is a DNS server?
Stores a list of domain names and a list of corresponding IP addresses where the website is stored
What are the steps taken to display a Webpage?
- Domain name is typed into the address bar of a browser
- A query is sent to the local DNS server for the corresponding IP address of the domain name
- Local DNS server will check if it holds that IP address to that domain name
—> If it does it will pass the IP address to your browser - The browser then connect to the IP address of the server and accesses the web site
What will happen if the local DNS server does not hold the IP address?
Then another query is passed to another DNS server @a higher level until
What is the first stage of the FDE cycle?
The memory address held in the program counter is copied into the MAR
What happens after the memory address held in the program counter is copied into the MAR?
address in the program counter is then incremented by one
What happens after the address in the program counter is then incremented by one?
The processor sends a signal along the address bus to the memory address held in the MAR.
What happens after the processor sends a signal along the address bus to the memory address held in the MAR?
The instruction/data held in that memory address is sent along the data bus to the MDR
What happens after the instruction/data held in that memory address is sent along the data bus to the MDR?
The instruction/data held in the MDR is copied into the CIR
What happens after the instruction/data held in the MDR is copied into the CIR?
- The instruction/data held in the CIR is decoded and then executed. * Results of processing are stored in the ACC
What happens after the instruction/data held in the CIR is decoded and then executed?
The cycle then returns to step one
What is ASCII?
- 7 bits
- 128 character set
What languages would use ASCII?
English
What is Extended ASCII?
- 8 bits
- 256 character set
What languages would use Extended ASCII?
French, Spanish
What is Unicode?
- 16 bits
- Over 65,000 characters
What languages would use Unicode?
Mandarin, Arabic
How is bit rate calculated?
bit depth x sample rate
What are some lossy formats?
- JPEG
- MP3
What are some lossless formats?
- WAV
What are routers used for?
To send data signals across the internet
How do routers work?
Collects knowledge of available routes to transmit data
—> Then determine the most suitable route for sending data
What is a WAP?
Uses a radio transceiver to allow wireless connections to a network
How can WAPs extended the range of a wireless network?
WAP can either receive and transmit traffic to other WAPs
or
It can be connected via a cable to the main network
What factors affect network performance?
- Number of devices on the network
- Bandwidth of the transmission medium
- Type of network
- Network latency
What is bandwidth?
A measure of the amount of data that the medium can transfer over a given period of time
What is network latency?
A measure of how long it takes a message to travel from one device to another across a network
High latency
lots of delays
Low latency
Small amount of delays
What will the latency be like in a hub based network and why?
High latency - hubs broadcast all messages to all devices
What will the latency be like in a switch based network and why?
Low latency - transmit messages only to the intended recipient
Advantages of cloud storage?
- Ability to access files from any location or any device
–> so long as an internet connection exists - Access can be granted to another user so they can remotely access your data
- Reduced need to make backups
- cloud storage services back up the data for you
Disadvantages of cloud storage?
- No guarantee that someone else is not accessing your data
- No guarantee that your data is being backed-up
- Access to data is only possible with an internet connection - no connection means no access to data
Advantages of star network?
- Each node is separately connected - if one fails it will not affect the rest of the network
- Higher performance - message only passed onto intended recipient
Disadvantages of star network?
If switch fails as no node can communicate - whole network fails
Expensive - requires plenty of cable