C.3 Distributed Approaches to the Web Flashcards
C.3.1
Define mobile computing
Mobile computing is a technology that enables data, voice, and video to be transmitted wirelessly from a computer or other wireless enabled device without the need for a fixed physical connection.
C.3.1
Define ubiquitous computing
The idea of ubiquitous computing is having a computer with you at all times. Ubiquitous computing enhances how we use computers by making network-connected computer devices available throughout our physical environment, and the same time making them invisible or at least unobtrusive. The general idea is to embed everyday objects with computational capabilities, such as smart fridges, self driving vehicles, etc.
GENERALLY, THE IDEA IS: being able to use computer wherever you are.
C.3.1
Define peer-2-peer network
A P2P network is one in which two or more PCs share resources and access to devices such as printers without requiring a separate server computer or server software.
C.3.1
Define grid computing
Grid computing is the utilisation of multiple computers, often geographically distributed but connected by networks to work together to accomplish joint tasks and solve problems. It is typically run on a “data grid,” a set of computers that directly interact with each other to coordinate jobs. Grid computing works by running specialised software on every computer that participates in the data grid. The software assigns subtasks to each computer so they can work simultaneously on their respective subtasks. After the completion of subtasks, the outputs are gathered and aggregated to complete a larger-scale task.
C.3.2
What are the pros/cons of mobile computing?
Advantages
Efficient and seamless connection
Connection is more portable as there is no need for a physical link.
Cloud Computing- This program allows you to save data on an online server and access them from any computer with an internet connection.
Disadvantages
Data transmission is limited by transmission bandwidth. (transmission bandwidth is the maximum amount of data transmitted over an internet connection in a given amount of time)
Stability of the network may fluctuate
Obstacle of battery consumption
C.3.2
What are the pros/cons of ubiquitous computing?
Advantages
More precisely targetted advertising
More efficient devices
Faster reaction times in healthcare services
Disadvantages
Privacy and security is a challenge. Making sure all the network-connected devices are cyber safe is hard.
C.3.2
What are the pros/cons of P2P network?
Advantages
No need for expensive servers
No need for specialist staff such as network technicians
Easier to set up than a client to server network
If one computer fails it will not disrupt any other part of the network. It just means that those files aren’t available to other users at that time.
Because there is no central point of control, P2P networks can be more resilient to attacks such as denial of service (DoS) attacks, as there is no single target.
Disadvantages
However, P2P networks can also be vulnerable to attacks that exploit weaknesses in the protocol or in individual node
Because each computer might be being accessed by others it can slow down the performance for the user.
Files and folders cannot be centrally backed up.
Difficult to locate files because they are not stored in a centralised area.
C.3.2
What are the pros/cons of grid computing?
Advantages
It can use existing hardware
Scalable
Inexpensive
Can easily associate with other organisations (Grid computing is especially useful when different subject matter experts need to collaborate on a project but do not necessarily have the means to immediately share data and computing resources in a single site.)
Disadvantages
A big learning curve to get started
It is a relatively new technology, so the standards and software is still evolving.
C.3.3
Distinguish between interoperability and open standards.
Interoperability is the ability for two or more systems to exchange and use information.
A standard is a set of specifications for hardware or software, agreed upon by academic and industry contributors.
Open standards are standards that are made available to the general public and are developed and maintained by various organisations.
C.3.3
List 5 examples of open standards
There are many open standards to keep the internet functioning:
HTML, CSS
Open standards for documents:
JSON, XML, CSV
C.3.5
Benefits of a decentralised web
If a server fails, it will not disrupt major parts of the network.
Distributed Systems provide unmatched scalability as we can easily add more nodes in a particular network.
Distributed systems handle system failures better than centralised networks
In today’s world, time is an important constraint for business personnel and users alike. Distributed Systems provide a low latency rate. For example, consider a user who uses the internet and loads a website. The system makes sure that the node located closer to the user is used to perform the loading task in order to save time.
Distributed systems are more efficient as involves multiple computers.
C.3.5
Disadvantages of a decentralised web
It poses security risks as there are more entry points for viruses to enter the network. There are more devices, servers and databases that need to be secure.
Setting up a decentralised system is more expensive as there are more authorities.
A distributed system is quite complex which makes it difficult and expensive for the network to maintain and troubleshoot.
C.3.5
In the future, will there be more centralisation or decentralisation of the web?
The web started out as a decentralized system but as it grew, our online presence has become more and more centralized on corporate platforms like Google and Amazon. The hope of web 3.0 is that there will be new web protocols and infrastructure that should allow developers to build decentralised apps. However, in reality, the majority of the web is still very much centralised.
C.3.6
What is lossless compression
Lossless compression removes data without degrading the quality of the file. For example, a type of lossless compression in images is run-length encoding. It takes all the runs of data that are the same, and replaces the redundant / repeated data with a single data value and the number of times that data value is repeated in a run.
C.3.6
What is lossy compression?
Lossy compression is the process of removing unimportant data in a file to reduce its size. Lossy compression typically reduces the file size significantly more than lossless compression. For example, lossy compressed audio files usually have sounds outside the human hearing range removed. Lossy compression may also reduce the bit depth of audio files, it may also reduce the colour depth of images.
