Science & Technology in Action

8th Edition

Understanding the Cloud

EMC

In this lesson we look at the radio spectrum and the communication services that depend on it. We also discuss the role of ComReg in managing the use of the spectrum and the need for such management. An extra Poster Sheet on ComReg is included in the folder.
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Contains the full lesson along with a supporting toolkit, including teachers’ notes.

Lesson excerpt

Cloud computing is very much in the news these days. We keep hearing about it but may not be sure what it means. You may have used your computer to compose a document or to construct a presentation about a project you are doing. To carry out these tasks you needed to access a word processor or presentation application. Word and PowerPoint are two very well-known examples of such applications. These software packages are probably resident on your hard disk and you accessed them by clicking on the appropriate icon. On the other hand, when you use your browser to connect to a website, that website is resident on a server somewhere on the internet and you actually don’t know where. If you think about this, you may come up with a question – why can’t I access a word processor or presentation application on the internet? The answer is that you can, and this is called cloud computing. In this lesson we look at this recent trend and examine some of its features.

What does cloud mean?
The internet is a complex global network with many routers and transmission links. Since the early days of telecommunications it has been standard practice for network engineers not to show all this detail, but to draw the network in the shape of a cloud with the users connected to it. A computer that is accessing a server is called a client.

How is connection made?
Every machine on the internet has a unique identifying number, called an IP Address (Internet Protocol Address). A protocol is a set of rules and IP is the protocol that computers on the internet use to communicate across the internet. You are probably familiar with the format of an IP address - four groups of decimal numbers separated by a decimal point.

True or False?

  1. The provision of extra equipment to ensure service at all times is called ‘redundancy’. true
  2. IPv4 offers more addresses than IPv6. false
  3. A DNS server converts a domain name to an IP Address. true
  4. Humans can easily understand machine readable language. false
  5. There are four binary digits. false
  6. The unit of storage capacity is the ‘bit’. true
  7. Routers decide the best path to connect clients and servers. true
  8. A URL is a binary representation of an IP address. false
  9. EMC in Cork manufactures computer storage systems. true
  10. There are twelve bits in a byte. false

Glossary of terms

Application
binary numbers
big data
big data analytics
bit
byte
chips
data centres
database
domain name server (DNS)
gigabyte
hard disk
internet
IP address
laser diode
lights-out