Sunday, 4 June 2017

Week 10 - Internet Applications for Teaching & Learning

Internet Applications for Teaching & Learning

Asynchrony, in computer programming, refers to the occurrence of events independently of the main program flow and ways to deal with such events. These may be "outside" events such as the arrival of signals, or actions instigated by a program that take place concurrently with program execution, without the program blocking to wait for results. Asynchronous input/output is an example of the latter cause of asynchrony, and lets programs issue commands to storage or network devices that service these requests while the processor continues executing the program. Doing so provides a degree of parallelism.
A common way for dealing with asynchrony in a programming interface is to provide subroutines (methods, functions) that return to their caller an object, sometimes called a future or promise, that represents the ongoing events. Such an object will then typically come with a synchronizing operation that blocks until the operation is completed. Some programming languages, such as Cilk, have special syntax for expressing an asynchronous procedure call.

synchronization refers to one of two distinct but related concepts: synchronization of processes, and synchronization of data. Process synchronization refers to the idea that multiple processes are to join up or handshake at a certain point, in order to reach an agreement or commit to a certain sequence of action. Data synchronization refers to the idea of keeping multiple copies of a dataset in coherence with one another, or to maintain data integrity. Process synchronization primitives are commonly used to implement data synchronization.

Saturday, 3 June 2017

Week 9 - E-mail



Understanding e-mail was originally spelled as electronic-mail. Its the exchange of computer-stored messages by telecommunication. They are usually encoded in ASCII text but, also other types of file can be sent such as graphics, images and sound files as attachments according to their format.


How e-mail works?

  1. The sender composes a message using the email client on their computer.
  2. When the user sends the message, the email text and attachments are uploaded to the SMTP (Simple Mail Transfer Protocol) server as outgoing mail.
  3. All outgoing messages wait in the outgoing mail queue while the SMTP server communicates with the DNS (Domain Name Server–like a phone book for domain names and server IP addresses) to find out where the recipient’s email server is located. If the SMTP server finds the recipient’s email server, it will transfer the message and attachments. If the recipient’s server can’t be found, the sender will get a “Mail Failure” notification in their inbox.
  4. The next time the recipient clicks “Send & Receive,” their email client will download all new messages from their own email server. You’ve got mail!



Week 7 - Web Search Engines


When we talk about search engines, the most popular one and most commonly used is Google followed by Bing and Yahoo. Basically web search engines is a program designed to search documents and information based on the keyword entered in World Wide Web (also known as www)
Search engines can be installed anywhere on your smartphone, tablet, computer, laptop and many more where you can access using the internet.

How Search Engines Work?

I used to understand when I enter any keywords i wish to find, the google will find it for me. But as learn more, actually I'm searching the index google instead of google itself. They are called spiders that functioning to fetch source from few webpages and link to another webpages and all the information grabbed by the spiders will be shown on its search lists. Video below will explain more about it




















From the page >click< Once a page has been crawled, the data contained within the page is processed and indexed. Often, this can involve the steps below.
Strip out stop words.
Record the remaining words in the page and the frequency they occur.
Record links to other pages.
Record information about images or other embedded media.

The data collected above is used to rank the page and is the primary method a search engine uses to determine if a page should be shown and in what order.

Finally, once the data is processed it is broken up into one or more files, moved to different computers, or loaded into memory where it can be accessed when a search is performed.

Basically, the search engines we use work as searcher and grab all the information or findings based on the keyword we entered but, the engines were controlled by the spider that fetches all information and gathers.


Monday, 29 May 2017

WEEK 6 - Network Protocols and Standards



The topic that we have learnt today is network protocols and standard.. The topic gives me loads of information about the protocols of using internet.
A protocol is a particular set of rules for having a conversation between two computers to convey a specific set of information. A standard (and in the networking arena, many protocols are standards) is a document that specifies something that has the overwhelming support and agreement of the standards making body.

Standard

  1. An example of standards would be 802 standards for ethernet3GPP for mobile communication etc.
One of them, 802.3u, lays down the specifications related to FastEthernet. If anyone were to design a hardware or software related to FastEthernet, they would have to follow those specifications and that new design would work with all the pre-existing, as well as future software's | hardware's implementations of FastEthernet


Protocol

  1. An example of protocol would be TCP/IP,DHCP,ICMP,GTP,DIAMETER,RADIUS etc.
The specifics of the above would detail the addressing format, number of bits used, methods to decide grouping, size of data chunks and more

WEEK 5 - Connecting a Network : Wireless Technology

Basically wireless is a term used to describe telecommunication which using electromagnetic waves rather than using wire to transmit signals. As the table above showed pros and cons of wired and wireless technology. Wireless technology is generally used for mobile IT equipment. It encompasses cellular telephones, tabs,personal digital assistants (PDA's), wireless networking and many more.

There are so many uses of wireless technology in our daily life as students, employers, employee, teachers, scientists and others. For example, radio waves are used to transmit television and radio programs, microwaves used to transmit mobile phone calls, to connect network computers togethers. On other hand, radio stations that has similar transmission frequencies can interfere each other's signals. As you can see, wireless communications can be available at all time and almost everywhere. After all, this wireless technology is so convenient that no wires need to be run through building, over ground or underground. They are PORTABLE!

As we know there are lots type of networks such as 
  • LAN - Local Area Network
  • WAN - Wide Area Network
  • WLAN - Wireless Local Area Network
  • MAN - Metropolitan Area Network
  • SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network
  • CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
  • PAN - Personal Area Network
Everyday, our technology is evolving and developing from one to another. We are getting close to world at the tip of finger where everything can be controlled with one single click. However, still we need to use this technology for better use rather than depending on it.




Saturday, 27 May 2017

WEEK 4 - Connecting a Network : Cabling and Hardware



This week I will explain more about networking software, wired network-types of cables and networking and their functions.



wired network - types of cables


coaxial cable connector uses Bayonet-Neil-Concelman (BNC) connector.

  1. fiber optic cable able to transmit signals over longer distances.
  2. it transmit light and eliminate the interference.
  3. for example, unifi. 
  4. fiber optic uses ST & SC connector.



SHIELDED TWISTED PAIR (STP)
  1. Two individual wires wrap in a foil shielding.
  2. Shielding provides a more reliable data communication
  3. Suitable for environment with electrical interference
  4. Disadvantage: Extra shielding causes more bulky

UNSHIELDED TWISTED PAIR (UTP)
  1. Has 4 pairs of wires inside the jacket
  2. Each pair is twisted with a different number of twists per inch- to eliminate interference from adjacent pairs and other electrical devices
  3. Disadvantage: may be susceptible to radio and electrical frequency interference.
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NETWORK HARDWARE

Networking hardware includes all computers, peripherals, interface cards, and other equipment needed to perform data-processing and communication within network.

File Server : large amount of RAM and storage space
                      : a fast network interface card

Workstation : configured with appropriate cables, network interface card and networking software
                         : do not necessarily storage capability, files saved on file server

- Network Interface Card : physical connection between network and workstation
                                             : 3 most common network interface → Ethernet card
                                                                                                       → LocalTalk connector
                                                                                                       →Token Ring card

- Concentrator/Hubs : central connection point
                                     lots of extra network trafic, network less efficient
                                     : for all traffic network

- Switch : can connect ethernet, toking ring and fiber channel
               : for one traffic channel

- Repeater : to boost signal
                   : can be separate device or incorporate into concentrator

- Bridges : connect multiple network segments
                 : connect different types of cabling or topology

- Routers : used to link different networks
                 : translates information from one network to another = superintelligent bridge
                 : direct signal traffic efficiently
                 : route messages between topology and cables

Network Gateway 


  • Internetworking system → joining together two networks that use different base protocols.
  • Can be implemented completely in softwarehardware or combination of both.

Friday, 26 May 2017

WEEK 3 - Computer Networking

Understanding what is computer and networking, literally computer is all those hardware including CPU, monitor, mouse and cables connected to each other to operate the computer and networking can be understood as link that connected to interact with other people to exchange information and develop contacts, especially to further one's career.

Here's a short video to understand how computer networks worked and connected


There are lots of type of networks 
  • CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
  • PAN - Personal Area Network
but basically we are exposed to LAN, WLAN and MAN compared to others. They are functioning to share internet connection, application software, printers and other resources. However, they also facilitate VoIP (Voice over IP), e-mail, video conference, messaging and other communication applications. These network also work collaboratively, especially in sharing a company database or using collaboration tools to create or review documents, exchanging files among network users over the internet as long as they connected to the same network and it also connect the computers and the entertainment devices such as TV, gaming consoles and many more that located within the home or area.

These are the components of network that are vital to make the computer networking works



1. Host/End nodes


Refers to the data source and destination
Examples:
Personal Computers
Workstations
Terminals
Automatic Teller Machine


2. Transmission media


For transmitting data and control signals
Sending signal through specific media
It can be bounded or unbounded media
Bounded media:
Coaxial wire
Twisted pair wire
Fiber optic cable
Unbounded media:
Radio signals
Satellite transmission
Infrared transmission


3. Network Electronic Devices


Control data from source to destination
Provide interface between different media transmitter or different protocol
To connect multiple network together
Examples:
Bridges
Routers
Multiplexers
Switches
Hubs
Gateways
Front End Processors


4. Software/Applications

Involves technique and protocols
The protocol determines the rules and procedure to send, terminate,interpret and present data and control mistakes.
To control data transmission


5. Network Architecture Standards & Protocols
The blueprint of standards that define:
How a device in a network typically connect
How a device can communicate
To enable devices made from different companies to communicate with each other.
Example:
TCP/IP
Ethernet (802.3)
Wi-Fi (802.11)
Wimax