Category: Information System Design and Development

N5 – Technical implementation (storage)

Some of you were concerned that I had missed something that was on your revision sheets, so I thought I might revisit it here. In the previous post I had decided to reorganise this section, which wasn’t reflected in the CAS.

Description and exemplification of the appropriate type of storage required for a specific information system including:

Type of device

It is important to pair the correct type of device with a specific information system. Systems that require a lot of storage like video or image libraries often prioritise this over very fast access to a hard drive is used. While systems that require fast access like video editing will make use of solid state devices.

Capacity

The rule of thumb with capacity is bigger is better, however, this can come at a substantial cost. It is therefore important to understand the needs of the IS, a server will require subtancialy more capacity than a presentation for example.

Interface type

Portable Information Systems will require USB ports to connect to. Some IS devices may make use of wirelesss connections. The computer must have the same interface as the IS device.

N5 – Coding

Description and identification of coding to create and modify information systems including JavaScript mouse events.

Javascript is used in HTML documents to add interactivity. The HTML file below has a number of interactive elements to it. Use notepad++ to investigate it further.

<!DOCTYPE html>
<html>
<head>
<title> Teacher Example  </title>
<!--     
The <script> in the <head> tag allows the functions to be called from 
anywhere in the document
-->
<script>

<!-- Changes Style on Mouse Over -->
function mouseOver() {
document.getElementById("demo").style.color = "red";
}

<!-- Changes Style back after Mouse Over -->
function mouseOut() {
document.getElementById("demo").style.color = "black";
}
<!-- Asks for and displays a name -->
function myFunction() {
<!-- Asks the user to enter their name -->
    var person = prompt("Please enter your name", "Harry Potter");
	<!-- Displays the persons name in ID demo3 -->
    if (person != null) {
        document.getElementById("demo3").innerHTML =
        "Hello " + person + "! How are you today?";
    }
}
</script>

</head>

<body>
<!-- Display a heading that can be changed later -->
<h1 id="demo" onmouseover="mouseOver()" onmouseout="mouseOut()">Welcome</h1>

<!-- Displays a button that when pressed will display the date in the first Heading-->
<p>
<button type="button"
onclick="document.getElementById('demo').innerHTML = Date()">
Click me to display Date and Time.</button>

<!-- Uses Javascript to display the message "Your Text Here" -->
<p>
<script>
document.write("Your Text Here");
</script>

<!-- The text RESULT is not displayed as it is replaced by 
     the results of the calculation below it-->
<h1 id="demo2">RESULT</h1>
<script>
var price1 = 5;
var price2 = 6;
var total = price1 + price2;
document.getElementById("demo2").innerHTML =
"The total is: " + total;
</script>

<!-- This button calls the function myFunction from above -->
<p>Click the button to demonstrate the prompt box.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo3"></p>

</body>
</html>

Description, exemplification and implementation of coding to create and modify information system including the use of HTML with the tags for:
o Document
o Links
o Graphics

The documents below show a HTML document with the basic html document tags and a document showing the html tags for links and images 

<!DOCTYPE html>
<html>
<head>
<title> </title>
</head>
<body>

</body>
</html>

<!DOCTYPE html>
<html>
<head>
<title> Page1 </title>
</head>
<body>
<h1>Example of a heading of type 1</h1>

<h2>And this is heading 2</h2>

<!-- The anchor tag <a> is used to link a html document to another document. 
     The href attribute gives the name of the destination of the link. -->
<p>Here is a paragraph of text,
which includes a link to <a href="page2.html">page 2</a></p>

<p>
<!-- The image tag <img> is used to display an image.
     The src attribute is the name of the image -->
<image src="logo.png">

</body>
</html>

Technical Implementation (software requirements)

operating system platform required  
An Operating system is required to allow all parts of a computer system to communicate with each other and with the user.
Describe the purpose of an operating system including:  
controlling peripherals  
The OS controls the Input and Output to attached peripherals using device drivers.
running software  
The OS schedules software access to the processor, this allows several pieces of software to appear to run at the same time. Example Word-processing while listening to music.
HCI  
The Human Computer Interface is how the user and the operating system communicate with each other. The two main types of HCI are command line where the user types command and graphical where the user runs applications and command using icons and a pointing device.
Understand the features of web browsers including:  
OS support  
Web browsers are often available for different operating systems. This allows the for the same browser experience on different platforms.
privacy modes  
Most modern browsers have a privacy mode that clears browsing history and downloads from the computer at the end of the session. This is useful if you are trying to buy a gift and want it not to show up in your browser history.
Ad filtering  
Browsers have the ability to block adverts, this can either be in the form of a pop up blocker or an extension that removes adverts from the pages. This might cause problems in the future as websites are ran by companies who need to make a profit to pay for the website.
page zooming  
Some people require fonts etc. to be a little bit bigger to make them easier to read. Web pages can therefore be zoomed to increase the size of hard to read content.
Description and exemplification of the appropriate type of software required for a specific information system including:  
type of application  
Word processor, spreadsheet, database, multimedia, presentation, web page authoring software, games.
operating system  
Before buying or using an application you need to make sure that it is compatible with the operating system used on the computer.

N5 – Technical implementation (networking/ connectivity)

stand-alone or networked
A stand-alone computer is not connected to any other computer.

A network computer is connected to other computers via a network, this can be either wireless or wired
LAN/internet
Local Area Network – This a network of computer in a small geographical area, such as a building.

Internet – This is a worldwide network of computer networks.
Description and comparison of the following transmission media in relation to data speeds and ease of use:
wired
A wired network connect is fast connection, which makes use of copper cables to connect to other network devices. This type of network is used for LANs as it has a short range.
optical
Optical networks use fibre optic cables to connect devices together. The data is transmitted as a series of light pulses. Different colours can be sent of the same cable allowing for more than one piece of data to be transmitted at once. Optical networks have the largest range and are often used in undersea cables.
wireless
Wireless networks allow network data to be transmitted without a dedicated wire. The most common are Wi-Fi and Bluetooth. Wi-Fi has the largest range and fasted speed but Bluetooth is the most energy efficient.
Description and exemplification of hardware required for network connectivity including:
Network Interface Card
A NIC is used to connect a device to the network, these can be wired or wireless. The NIC makes sure that the device’s data is

Wireless NICs are often in the form of a USB dongle that can be plugged into any computer or device.
Router
A network router is used to connect one network to another. We use routers to connect our house networks to the Internet. Home routers often have Wi-Fi built in as well as a network switch.
Hub
A network hub is used to connect computers together in a network. Hubs are used in star networks where all the clients share the same bandwidth.
Switch
A network switch is used to connect computers together in a network. Switches have high bandwidth and each device has a direct switched connection to each other.
Description and exemplification of the appropriate type of network connection required for a specific information system including:
Hardware
To connect two or more computers in the network you would need.

·         A NIC for each computer

·         A network hub or switch

·         Cables for a wired network.
transmission media
Transmission media is the connection between two network devices.

·         Wi-Fi & Bluetooth – Wireless radio signals

·         Optical – Fibre optical cables

·         Twisted Pair – Copper cables that are twisted around each and plug into NICs

N5 – Technical implementation (storage)

Comparison of local versus cloud storage  
Since the contents of RAM is lost when power is disconnected it needs to be stored, so it can be used latter.

Local storage is used to store the information on the computer, such as a hard drive or flash drive.

Cloud storage, stores the information on the Internet where it can downloaded and used later.
Comparison of built-in versus portable storage  
Built in storage is fixed inside the computer and cannot be removed. This is normally a Hard Drive or Solid State Drive.

Portable storage can be moved between computer systems, to allow data to be transferred. E.g. Optical Disc, portable hard drive or flash drive.
Comparison of different interface types and their data transfer speeds including:  
Firewire  
This is a wired interface that can connect a device to the computer at speeds of up to 800Mbps. This is often used for portable hard drives or digital video cameras. Devices can be daisy chained together so that up to 63 peripherals can be connected.
USB  
Universal Serial Bus is a wired interface that can connect a device to a computer at speeds of up to 7.2Gbps. A USB hub is used to connect many devices together up to 127 devices can be connected together. Many different devices can be connected via USB including Keyboards, flash drives and mobile phones.
Bandwidth  
Bandwidth is the amount the data that can transferred in a fixed amount of time. This is often expressed in bits per second (bps). A high bandwidth connection is often referred to as broadband.
Description of different types of storage devices and their media in terms of functionality, speed and capacity (in appropriate units) including:  
magnetic  
Hard disk drives are an example of magnetic storage. These random access devices are used to store large amounts of data, 10TB disks are available. Although they can be portable, they are quite fragile and need to be handled with care.
optical  
CDs, DVDs & Blu-Ray are example of optical storage. The information is stored on a disc and read using a laser. The discs are portable but the drives themselves are very sensitive to vibration and can only be used in fixed location. Optical discs can store up to 50GB on one disc.
rewritable, read-only  
Optical discs are available in many configuration and are often suffixed with;

-ROM – Can only be read and not written to.

-R – Is a recordable disc which can be written to once and read many times

-RW – ReWritable discs can be written to many times
solid state  
A solid-state drives have the fastest access and transfer times of any storage device. SSDs are portable in the form of flash drives and are very robust. They are however quite expensive and cannot currently store as much as a hard drive.
Description and exemplification of the appropriate type of storage required for a specific information system including: type of device, capacity & interface type  
Server Based
Servers require fast, cheap storage with a large capacity. As a result, Hard Disk Drives are used. This allows the most amount of storage with the cheapest cost.
Backup
Optical Discs are often used to backup information. As these discs, can be stored securely in a different place from the computer.
On the move
Solid State Flash Drives are very portable with a large storage capacity. These are robust and not susceptible to damage from vibration.

N5 – Technical Implementation (hardware requirements)

Description and exemplification of the appropriate type of hardware required for a specific information system including:
input and output devices
A device which is used to enter information in to a computer system is called a input device. E.g. Keyboard, microphone, mouse, etc.

A device which the processor can send data to or display data on is an output device. E.g. Speakers, monitor, printer, projector, etc.

Some devices are both input and output devices. Touch screen, rumble controller.
processor type and speed (Hz)
Some processors are better suited to certain tasks. So a processor that uses less power might be better suited for a mobile phone or laptop.

In general, the faster the processor the more power it requires, so mobile processors often run a slow speed to desktop processors.
memory (RAM, ROM)
The more memory a computer has the more things it can do at the same time.

More memory requires more power, so mobile computers often have less RAM and ROM than desktop computers.
memory capacity (RAM)
Computer memory is measure in GB. Often computers don’t have the maximum amount of memory installed, this is often due to the costs involved.

N5 – Graphic Formats (Revision)

Graphic Formats

JPEG (.jpg) Lossy compression

  • 24 bit colour.
  • Allows the user to select an appropriate level of compression.
  • JPEG is a good compression format for high-quality images and images where quality is unimportant (e.g. thumbnails).

PNG (.png) Lossless compression

  • Intended to improve upon GIF format.
  • 24 bit colour.
  • Allows user to set alpha level for improved transparency.

GIF (.gif) Lossless compression • Restricted to 8 bit colour.

  • Several images can be stored in one GIF file, allowing for animation.
  • Allows a specific colour in an image to be made transparent.
  • GIF is a good compression format for images with areas of flat colour, images that have few colours, animated images or images that require transparency.

Graphic file size calculations

To calculate the file size (in bits) of a bitmap graphic file the basic formula is:

number of pixels in image x bit depth

  • Bit depth or colour depth is the number of bits that were used to store the colour of each pixel.
    • 8 bit – 256 colours
    • 16 bit – 65536 colours (High Colour)
    • 24 bit – 16777216 colours (True Colour)
  • DPI (dots per inch) the number of pixels in a physical inch of paper.

Example 1
Calculate the file size of a 400 x 400 pixel graphic with a colour depth of 24.

400 x 400 = 160000 pixels in the image
160000 x 24 = 3840000 bits
3840000 / 8 = 480000 bytes
480000 / 1024 = 468.75 KB

Example 2
Calculate the file size of a 300 x 200 graphic with 256 colours.
256 colours means a colour depth of 8 (because 2^8 = 256)

300 x 200 = 60000 pixels in the image
60000 x 8 = 480000 bits
480000 / 8 = 60000 bytes
60000 / 1024 = 58.6 KB

Example 3
Calculate the file size of a 6’ x 5’ image, scanned at 200dpi, with 16 bit colour.

6 x 5 x 200 x 200 = 1200000 pixels in image
1200000 x 16 = 19200000 bits
19200000 / 8 = 2400000 bytes
2400000 / 1024 = 2343.75 KB
2343.75 / 1024 = 2.3 MB

BGE – Media Type (Audio)

soundIn class today we used Audacity to explore how sound is stored inside a computer.

The sound wave energy is converted into electricity by the microphone, which is in turn converted to binary by the sound card.

We used Audacity to capture our voices then apply digital effects to them to change the sound.

You can use specialised websites and software such as http://sfbgames.com/chiptone , to create purely digital noises. These can then be saved and used inside other programs such as games.

Higher – Technical Implementation Hardware Requirements – Revision

Comparison of

  • input devices
    • Digital Camera
      • Resolution – Measured in mega pixels, typically the larger the better.
      • Optical Zoom – How close you can make the image appear without losing any quality.
    • Touch Screen
      • Resistive – Single touch
      • Capacitive – Multi touch
  • output devices
    • Printers
      • Resolution – Measured in DPI (dots per inch)
      • Speed – Measured in PPM (pages per minute)
      • Type – Laser or Ink Jet
    • Monitors
      • Size – Measured diagonally in inches (9″,21″)
      • Resolution – Measured in pixels (1920×1080)
      • Type – LCD/TFT uses a flat panel of coloured cells to change the colour of the light shining through it. OLED uses a  matrix of tiny LEDs to produce an image.
  • processor type – How many bits can be processed in a single operation (16bit, 32bit, 64bit )
  • number of processors – Single Core, the processor can appear to do more than one thing at a time using time slicing.  Multi core, different processes are run on different cores.
  • Processor speed (Hz) – The number of times per second the processors voltage is switched, this allows the processor to carry out an operation. Typically measured in Gigahertz (GHz).
  • memory
    • RAM – Volatile, losses contents when power disconnected. Dynamic, requires constant refreshing to remember contents.
    • ROM – Non Volatile, contents kept when power disconnected. Not writeable, contents can not be changed.
    • cache – Located on (or very near) processor. Static, contents do not need refreshing.
  • device type
    • Desktop – Used for tasks that require a fair amount of processing power and storage.
    • Laptop – Portable devices that use a battery and keyboard.
    • Tablet – Ultra Portable device that uses a battery and touch screen.
    • Smartphone – Small Ultra Portable device that uses a batter and small touch screen.

Higher – Coding (Revision)

Scripting

Including sections of program code in your website, to help make it more dynamic or interactive, is called scripting.

Client-side scripting

  •  A section of code is sent to the client computer and executed there, in the browser.
  • It is commonly used to add interactive elements to a webpage.
  • JavaScript is a language commonly used for client-side scripting.

Server-side scripting

  • A section of code is executed by the web server.
  • It is commonly used to create dynamic webpages, often connected to a database on the server.
  • Popular languages for server-side scripting include PHP, ASP, Perl and ColdFusion.

SEO (Search Engine Optimisation)

SEO is the process of improving the ranking of your webpage in search engine results, in order to increase traffic.

Some SEO techniques include:

  • Making sure each page of your site has a unique, concise and descriptive title contained in the <title> tag.
  • Using the description <meta> tag to include a summary of each page.
  • Using concise URLs.
  • Submit an XML sitemap to the companies which run the search engines
  • Using brief, descriptive filenames and alt text for images

Search engines and web crawlers

  • A web crawler (aka spider) is a piece of software which follows links from web page to web page, analyses the text on each page, and indexes the pages with related keywords.
  • Search engines then use this index to find relevant pages when you carry out a search.

Optimisation of code

Load times of webpages affect traffic. By making code more efficient, file sizes, and therefore load times, can be reduced.

Some techniques include:

  • Using a single CSS file to hold all the formatting information for the site.
  • Putting all JavaScript into a single external file, to reduce fetches from the server.
  • Remove/reduce internal commentary and white space.

Thank you to C O’Toole & A Madill from Braidhurst High School for allowing me to edit and publish this here.