Year 10 Computer Science – System Software #7 (Utilities 2)

Starter : Retrieval Practice

Utility software is …

Software that help to maintain or configure a computer.

An example of utility software is encryption. What does encryption software do?

Scrambles data so that it cannot be accessed by third parties. The encrypted data can be decrypted using a special key.

The two main types of operating system are….

Graphical User Interface (GUI) and Command Line Interface (CLI)

Today’s learning: System Software : Utilities (Back Up & Compression)

A reminder that utility system software helps to maintain or configure a computer. Many useful utilities are installed with the operating system, but extra utility software can be installed to perform additional tasks. Here again , is the useful video to give you an overview of the utility software you should be aware of for this course.

We are going to look more closely at ‘back up’ and ‘compression’ utilities …..

Back-Up Utilities

It is important to understand the term ‘back-up’. A ‘back-up’ is a copy of a computer system’s files and setting that is stored externally – this means somewhere elsewhere (not another copy on the computer). This is particular important for organisations and businesses that will inevitably store personal data for staff and maybe customers. All organisations should have a ‘back-up policy’- this will document when and what type of back-ups should be done to prevent loss of data.

Data loss can occur for a number of reasons. Files can easily be accidentally deleted or overwritten. Files can also be damaged through a computer virus, the hard disk might suddenly fail or the computer could be affected by a disaster like a flood or fire.

Back ups can be made manually, for example you can select files and upload them to the cloud, save them to a removable device such as a removable hard drive or a flash memory stick. The issue with this is that the user needs to remember to do this. A better solution might be using a ‘back-up’ utility. A ‘back up’ utility allows the user to:

  • Set up a schedule to back up files at regular intervals e.g. weekly, hourly.
  • What files do back up and what files not to back up.
  • Choose the ‘type’ of back up you require.
  • Where to back up e.g. the cloud, external device.

Types of back-up

There are two types of back-up, these are ‘full back-up’ and ‘incremental back-up’.

A ‘full back-up’ is where all the data is copied every time a back up is done. A full back-up often needs a lot of storage space as you will be making a copy of everything on the hard drive. It will also take a long time to create the back up. However, restoring the data will be much simpler as files are all in one place. Often companies may have a few ‘full back-ups’. Obviously this will take up a lot of storage space.

Source : bbc.co.uk

With an ‘incremental back-up’ , the first back-up is always a complete one, then after that only files that have changed since the the last back-up will be copied. A typical back up strategy might be to do a daily incremental back-up and then do a full back-up on weekly basis. Incremental back-ups use less storage space and are much quicker to create.

A disadvantage of an incremental back-up is that if a full system restore is required, this can take a long time. The last full back up must be restored, followed by every incremental back-up since that point.

Compression Utilities

You may be aware of the term ‘compression’ and talked about this when looking at image /sound file types. As you would expect a compression utility makes a file size smaller. There are a number of advantages of this :

  • less storage space is needed
  • it is faster to download and upload files
  • better performance is achieved when streaming audio or video files (less ‘lagging’ or ‘buffering’)

There are two types of compression:

Lossy compression removes redundant or unnecessary data from a file making the size considerably smaller. Examples are jpeg images or mp3 music files. It is important to say that the decrease in quality of the compressed file is generally not noticeable. It is likely that you take advantage of ‘lossy compression’ if you store music on your phone. An Mp3 file might be typically 4 megabytes, the uncompressed version of the music file might be 100 megabytes.

Source: bbc.co.uk

Lossless compression doesn’t remove data from a file but reorganises it more efficiently. As you can see the lossless compressed file is not compressed as much as lossless compression, but it can be restored to its original state as no data is lost.

A popular lossless compression method is the ZIP file format. Files can be ‘zipped’ and ‘unzipped’ using the compression utility.

Questions based on today’s learning … have a go before you hit the drop down box for the answer!

Describe a full back-up.

A full back up is where a copy is taken of every file on the system.

Give one advantage of a full back-up.

No files are accidentally lost – all files are copied.

Files are easy to restore from as they are all in one place.

Give one disadvantage of a full back-up.

It can take a long time.

It can take a lot of storage space.

Describe an incremental back-up.

Only the files created or edited from the last back up are copied.

Give one advantage of an incremental back-up.

Incremental back-ups are quicker to create.

They take up less storage space.

Give one disadvantage of an incremental back-up.

A disadvantage of an incremental back-up is that if a full system restore is required, then this can take a long time. The last full back up must be restored, followed by every incremental back-up since that point.

Explain the role of the compression utility.

The role of the compression utility is to reduce the size of files so that they take up less disk space, this can allow files to be downloaded /uploaded quicker on the internet.

Describe lossy compression.

Lossy compression removes redundant or unnecessary data permanently from a file making the size considerably smaller. The loss in quality is generally not noticeable.

Describe lossless compression.

Lossless compression doesn’t remove data from a file but reorganises it more efficiently. The lossless compressed file is not compressed as much as lossy compression but it can be restored to its original state as no data is lost.

Want to know more about other types utility software:

https://bbc.in/3cy3zXj

Test yourself !

https://bit.ly/2AwgFaq