The ICT Lounge
Section 3.1:
Data Storage and Backing up Data
In this section you will see what is meant by the terms 'data storage' and 'backing up data'.

We also discuss why it is very important that data is backed up and briefly look at some circumstanses that can destroy our data.

Key Concepts of this section:
Know what is meant by 'Data Storage'.
Understand the difference between temporary storage and permanent storage.
Be able to discuss why it is important to back up data.

Data Storage (what is it?)
Key Words:
Data, Storage, Save/Write, Open/Read, RAM, Permanent, Volatile, Non-Volatile
"Data Storage is where we put data in a ‘known’ place (Save) which we can come back to later and get the data back again (Read)"

Overview of Data Storage:
Storage devices can be saved on and read from.
RAM can only store data whilst computer has power. USB sticks store data permanently.
Without storage devices we could not run operating systems, programs or save our work.

Our computers would be be completely useless!
There are some terms that you need to be aware of when we talk about data storage:

Writing of data =
Storing data (also known as saving)
Reading data =
Getting our data back (also known as opening)

Data can either be stored temporary or permanent.
  • RAM (computer memory) is used to store data temporarily
  • Backing Storage Devices are used to store data permanently.
The difference between these are explained below:

RAM (computer memory)
Backing Storage Device
Data is temporarily stored.
Data is permanently stored.
Volatile - data is erased when computer is switch off.
Non-Volatile - data is not erased when computer loses power.
Used to only store data that is currently in use.

(e.g. open programs and unsaved files)
Used to store data long term.

(data is only erased when we manually choose to delete it)
Very fast reading/writing of data.
Slower reading/writing of data.
Examples of permanent storage devices include hard disk drives, DVD's and flash memory sticks.

The image below shows where storage devices fit into a computer system:

This diagram shows where storage devices fit into a computer system.

Backing up Data
Key Words:
Backup, Copy, Medium
"Backing up is the process of using a storage device to copy files and data to a different storage medium in case of a problem with the original copy"

Overview of Data Backups:
Backing up data just means to 'make copies' of files.
DVD drives are 'Storage Devices' that are used to read/write data onto DVD discs.
DVD discs are example of 'Storage Medium' and these hold the data.

Backing up of data is simply the process of making copies of your files.

To back up data you need 2 pieces of equipment:
  • Storage Device - The hardware that saves (writes) or reads the data from the storage medium. (DVD Player for example)
  • Storage Medium - The hardware that actually holds the data (Memory Sticks, Hard Disk Drives, DVD Disks etc)

Backing up is considered 'good practice' and helps prevent us from losing our work and files.

There are many ways we can lose computer files. We could accidentally delete them, files could be infected with a virus or someone could even deliberately erase our files!

Backups of files should be stored in a different location to the original.

This is to ensure we have safe copies in the event that the originals are destroyed by fire or floods etc.

If the backups were in the same location as the originals then the fire would destroy the backups as well!

Why Backup Data?
There are many reasons why backups are made. Some of the common reasons are summarised below:

Original data could be accidentally copied over or deleted.
Data could be lost due to damage to the original storage device.

For example: You hard disk drive could stop spinning.
You could lose your original storage device.

For example: Your laptop could get stolen or you could misplace a memory stick.
Hackers could access our data and delete it (or change it)
Original storage device could be destroyed in a fire.

Note: Backups don't help prevent data loss in the event of viruses. if the original file had a virus BEFORE the it was backed up then the copy will also be infected.