IGCSE ICT Chapter 3.1 and 3.2

• ICT
• Secondary Education

Objective

1. Explain what is backing up of data and why it is important.

2. Describe what is Serial Access and Direct Access.

3. Create a mind map explaining what is Serial Access and Direct Access.

What is backing up of data?

What is backing up of 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)

Why backup data?

Serial Access

• This method is also sometimes called 'Sequential Access'.
• Data is accessed by starting at the beginning and then searched through, in order/sequence, until the required information is found.
• The need to search from the beginning of the storage medium makes this type of data access very slow.

Examples of storage medium that use serial access are:

• Video cassettes
• Music cassettes
• Backup tape cartridges(hold lots of tape for backing up large amounts of data)

What are the examples of Serial Access Storages?

1. Video Cassettes
2. Music Casettes
3. Tape Carts
4. All of the above

Direct Access

• This method is also sometimes called 'Random Access'.
  
  
• The computer can calculate exactly where the data has been stored and can go straight to it directly (instant access). 
  
  
• The computer knows where all of the data on the storage medium is and so it can access it very quickly.  

What are the examples of Direct Access Storage?

1. USB Memory Sticks
2. Flash Memory
3. Blu-ray Discs
4. All of the above