Facebook & Privacy

As shown in the video, that privacy setting are not always actually private. Facebook will take photo's and statues and use them to make money by selling them to large corporate company's. What schools and parents should actually be teaching us how to jail break and hack and similar things to teacher the public how to make and set privacy settings that will keep our data safe 

1.4c Secondary Storage Media

Differences:

• Optical vs. Magnetic
• Max Size
• Sequential vs. Direct Access
• Read Speed
• Portability

1.4b Types of Primary Memory

ROM (Read-only)

Small permanent memory that holds a small program called the bootstrap - Looks for OS when "Booting"

RAM (Random Access Memory)

• Holds OS / Data / Programs that are IN USE.

• Emptied when PC is switched off.

ROM
  - Non-volatile (Doesn't Change)
RAM 
- Volatile (Able to Change)

1.4a Control Unit, Memory Unit, and Arithmetic Logic Unit

Arithmetic Logic Unit:

• Does Maths
• Works out Logic (IF, Else)
• Holds I/O while Control unit decides what to do

Memory Unit (Stores)

• Holds all the instructions to be used
• Holds all the data to be used

Control Unit

• Decides next instruction
• Gets it
• Deciphers it
• Tells the other parts what they need to do.

1.3j Back up vs Archiving

Backing up

• Store data for current data that may be required data that they are currently need (Short term)
• Backs up data that can be accessed fast
• done as often as possible

Archiving

• Done less frequency
• Cheaper media
• long term

1.3g Different Storage Types

Saving to serial storage:
Tape

• No storage
• slow to load
• takes to long to find data
• Brilliant for saving
• order that they arrive are saved
• cheapest method of saving
• physical method of storage

Sequential

• looks whats on the and saves in order
• slows down saving
• much quicker to find data

Index Sequential

•  Very fast
• Access to data that uses index's through different menus
• On credit card = hashing algorithm

Example:
Credit card

• type of card- 
1. visa 
2. country
3. banks
4. branches

Random Access

• following a hashing algorithm to decide where to store every piece of data is stored in a specific
• If it is not complicated enough it can result in clashes
• Fast

1.3 Fixed length records

Each field limited to:

• Name -
• 255

• Age - 
• 8 (Int)

• Price - 
• 16 (Dec)

• Boolean - 
• 1 bit