1.1.3 Input, Output and Storage

Question 1

How do optical devices store data?

Answer 1

• Read from and written to using lasers. Lands reflect incident laser light, whereas pits scatter it, allowing 1s and 0s to be stored.

Question 2

How do magnetic devices store data?

Answer 2

• A read/write head passes over the region, polarising regions of the metal, or leaving them unpolarised, representing 1s and 0s.

Question 3

How do flash devices store data?

Answer 3

• Information is stored in a block consisting of pages. Each of these stores a charge of high or low, representing 1s and 0s.

Question 4

What are examples of optical devices?

Answer 4

• CDs are small and portable, but easily damaged and have a low capacity and transfer speed.
• DVDs are CDs with higher capacities due to better quality.
• Blu-Rays hold significantly more than DVDs, making them ideal for high quality films.

Question 5

What are examples of magnetic devices?

Answer 5

• HDDs have huge capacities due to their stacked disk platters, but have slow transfer speeds and can be fairly delicate.
• Magnetic Tape is bulky and outdated but good for archiving data.
• Floppy Disks are very portable but outdated and low capacity.

Question 6

What are examples of flash devices?

Answer 6

• SSDs are light, portable, fast and fairly high capacity. They are fairly robust, but have a very high cost and somewhat limited lifespan.

Question 7

What is the purpose of RAM and ROM?

Answer 7

• RAM is a type of fast access main memory. It is volatile, and expensive.
• ROM is small and read only, and used for storing fixed instruction sequences.

Question 8

What is virtual storage?

Answer 8

• Data is backed up and stored remotely over internet-accessed cloud systems. It allows high capacity safe storage at a cost, and also requires a good connection.