1.1.3 Input, output and storage

Question 1

What are input devices?

Answer 1

• Devices that can be used to recieve external data and transfer it to the computer

Question 2

What are output devices?

Answer 2

• Devices which can take data from the computer and transfer it to the user

Question 3

What are the types of secondary storage?

Answer 3

• Flash
• Magnetic
• Optical

Question 4

How does optical storage work?

Answer 4

• Read from and written to using lasers
• Binary information represented by portions of the disc which either reflect or scatter the incident laser light:
• A pit scatters light and represents a 0
• A land reflects light and represents a 1
• Pits and lands are written in spiral tracks on the disc’s surface

Question 5

What are the three types of optical storage?

Answer 5

• CD
• DVD
• Blu-Ray

Question 6

What are the properties of the three types of optical storage?

Answer 6

CD:
* Stores small quantities of information
* Small,thin and light so easilty portable
* Easilty damaged by scratches
* Relatively low transfer speeds
DVD:
* Higher storage capacity than CDs
Blu-Ray:
* More than five times as much storage than traditional DVDs

Question 7

How does magnetic storage work?

Answer 7

• Represent binary information using two magnetic states:
  Polarised
  Unpolarised
• Most common type is hard disk drives
• Magnetic tape also stores information magnetically

Question 8

What are the types of magnetic storage?

Answer 8

• Hard disk drives
• Magnetic Tape
• Floppy disks

Question 9

How does flash storage work?

Answer 9

• Logic gates used to store charge in one of two states: high or low
• Information is stored on blocks, combined to form pages
• Can be erased and reprogrammed electronically
• Is non-volatile

Question 10

What are the properties of the 3 types of magnetic storage?

Answer 10

Hard Disk Drives:
* High capacity
* Rotate disc at high speeds to read/write information
* Somewhat slow data transfer speeds
* Many moving parts means easily damaged by storage
Magnetic tape:
* Long stretches of type wound onto reels passed through readers
* Space consuming way of storing data
Floppy discs:
* Thin magnetic disc enclosed in plastic to protect it from dust and dirt
* Thin and light weight making it very portable
* Low storage capacity (1MB)

Question 11

What is the type of flash storage?

Answer 11

SSD

Question 12

What are the properties of SSDs?

Answer 12

• Extremely light and portable
• No moving parts
• High data transfer rates
• Main disadvantage is cost
• Limited lifespan

Question 13

What is the role of primary storage?

Answer 13

• Stores information like code instructions to execute the files which are required by running programs

Question 14

What are the types of primary storage?

Answer 14

• RAM
• ROM

Question 15

What are the properties of RAM?

Answer 15

• Random access memory
• Type of fast volatile memory
• Stores currently running programs
• Faster than secondary memory
• More expensive than secondary memory

Question 16

What are the properties of RAM?

Answer 16

• Read only memory
• Non-volatile
• Useful for storing fixed sequences of instructions

Question 17

What is Virtual Storage?

Answer 17

• Storing information remotely so that it can be accessed by any computer with access to the same system, e.g over the internet
• Often an abstraction of multiple drives acting as one

Question 18

What are the advantages of Virtual Storage?

Answer 18

• Doesnt require the purchase of physical storage
• Can be accessed by any device

Question 19

What are the disadvantages of Virtual Storage?

Answer 19

• Transfer speeds are limited by users network speed
• High cost