3.3 - Data Storage Flashcards
What are the two distinct groups that memory and storage devices are split up into? [2]
- primary memory
- secondary storage
What is the main difference between primary memory and secondary storage? [2]
- PM is directly addressable by the CPU whereas SS is not directly addressable by the CPU
What does the PM include? [2]
Random Access Memory and Read-only Memory
What is RAM? [2]
- working area of the computer
- data currently being used is temporarily stored
What is ROM? [2]
- contains data that cannot be changed or written to
- needs to be stored permanently
What are the differences between RAM and ROM? [2]
- RAM = temporary whereas ROM = permanent
- RAM = volatile memory whereas ROM = non-volatile
What is secondary storage? [2]
- not directly accessed by
the CPU - is necessary for more permanent storage of data
What are examples of secondary memory? [3]
- HDD
- SSD
- DVD
What are the 2 types of RAM? [2]
- SRAM
- DRAM
What is SRAM? [2]
- it makes use of flip flops which holds each bit of memory
- it doesn’t need to be constantly refreshed
What is DRAM? [2]
- contains transistors and capacitors
- it needs to be refreshed constantly
What are the differences between SRAM and DRAM? [4]
- SRAM is more expensive whereas DRAM is less expensive
- SRAM uses transistors whereas DRAM uses capacitors
- SRAM has a faster data access time than DRAM which has less
- SRAM has less storage capacity than DRAM which has a higher capacity
Why is ROM needed in a computer? [1]
- they are used to store information that the computer needs to access when powering up for the first time
What are the 3 types of secondary storage? [3]
- solid state drive
- magnetic drive
- optical drive
What are magnetic harddrives? [2]
- uses platters which are divided into tracks and sectors
- data is read and written
using electromagnets
What is SSD? [3]
- contains no moving discs
- uses NAND or NOR technology
- transistors are used as control gates
and floating gates
What are the differences between SSD and HDD? [4]
- HDD has moving parts whereas SSD has no moving parts
- The moveable parts cause friction and heat generation which makes HDD slower and the SSD uses NAND chips which are faste
- HDD is less expensive and SSD is more expensive
- HDD has more storage whereas SSD has less storage
What is Optical storage? [1]
- uses lasers to create and read pits
and lands
What are examples of Optical Storage? [3]
- CD
- DVD
- Blu-ray Disc
What are the differences between the 3 types of Optical Storage? [4]
- Blu-ray has the highest storage capacity, then DVD then CD with the lowest
- CD has the highest laser wavelength, then DVD then Blu-ray with the lowest
- Blu-ray has the fastest data transfer speed, then DVD and then CD with the slowest
- Blu-ray is the most expensive and then DVD and then CD being the cheapest
What are the uses of CD? [2]
- audio files
- small software
What are the uses of DVD? [2]
- movies
- larger data files
What are the uses of Blu-ray discs? [2]
- HD movies
- games
What does a pit and a flat area represent? [2]
- pit = 0 = no light
- flat area = 1 = reflected light
What are the advantages of using cloud storage? [3]
- access data any time
- easily adjust storage capacity
- it is cheaper compared to buying local hardware
What are the disadvantages of using cloud storage? [3]
- needs internet access
- can be hacked
- long term costs add up as subscription is needed
What colour laser do the 3 types of Optical Storage use? [3]
CD - infrared laser
DVD - red laser
Blue-ray - blue laser
