memory and storage Flashcards
(58 cards)
what are the different types of storage
- primary storage
- secondary storage
- tertiary storage
what are the differences between primary and secondary storage
- primary storage is volatile with the exception of ROM while secondary storage is non-volatile
- primary storage has a small capacity compared to secondary storage while secondary storage has a much larger storage capacity
- primary is much faster to access from than secondary
what is the need for primary storage
primary storage hold the data and instructions which the CPU needs access to while the computer is running and the CPU can access data from primary storage much faster than secondary
what is ROM
- small piece of read only memory located on the motherboard
- contains very first instructions for the computer
- loads the BIOS or bootstrap
what is RAM
- temporary storage of instructions and data
- hold information being executed by the processor
- volatile
- faster than the hard disk
what happens when a computer runs out of RAM
instructions that are not being used are transferred to a space on the hard disk
- known as virtual memory
what happens when you turn your computer on
- first it gets its initial instructions from the bootstrap contained on the ROM
- once this is complete instructions from the hard drive can be loaded into main memory (RAM)
where are instructions and data stored when you shut down your computer
on the hard drive as it in non-volatile, has a lot of capacity and also read + write
why is secondary storage needed
- storage of programs and data when the power is turned off
- semi-permanent storage of data that can change
- backup of data files
- archive of data files
what are the 3 common types of storage devices
- magnetic
- optical
- solid state
what are optical storage devices used for
to store music and images (for example movies)
how do optical storage devices work
by shining a laser at the media and processing the reflection from the media
what are the different types of optical storage devices
- CD-R
- CD-RW
- DVD-R
- DVD-RW
- Blu-Ray
what are the advantages of optical storage devices
- cheap
- light weight
- portable
what are the disadvantages of optical storage devices
- slow access times
- prone to scratches
what are the advantages of magnetic storage devices
- cheap
- large capacity
what are the disadvantages of magnetic storage devices
- slow access time
- fragile
- has moving parts
- perform better when defragmented
what are solid state drives
a piece of flash memory which operates without noise and are beginning to replace hard disks
how do solids-state drives work
they work by a flow of electricity forcing electrons into floating gates between two oxide layers
what are the advantages of solid-state drives
- durable
- fast access time
- no moving parts
- low power
- no need to defragment
what are the disadvantages to solid-state drives
- quite expensive
- limited number of read/write cycles
what are the requirements when deciding on which device to use given an application
- capacity
- speed
- portability
- durability
- reliability
- cost
when is optical storage suitable
- suitable for read only data distribution
- suitable for small capacity situations
when is magnetic storage suitable
- suitable when very high data capacity is required
- suitable for fast access to data
- suitable for low cost situations
- suitable for cloud storage on server farms
