memory/storage Flashcards
define primary storage
Memory that is directly accessed by the CPU
An example is RAM / ROM
RAM stores programs and data that are currently in use and ROM stores boot-up instructions
RAM is volatile and ROM is non volatile
Faster than secondary storage
Is internal to computer
what is secondary storage
non-volatile storage that isn't directly accessed by CPU Stores data / files that can be accessed at a later stage An example is HDD / SSD internal to the computer has a slower access speed
what is offline storage
Non-volatile storage
Off-line storage is storage that is removable from a computer/device/ portable
An example of off-line storage would be CD/DVD/USB stick/SD card
Used to store files as a backup
features of RAM
random access memory stores instructions currently in use It is volatile It is temporary Has a larger capacity than ROM Data can be read and written from (edited)
different types of RAM and explanations
DRAM ‐ needs to be constantly refreshed to retain the data; it uses millions of transistors and capacitors.
SRAM ‐ doesn’t need to be constantly refreshed to retain its data; it uses flip flops.
features of ROM
read only memory stores boot instructions / BIOS It is non-volatile It is permanent Hs lower capacity than RAM Data can only be read from
features of HDD
Hard disk drive stores files / applications Most common method to stored data on pc It uses magnetic properties to store data It has moving parts It is non-volatile storage
advantages of HDD
It is cheap
Can store large amounts of data
Relatively fast write speed
Great longevity
features of SSD
solid state drive Stores files/ applications It has no moving parts It is non-volatile storage It uses flash memory to store data It has a limited number of read/write cycles Sometimes uses EEPROM technology Uses NAND chips When data is stored the transistor is converted from 1 to 0
advantages of SSD
More durable (no moving parts) Very fast (no moving parts) Faster start up time (No Latency) Less noise less heat Smaller portable
features of CD
compact disc Optical storage device Single layer Red laser used to read data Single track Data stored in pits and bumps Smallest storage capacity
features of DVD
Digital Versatile Disc Optical storage device Dual layering Red laser used to read data Stores data in spiral track Single track
features of DVD-RAM
uses concentric tracks
allows for editing
greater longetivity
features of blu-ray
optical storage device Dual layering Read using blue laser Concentric track Largest storage capacity
differences between hdd and ssd
Differences in HDD AND SSD
• HDD has moving parts but SSD does not
• HDD uses magnetic storage whereas SSD uses flash memory
• HDD is slower to access data than SSD
• HDD will create noise/heat, whereas SSD runs quieter/cooler
• HDD has higher power consumption than SSD
• HDD have more read-write cycles whereas SDD has limited number of read-write cycles
• HDD larger in physical size/heavier than SSD
• HDD is normally cheaper for the same capacity of storage as SSD
• HDD is available in a larger storage capacity than SSD
Types of storage devices
Solid state storage
optical media storage
magnetic storage
explain how solid state storage works
It stores data electronically and does not have any moving parts.
It is made of silicon chips.
It uses less power and produces less heat.
It can be found in three types i.e. drives, cards, and modules.
The transfer of data is much faster because of no mechanical parts.
explain how optical media works
laser is used
(Laser beams) shines onto surface of the disk
It is rotated (at a constant speed) to be read
Data is represented on the surface using pits and lands
Pits and lands represent binary values
Pits reflect light back differently (to the area in between/land)
Optical device can determine the binary value from the light reflection
explain how magnetic storage works
Storage device has platters
Platters/disk divided into tracks
Storage platter / disk is spun
Has a read/write arm that moves across storage media
Read/writes data using electromagnets
Uses magnetic fields to control magnetic dots of data
Magnetic field determines binary value
its cheap with high longevity
explain how flash memory works
Uses solid state storage
Connect directly to computer through usb port
Small and lightweight
NAND chips are used
