5.2 - Data Storage Flashcards
3 groups of memory storage devices
Primary memory
Secondary storage
Offline storage
Examples of internal secondary storage (2)
HDD (Hard Disk Drive)
SSD (Solid State Drive)
Examples of external secondary storage (5)
DVD
CD
DVD - RAM
Blu-ray disk
USB
Difference between primary memory and secondary storage (5)
primary memory directly addressable by CPU while secondary storage not
Secondary storage is all non-volatile
secondary storage can be external or internal to computer
Primary storage faster to access than secondary storage
primary stores less data than secondary
Function of primary memory
allows CPU to access applications/services temporarily stored in memory locations
Can RAM be written to
yes
Can RAM be read from
yes
Function of RAM (4)
store data
store files
store part of application currently in use
store part of operating system currently in use
Is RAM temporary or permanent
temporary - data can be changed by user or computer
Is RAM volatile or non-volatile
volatile - memory contents lost when powering off computer
What are the 2 types of RAM technology (2)
DRAM (Dynamic RAM)
SRAM (Static RAM)
Which RAM does Cache use
SRAM
How does SRAM work
uses flip-flops which hold each bit of memory
SRAM and DRAM differences (6)
SRAM more expensive
SRAM more power
DRAM for main memory while SRAM for cache
SRAM faster
DRAM stores more bits per chip
DRAM needs to be recharged to maintain data while SRAM holds data as long as there is power
ROM features (4)
non-volatile - data not lost once computer powered off
ROM is permanent - cannot be changed or written to
contents can only be read
often used to store instructions a computer needs to access when powering up
When is ROM used
BIOS (basic input and output system)
Differences between RAM and ROM (4)
RAM is a temporary memory device while ROM is a permanent memory device
RAM is volatile while ROM is non-volatile
RAM can be written to and read from but ROM cannot be altered
RAM used to store data currently in use while ROM stores data needed to start up
3 types of technology for secondary (and off-line) storage (3)
magnetic
solid state
optical
What technology does HDD use
magnetic
Disadvantages of HDD (2)
hard disk can have slow data access when compared to RAM
can have latency - time delay
Do SSDs have moving parts
no
Benefits of SSDs over HDDs (5)
no moving parts - more reliable/less damage
lighter
thinner
data is faster than HDD
lower power consumption
Drawbacks of SSD (2)
does not last long
is usually not used in servers
Benefits of memory sticks (2)
small for transferring files between computers
can be used as small back-up devices
How does virtual memory work
moves oldest data out of RAM into HDD when RAM is full
Benefits of virtual memory (3)
programs larger than RAM can still be executed
reduces need to buy more RAM
doesnt waste memory with data not being used
Drawbacks of virtual memory (2)
disk thrashing - system too busy moving data in out of memory to do anything
slower as it is using data from secondary storage
How does cloud storage work (3)
data stored on remote servers
same data stored on more than one server - clients can access data at any time
owned and managed by company
Cloud storage benefits (5)
file can be accessed as long as there is internet
customer does not need same computer or to carry external storage device with them
cloud provides back-up
cloud storage can recover data
cloud offers almost unlimited storage capacity
Cloud storage drawbacks (3)
unstable internet can cause problems accessing files
can be expensive if large storage capacity required
cloud storage can fail and lose all data
Examples of SSD (3)
SD card
RAM
USB flash memory drive
Software stored on SSDs (3)
operating system
application software
utility software
Examples of what is stored in primary memory (5)
BIOS
start-up instructions
programs currently in use
data currently in use
par of OS currently in use
Purpose of the secondary storage (4)
permanently stores data
loads application software
loads operating system
allows user data to be accessed
How does an SSD store data (6)
uses NAND/NOR technology/flip-flops
stores data by flashing it onto chips
controls flow of electrons using
transistors
electric current reaches control gate
current flows through to floating gate to be stored
when data is stored transistor is converted from 1 to 0
Which of these (HDD, SSD, USB) has no moving parts
SSD
USB
Which of these (HDD, SSD, USB) is non-volatile
HDD
SSD
USB
Which of these (HDD, SSD, USB) can use NAND gates to store data
SSD
USB
Which of these (HDD, SSD, USB) uses magnetic properties to store data
HDD
Which of these (HDD, SSD, USB) has the smallest physical size
USB
Which of these (HDD, SSD, USB) has the slowest read/write speeds
HDD
How HDD stores data (7)
has platters
platters divided into tracks
platter spun
read/write arm moves across storage media
read/writes data using electromagnets
uses magnetic fields to control magnetic dots of data
magnetic field determines binary value
What does primary memory contain (3)
RAM
ROM
Cache
