1.4 Flashcards
(16 cards)
What is secondary storage ?
Long term storage of data even when device powered off
Why is secondary storage needed ?
For long term storage of data, when device powered off
To store data
For transferring data
What must you consider when selecting a secondary storage device?
Capacity
Speed
Portability
Reliability
Durability
Cost
Two different magnetic disk drive names ?
Internal Hard Disk
Portable Hard Disk
Features of Internal Hard Disk
Physical Size: Large Physical Size
Cost: £15/TB
Capacity: Large Capacity
Data Transfer Speed: Fast (100-200MB/s)
Portability: Not portable, built in to PC
Durability : good when disk not in use, but vulnerable to movement when spinning. Affected by heat and magnetic fields
Reliability: Extremely reliable
Typical Use : Inside PC as secondary storage
Features of Portable Hard Disk
Physical Size: Large, but smaller than internal hard disk
Cost: £15/TB
Capacity: High
Data Transfer Speed: High (100-200 MB/s
Portability: can fit in a large pocket
Durability: good when disk not in use, but vulnerable to movement when spinning. Affected by heat and magnetic fields
Reliability: extremely reliable
Typical use: supplementary storage for a PC
What is HDD ?
Hard Disk Drive
Magnetic storage devices
Why SSD is better than HDD ?
More reliable, as they are less susceptible to shock and damage as they have no moving parts
More portable as they are considerably lighter
Faster access times because they don’t have to wait for the head to move and for the drive to spin
Lower power consumption
Cool
Can be very thin as they have no moving parts
Name three SSD devices ?
Internal Solid State
USB Memory Stick
Memory Card
Internal Solid State features?
Cost: £100/TB
Capacity: up to 4TB
Data Transfer Speed: up to 3.5GB/s
Portability: not portable, built into PC
Durability: 5-10 times more durable than hard disks as no moving parts
Reliability: extremely reliable
Typical Use: PCs, notebooks, tablets, laptops
Features of USB Memory Stick
Cost: £80/TB
Capacity: 16MB to 256GB
Data Transfer Speed: 3-100MB/s
Portability: very small and portable
Durability: very durable
Reliability: very reliable, but can corrupt files if removed from PC too soon
Typical Use: personal use, moving files between computers
Features of Memory Card?
Cost: £120/TB
Capacity: 32GB to 1TB
Portability: very small, designed for portable devices
Durability: very durable, not sensitive to temperature or knocks
Reliability: very reliable
Typical Use: in phones and cameras
Name three different Optical Storage Devices?
CD
DVD
Blu-ray
Features of CD
Cost: £400/TB
Capacity: 640MB
Access Speed: up to 7.6MB/s
Portability: easy to carry in a large pocket or bag
Durability: depends on how it is stored, quality will degrade over time. Life expectancy of 10-25 years
Reliability: good for medium term but degrades over time
Typical use: CD-ROM for software distribution
Features of DVD
Cost: £48/TB
Capacity: 4.7 GB (single layer)
8.5GB (dual layer
Access Speed: 16MB/s
Portability: easy to carry in a large pocket or bag
Durability: depends on how it’s stored. Qualify will degrade over time. Life expectancy of 10-25 years
Reliability: good for medium term but degrades over time
Typical Use: DVD is used as a back-up device but also for software distribution; games and movie storage too
Features of Blu-ray
Cost: £17.60/TB
Capacity: 25GB (single layer)
50 GB (dual layer)
Access speed: 50MB/s
Portability: easy to carry in a large pocket or bag
Durability: depends on how it is stored, quality will degrade over time. Life expectancy of 20-100 years
Reliability: good for medium term but degrades over time
Typical Use: storing movies and games, can be used as a back-up device
