Secondary storage

What are the three types of secondary storage?

Optical

What is magnetic storage?

Mechanical parts move over the disks surface to read and write data magnetically

What are the basic features of a hard disk (magnetic storage)?

• Disks contains concentric circles called tracks
• Each track is divided into sectors
• Disks heads mounted on mechanical arms read and write the data

Parts of a hard disk drive (magnetic)

components including platters, read/write heads, actuator arms, and spindle motor.

What storage capacity do hard disks have (magnetic)?

Very large storage capacity

How expensive is a hard disk drive (magnetic)?

They are a very cheap form of storage compared to solid state drives

How are portable hard disks (magnetic) connected to a computer?

Via a USB port

What was the primary magnetic secondary storage used at the beginning of the computer's creation?

Magnetic tape

Examples of magnetic storage

Floppy disk

What do cassettes require to be read?

A special tape-drive for reading and writing to the tape

How are magnetic tapes read? What order?

Magnetic tape is read/written sequentially

What is the speed of magnetic storage?

Slow when finding specific data stored on it but
has a Fast read/write speed when in the correct place to begin

How durable is magnetic storage?

When stored properly they are quite durable

What is optical storage?

Lasers read and write data using light

Examples of optical storage

CD

What formats can optical storage appear in?

ROM (read only memory)

How is data stored in optical storage?

Data is stored in pits

How do CD's work?

A laser beam passes over the pits and lands where the level of reflection is measured

What is the difference between CD's and Blu-rays?

A CD has bigger pits and lands as red light has a larger wavelength
The smaller Blu-ray pits and lands allow it to store more data and use a more precise wavelength

How expensive is optical storage?

Cheapest secondary storage

How durable is optical storage?

More durable than magnetic and less durable than solid state

How portable is optical?

Very portable

What kind of capacity does optical storage have?

50GB

What is solid state storage?

Data is recorded onto solid memory chips without any moving parts

How do solid state drives work?

A flow of electricity forcing electrons into floating gates between 2 oxide layers
This causes a change in the charge in the floating gate which can be measured as a 0 or 1
Oxide layers deteriorate over time
They have a limited number of read/write cycles

Examples of solid state

Memory sticks

What are the advantages of solid state storage?

• Very quick access to data
• No moving parts (durable and reliable)
• No noise (great for videoing)
• Low power (doesn't drain your phone battery)
• No need to defragment

What are the disadvantages of solid state storage?

• Limited number of read/write cycles
• More expensive per byte of storage than other types of storage

How expensive is solid state storage?

Very expensive

Is secondary storage volatile?

No