3.3 Storage Devices

Question 1

Hard Disk Drives (HDD)

Answer 1

• non volatile magnetic storage
• random access
• spinning platters with moving actuator arm
• moving parts eventually break

Question 2

Drive Sizes (Form Factor)

Answer 2

HDD:
- 3.5 inch, 2.5 inch for laptops
SSD:
- 2.5 inch or 1.8 inch (uncommon)
- mSATA
- M.2: smallest form factor, sizes vary

Question 3

HDD Speeds

Answer 3

5400 rpm
7200 rpm
10000 rpm
15000 rpm

Question 4

Solid State Drive

Answer 4

• non volatile
• no latency from moving parts
• very fast
• 2.5 inch SATA
• can also be mSATA or M.2 form factor

Question 5

mSATA

Answer 5

• smaller SSD form factor
• replaced by M.2

Question 6

M.2

Answer 6

• smaller form factor SSD
• sizes vary
• single connection to motherboard, no external power required
• SATA or NVMe
• B key: 2 lanes of bandwidth
• M key: 4 lanes of bandwidth

Question 7

NVMe

Answer 7

Non-volatile Memory Express
- newer storage access and transport protocol
- used by M.2
- faster than SATA
- lower latency, supports higher throughput
- PCIe connection

Question 8

SATA

Answer 8

• protocol for how data is transferred between the motherboard and storage devices
• originally designed for HDDs
• supported by some SSDs
• uses AHCI to move drive data to RAM

Question 9

PCIe

Answer 9

• type of connection for data transfer
• lower latency and high data transfer rates
• used by M.2 with NVMe

Question 10

Flash Drives and Memory Cards

Answer 10

• non-volatile
• limited number of rewrites
• USB, SD, miniSD, microSD, CompactFlash, xD (proprietary card used in older digital cameras)

Question 11

Optical Drives

Answer 11

CD
CD-R (recordable)
CD-RW (rewritable)
DVD
DVD-ROM DL (dual layer) or DS (double sided)
Blu-ray Disc (BD)

CDFS is the file system for optical media

Question 12

RAID

Answer 12

Redundant Array of Independent Disks
- drive configuration for data redundancy
- different levels

Question 13

RAID 0 - Striping

Answer 13

• file blocks (data) is split between two or more physical drives = faster speed
• no redundancy

Question 14

RAID 1 - Mirroring

Answer 14

• file blocks are duplicated between two or more physical drives
• required disk space is doubled
• if one drive fails, the other drive still has the data

Question 15

RAID 5 - Striping with Parity

Answer 15

• at least 3 physical drives
• data is split along with a parity block
• parity allows computer to rebuild data if any drive fails
• you will lose data if more than 1 drive fails

Question 16

RAID 10 - Striping Mirrors

Answer 16

• at least 4 physical drives
• data is striped between 2 mirrored pairs
• speed of striping, redundancy of mirroring
• “nested” meaning that it is a hybrid RAID (combines RAID 1 and 0)

Question 17

Which storage devices are hot swappable?

Answer 17

SATA
eSATA
USB