3.3 - Storage Devices

Question 1

Hard disk drives (HDD)

Answer 1

• Non-volatile magnetic storage - rapidly rotating platters
• Random-access
  – Retrieve data from any part of the drive at any time
• Moving parts
  – Spinning platters, moving actuator arm
  – Mechanical components limit the access speed
  – Mechanical components can also break

Question 2

Solid-state drives (SSD)

Answer 2

• Non-volatile memory - No moving parts
• Very fast performance - No spinning drive delays

Question 3

mSATA (Mini-SATA)

Answer 3

• Shrink the SATA drive into smaller devices
  – Same data, different form factor
  – Great for laptops and mobile devices
• Smaller than 2.5” SATA drives
  – No spinning drive
  – Allows for different form factors
• Was used briefly - Quickly replaced by the m.2

Question 4

AHCI vs. NVMe

Answer 4

• SATA was designed for hard drives
  – Uses AHCI (Advanced Host Controller Interface) to
  move drive data to RAM
  – SATA revision 3 throughput up to 600 MB/s
  – SSDs need a faster communication method
• NVMe (Non-volatile Memory Express)
  – Designed for SSD speeds
  – Lower latency, supports higher throughputs
  – Take advantage of NVMe with an M.2 interface

Question 5

M.2 interface

Answer 5

• Smaller form factor - No SATA data or power cables
• Can use a PCI Express bus connection
  – 4 GB/second throughput or faster
  when using NVMe PCIe x4
• Different connector types
  – Needs to be compatible with the slot key/spacer
  – B key, M key, or B and M key
  – Some M.2 drives will support both

Question 6

B-key and M-key

Answer 6

• M.2 doesn’t guarantee NVMe
  – Your M.2 interface may be using AHCI
  – Check your documentation
• Your motherboard may only support
  one type of M.2 key
  – Check the documentation again

Question 7

Flash drives

Answer 7

• Flash memory
  – EEPROM (Electrically erasable programmable
  read-only memory)
  – Non-volatile memory - No power required to retain data
• Limited number of writes
  – Can still read the data
• Not designed for archival storage
  – Easy to lose or damage - Always have a backup
  – Flash memory

Question 8

Optical drives

Answer 8

• Small bumps read with a laser beam
  – Microscopic binary storage
• Relatively slow
  – Archival media
• Many different formats - CD-ROM, DVD-ROM, Blu-ray
• Internal and external drives
  – For those uncommon application installations

Question 9

HDD internals (image)

Answer 9