• Solid State Drive (SSD)
  • Hard Disk Drive (HDD)

HDD

  • Header
  • Tracks
  • Sectors
  • Head
  • Speeds for reading/writing
  • Format sizes

SSD

  • All data is statically stored
  • Much faster
  • 2.5 Inch
  • mSATA
  • M.2 chips
  • Difference Inerfaces for Connections

Price

  • SSDs cost more than HDD
  • Cheaper SSDs implement less reliable multi-level call (MLC) memory technoogy
  • Expensive ones use signle-level call (SLC) technology

Hybrid Drives

  • Combine flash memory and spinning disks
  • Needs to take advantage of the hardware and interfaces availabile on the motehr board

PATA Drives

  • 40-bin ribbon cables called IDE Cables

SATA drives

  • Point-to-point connection between SATA drives
  • Much faster than PATA
  • 1.0: 1.5 GBps/150 MBps
  • 2.0: 3 Gbps/300 MBps
  • 3.0: 6 Gbps/600 MBps
  • 3.2 up to 16 Gbps/2000 MBps, also known as SATAe

eSATA

  • External can be used as Hard DRives
  • faster than USB 2.0
  • Cable length 2 meters

AHCI

  • Advanced Host Controller Interface (AHCI) is efficient way to work with SAT devices
  • Must be implmeneted in the Operating System

Volatile Memory Express NVMe

  • Supports communication between the Operating System and the Solid State Drive directly
  • This is through a PCIe bus lane, reducing latency and taking full advantage of the wicked-fast speeds of high-end SSDs

Small Computer System Interface (SCSI)

  • Serial attached hard drives provide fast and robust storage for servers and storage arrays
  • Can provide speeds up to 12 Gbps
  • Also supports SATA drives

Protecting Data

  • Disk Mirroring
    • One drive works as the primary and another as the secondary
  • Duplexing: Same as mirroring, but separate controller for each drive - faster and more redundant
  • Disk Striping: Spreading the data among multipel (at least two) drives

RAID

  • Raid 0 - Disk Stripping Disk striping requires at least two drives
  • RAID 1 - Disk Mirroring/Duplexing RAID1 arrays
  • RAID 5 - Disk stripping with Distributed Parity instead of dedicated data and parity drives
  • RAID 6 - Disk stripign with extra parity if you lose a hadr drive in a RAID 5 array
  • RAID 10 - Nested, Striped Mirrors RAID levels have been combined
  • RAID 0+1 - Nested, Mirrored Stripes LIke RAID 10