Topic 4

• Storage devices and media evaluation characteristics:

  • Capacity
  • Speed
  • Portability
  • Durability
  • Reliability
  • Cost
• RAM is a type of primary storage with fast data rate but is volatile

  • Non-volatile storage devices include optical, magnetic, and solid-state storage
• Secondary storage is not directly accessible by the CPU

  • It is non-volatile, retaining data even without power
  • Secondary storage devices can be internal or external to the computer
• Uses of secondary storage:

  • Storing programs and data on hard drives
  • Distributing films using Blu-rays
  • Transporting data with memory sticks
  • Backup using magnetic tape or external hard drives
  • Additional storage on cameras and smartphones with SD cards
• Storage types:

  • Primary storage: RAM and ROM
  • Secondary storage: HDD, SSD, offline storage like CD, DVD, BluRay, flash memory, SD cards, removable HDD/SSD, magnetic tape
• Storage methods:

  • Magnetic: Mechanical parts move over disks to read/write data magnetically
  • Optical: Lasers read/write data using light
  • Solid State: Data recorded onto solid memory chips without moving parts
• Magnetic disks:

  • Contain concentric circles called tracks
  • Tracks divided into sectors
  • Disk heads read/write data
  • Hard disks have solid platters, while floppy disks have soft plastic disks
• Magnetic storage - hard disks:

  • Used in many PCs and laptops
  • Large storage capacity, up to 6TB or more
  • Cheap compared to SSDs
  • Portable hard disks connect via USB for backup or data transport
• Optical storage:

  • Data stored as pits and lands burnt or pressed into a spiral track
  • Laser beam reads pits and lands for data retrieval
• Advantages of optical storage:

  • Cheap, easily portable, takes up little space
  • Disadvantages include less storage capacity, easily damaged, slow write speeds
  • Used for songs, videos, backup, and archiving data
• Solid State Drives (SSD):

  • Use non-volatile flash memory for storage
  • Very fast read/write speeds, durable with no moving parts
  • More expensive than HDDs but faster and durable
• Advantages/disadvantages of SSDs:

  • Highly durable, fast read/write speeds, no moving parts
  • More expensive than HDDs, similar storage capacity
  • Used in higher-end computers, laptops, smartphones, and tablets
• Flash memory:

  • Low cost, portable, durable with no moving parts
  • Ideal for cameras, mobile phones, USB memory sticks
• Storage characteristics:

  • Capacity: Amount of data stored
  • Speed: Rate data can be read/written
  • Portability: Ease of carrying
  • Durability: Resistance to damage, extreme conditions
  • Reliability: Likelihood of data loss
  • Cost: Price of the device and cost per unit of data stored
• Data capacity:

  • Different storage devices have varying storage capabilities
  • Higher capacity allows greater data storage
  • Choosing a storage device depends on storage requirements
• Calculating data capacity:

  • Knowing required capacity helps choose appropriate storage device
  • Example: Storing 5000 photos with 10MB each requires 50GB
  • Suitable storage devices depend on data size and usage
• Plenary:

  • Examples of storage devices: HDD, SSD, CD drive, USB flash drive, SD card
  • Characteristics: Capacity, speed, portability, durability, reliability, cost
  • Technologies: Magnetic, optical, solid state
  • Volatile vs. non-volatile data, 1 Terabyte = 1000 Gigabytes