Chapter 7

• Primary storage


  Volatile storage, loses content when the computer loses power, temporary storage, Random Access Memory (RAM)
• Secondary storage

  Nonvolatile storage, stores programs and data regardless of power, permanent storage
• Secondary storage characteristics


  • Media
  • Capacity
  • Storage devices
  • Access speed
• Writing


  The process of saving information to storage
• Reading


  The process of accessing information from storage
• Hard disks

  • Save files by altering the magnetic charges of the disk's surface to represent 1s and 0s
  • Use rigid, metallic platters that are stacked one on top of one another
  • Store and organize files using tracks, sectors, and cylinders
• How charges on a disk surface store the letter A
• Head Crash


  Occurs when read-write head makes contact with the hard disk's surface or with particles on its surface, disastrous
• Types of Hard Disks

  • Internal
  • External
• Internal hard disks


  Located inside the system unit, used to store programs and data files, routine maintenance and periodic backups recommended
• External hard disks

  Removable, used to complement internal hard disk
• Performance Enhancements


  • Disk caching
  • RAID
  • File compression
  • File decompression
• Solid-state devices (SSDs)


  • Have no moving parts, faster and more durable than hard disks
• Solid-state storage


  • Solid-state drives
  • Flash memory cards
  • USB Drives (or Flash Drives)
• Solid-state drives


  Faster and more durable than hard disks
• Flash memory cards


  Widely used in laptops, smartphones, GPS navigation systems
• USB Drives (or Flash Drives)


  Connect to USB port, capacity of 1 GB to 256 GB, portable
• Optical discs


  • Hold over 128 gigabytes (GB) of data, use reflected light to represent data, lands represent 1s and 0s on the disc, pits are bumpy areas on the disc that, when light is reflected, determine the 1s and 0s, use tracks and sectors to organize and store files but only use a single track unlike the hard drive
• Optical Disc Types


  • CD-ROM
  • CD-R
  • CD-RW
• CD-ROM


  Compact disc - read only, cannot be written to or erased
• CD-R


  Compact disc - recordable, can be written to
• CD-RW


  Compact disc - rewritable, can be written to and erasable
• Cloud Storage


  The Internet acts as a "cloud" of servers, applications provided as a service rather than a product, supplied by servers that provide cloud storage or online storage
• Cloud Storage Services


  • Benefits / Advantages
  • Disadvantages
• Cloud Storage Service Companies
• Making IT Work for You ~ Cloud Storage


  1. Step 1

  2. Step 2
• Mass Storage Devices


  • Enterprise storage system, safe use of data across an organizational network, file servers, networked attached storage (NAS), RAID systems, organizational cloud storage
• Storage Area Network (SAN)


  Architecture to link remote computer storage devices, enterprise storage systems can be connected to, computers to provide local system access, user's computer provides file system, but SAN provides disk space, house data in remote locations and still allow efficient and secure access
• Careers In IT


  • Disaster recovery specialists
  • General employer requirements
• At some point, hard drives will no longer be able to keep up
• New technologies may advance hard drive density to 6.25 TG (6,250 GB) per square inch