CHAPTER 8

CHAPTER 8: DIGITAL STORAGE

STORAGE

- Storage medium is the physical material on which a computer keeps
  data, information, programs and applications

- Cloud storage is the actual online storage media

• Capacity

          - The number of bytes a storage medium can hold

HARD DISK

- Contains one or more inflexible, circular platters that use magnetic 

  particles to store data, instructions and information

• Head crash

          - Occurs when a read/write head touches the surface of a 

            platter

• External hard disk

          - A separate freestanding storage device that connects with 

            a cable to a USB port or other port on a computer or mobile 

            device

FLASH MEMORY STORAGE

• Flash memory chips are a type of solid state media and contain no moving parts
• SSD (Solid state drive) and HDD (hard disk drive)

SSD	HDD
High price(1TB≈RM1000)	Low price(1TB≈RM160-200)
Smaller capacity (max1TB lp/4TB pc)	Big capacity (max4TB lp/10TB pc)
Short lifespan	Long lifespan
Low power consumption (2W)	Higher power consumption (7W)
High speed (200-550Mb/s)	Lower speed (50-120Mb/s)

• Memory card

       

• USB flash drive

   

CLOUD STORAGE

- Internet service that provides storage to computer  or mobile device 

  users

OPTICAL DISC

- Consists of a flat, round, portable disc made of metal, plastic and 

  lacquer that is written and read by a laser

• CD-ROM can be read from but not writable or erasable
• CD-R is an optical disc on which users can write once, but not erase
• CD-RW is an erasable multisession disc
• DVD-ROM is a high-capacity optical disc on which users can read but not write on or erase
• DVD-R or DVD+R are competing DVD-recordable WORM formats, on which users can write once but not erase
• DVD-RW, DVD+RW, and DVD+RAM are high-capacity rewritable DVD formats

OTHER TYPES OF STORAGE

• Magnetic stripe card

          - Contains a magnetic stripe that stores information

• Smart card

          - Stores data on an integrated circuit embedded in the card

• Radio Frequency Identification (RFID)

          - The RFID tag consists of an antenna and a memory chip that 

            contains the information to be transmitted via radio waves

          - An RFID reader reads the radio signal and transfers the 

            information to a computer or computing device

• Microfilm and Microfiche

          - Store microscopic images of documents on a roll or sheet film