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CHAPTER 4: SECONDARY STORAGE - Coggle Diagram
CHAPTER 4: SECONDARY STORAGE
STORAGE
holds data, instructions and information for future use
storage medium
the physical material on which a computer keeps data, instructions and information.
storage device
the computer hardware that records and/or retrieves items to and from storage media
involves two processors
a) reading is the process of transferring items from a storage medium into memory.
b) writing is the process of transferring items from memory to a storage medium.
secondary storage
provides permanent or nonvolatile storage
items on a storage medium remain intact even when you turn off a computer or mobile device
important characteristics of secondary storage
media - physical material that holds data and programs
capacity - how much a particular storage medium can hold
storage devices - hardware that reads data and programs from storage media
HARD DISK
contains one or more inflexible, circular platters that use magnetic particles to store data, instructions and information
hard disks use rigid metallic platters that are stacked one on top of another
it stores and organizes files using tracks, sectors and cylinders
two basic types of hard disks
internal hard disk
located inside the system unit
fast access to retrieve large quantities of information
cannot be easily removed from the system unit
external hard disk
slower access
usually connected to a USB or Thunderbolt port on the system unit
easily removed
performance enhancement
disk caching - uses cache and anticipates data needs
RAID - linked, inexpensive hard disk drives
file compression - reduces file size
file decompression - expands compressed files
SOLID-STATE STORAGE
solid-state memory contains no moving parts
data and information are stored and retrieved electronically
types of flash memory storage:
a) solid-state drives
b) memory cards
c) USB flash drives
solid-state drives
a) faster and more durable than hard disk
b) access to slash memory or solid state storage
flash memory cards
a) widely used in laptops, smartphones, GPS
USB drives
a) connect to USB port
b) capacity of 1GB to 256 GB
c) portable
FLASH MEMORY STORAGE
solid-state drive
contains its own processor to manage its storage
memory card
a removable flash memory device that you insert and remove from a slot in a computer, mobile device
USB flash drives
plug into a USB port on a computer or mobile device
OPTICAL DISCS
optical disc consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser
optical disc commonly store items in a single track that spirals from the center of the disc to the edge
track is divided into evenly sized sectors
CD-ROM
single-session disc
CD-R
is an optical disc on which users can write once, but not erase
CD-RW
erasable multisession disc
CLOUD STORAGE
is an Internet service that provides storage to computer or mobile device users
MASS STORAGE DEVICES
to meet the needs of organizations requiring large amounts of secondary storage requirements
devices include
file servers
networked attached storage
RAID systems
organizational cloud storage
ENTERPRISE STORAGE
enterprise hardware allows large organizations to manage and store data and information using devices intended for heavy use, maximum efficiency, and maximum availability
RAID
duplicates data, instructions, and information to improve data reliability
Network Attached Storage
server that is placed on a network with the sole purpose of providing storage to users, computers, and devices attached to the network
storage area network
high-speed network with the sole purpose of providing storage to other attached servers