CHAPTER 8:DIGITAL STORAGE
Storage
•A
storage medium is the physical material on which a computer keeps data,
information, programs, and applications
•Cloud
storage is another storage option, in which the actual online storage media
used is transparent to the user
•Access
time
measures:
–The amount of time it takes a storage
device to locate an item on a storage medium
–The time required to deliver an item from
memory to the processor
Hard disks
•A hard
disk
contains
one or more inflexible, circular platters that use magnetic particles to store
data, instructions, and information
•Characteristics of a hard disk include:
•A head crash occurs
when a read/write head touches the surface of a platter
•Always keep a backup of your hard disk
•An external
hard disk
is 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
•An SSD (solid state drive)
vs HDD:
•A memory
card
is a
removable flash memory device that you insert and remove from a slot in a
computer, mobile device, or card reader/writer
•USB
flash drives plug into a USB port on a computer or
mobile device
Cloud storage
•Cloud
storage is an
Internet service that provides storage to computer or mobile device users
Optical discs
•An optical
disc
consists of a flat, round, portable disc made of metal, plastic, and lacquer
that is written and read by a laser
•Optical discs commonly store items in a
single track that spirals from the center of the disc to the edge of the disc
•Track is divided into evenly sized
sectors
Other types of storage
•A magnetic
stripe card
contains
a magnetic stripe that stores information
•A 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
CHAPTER 9: OPERATING SYSTEM
Operating System Functions
•An operating
system
(OS) is
a set of programs containing instructions that work together to coordinate all
the activities among computer and mobile device hardware
•Starting Computers and Mobile Devices
–If a computer or mobile device is off,
you press a power button to turn it on
•A user
interface (UI)
controls
how you enter data and instructions and how information is displayed on the
screen
•With a graphical user interface (GUI),
you interact with menus and visual images
•The operating system determines the order
in which tasks are processed
•Operating systems typically provide a
means to establish Internet connections
•Operating systems often provide users
with a variety of tools related to managing a computer, its devices, or its
programs
•Automatic
update
automatically
provides new features or corrections to the program
•A user account enables a use to sign in
to, or access resources on, a network or computer
–A user
name, or
user ID, identifies a specific user
–A password
is a
private combination of characters associated with the user name
•A desktop
operating system is a complete operating system that works
on desktops, laptops, and some tablets
•Windows 8 offers these features:
–Start screen interface with tiles
–Includes the desktop interface
–Support for input via touch, mouse, and
keyboard
–Email app, calendar app, and browser
included
–Enhanced security through an antivirus
program, firewall, and automatic updates
–Windows Store offers additional
applications for purchase
•The Macintosh operating system has
earned a reputation for its ease of use
•Latest version is OS X
•The operating system on mobile devices
and many consumer electronics is called a mobile
operating system and resides on firmware
•Android
is an
open source, Linux-based mobile operating system designed by Google for
smartphones and tablets
•iOS,
developed by Apple, is a proprietary mobile operating system specifically made
for Apple’s mobile devices
•Windows
Phone,
developed by Microsoft, is a proprietary mobile operating system that runs on
some smartphones