CHAPTER 8 & 9

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