CHAPTER 8 AND 9

CHAPTER 8 :STORAGE

A storage device is the hardware that records and/or retrieves items to and from storage media

Capacity is the number of bytes a storage medium can hold.

Items on a storage medium remain intact even when you turn off a computer or mobile device

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

Hard disks can store data using longitudinal recording or perpendicular recording

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) has several advantages over magnetic hard disks:

• Higher storage capacity
• Faster access time
• Faster transfer rates
• Quieter operation
• More Durable
• Light weight
•  Less power consumer
• Less heat generation
• Longer life

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

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

• A CD-ROM can be read from but not to written 
• A CD-R is an optical disc on which user can write once, but not erase
• A CD-RW is a erasable multi session disc

Enterprise Storage

Enterprise storage is a centralized repository for business information that provides common data management and protection, as well as data sharing functions, through connections to numerous (and possibly dissimilar) computer systems

Enterprise hardware allows large organizations to manage and store data and information using devices intended for heavy use, maximum efficiency, and maximum availability

Network attached storage (NAS) is a server that is placed on a network with the sole purpose of providing storage to users, computers, and devices attached to the network

A storage area network (SAN) is a high-speed network with the sole purpose of providing storage to other attached servers

Other Types of Storage

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

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

Operating System Functions

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

How an operating system handles programs directly affects your productivity

• Single tasking and multitasking
• Foreground and Background
• Single user and multi user

Memory management optimizes the use of the computer or device’s internal memory

Virtual memory is a portion of a storage medium functioning as additional RAM

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

Types of Operating Systems

Desktop Operating Systems

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

Mobile Operating Systems

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