Input Device Dialogue

Chapter 3 Storage

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Learning Objectives

• Name several general characteristics of storage systems. • Describe the three most common types of hard drives

and what they are used for today. • Discuss the various types of optical discs available today

and how they differ from each other. • Identify some flash memory storage devices and media

and explain how they are used today. • List at least three other types of storage systems. • Summarize the storage alternatives for a typical personal

computer.

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 2

Overview

• This chapter covers: – The characteristics common among all storage systems – The primary storage for most personal computers—the

hard drive – How optical discs work and the various types that are

available today – Flash memory storage systems – Network and cloud storage, smart cards, and the storage

systems used with large computer systems – Storage alternatives for a typical personal computer

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 3

Storage System Characteristics

• A storage system consists of a storage medium and a storage device – The storage medium is the hardware where data is stored

• DVD disc, flash memory card, etc. – The storage device is the hardware into which the storage

medium is inserted • DVD drive, flash memory card reader, etc. • Can be internal, external, or remote • Storage devices are typically identified by letter

– Some storage media is removable; some is not

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 4

Examples of Storage Device Identifiers

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 5

Volatility and Random vs. Sequential Access

• Volatility – Storage media are nonvolatile and, therefore, is used for

data to be saved for later use • Random vs. sequential access

– Random access (direct access) allows data to be retrieved from any location on the storage medium

• Virtually all storage devices use random access – Sequential access means that retrieval of data can occur

only in the order in which it was physically stored on the storage medium; for example, a magnetic tape drive

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 6

Files, Filenames, and Folders

• A file is anything stored on a storage medium, such as a program, document, digital image, or song

• A filename is a name given to a file by the user • A folder is a named place on a storage medium

into which files can be stored

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 7

Logical vs. Physical Representation and Types of Storage Technologies Used

• Logical file representation – Individuals view a document stored as one complete unit

in a particular folder on a particular drive • Physical file representation

– Computers access a particular document stored on a storage medium using its physical location or locations

• Types of storage technology – Magnetic (conventional hard drives) – Optical (optical discs) – Electrons (flash memory media)

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 8

Hard Drives

• A hard drive stores most programs and data for a personal computer – Can be internal or external – Available with built-in encryption that limits access to only

authorized users

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 9

Magnetic Hard Drives

• A magnetic hard drive or hard disk drive (HDD) contains particles on the metal disks inside the drive that are magnetized to represent the data’s 0s and 1s

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 10

Magnetic Hard Drives (cont’d)

• One or more metal hard disks are permanently sealed inside the drive along with an access mechanism and read/write heads

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 11

Hard Disk Organization

• Tracks are concentric paths on the disk where data is recorded

• Sectors are small pieces of a track • Clusters consist of one or more sectors

• Smallest addressable area of a disk • Cylinders are a collection of tracks located in the same

location on a set of hard disk surfaces

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 12

Examples of Tracks, Sectors, Clusters, and Cylinders

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 13

Magnetic Hard Drive Technologies

• Traditional: Longitudinal magnetic recording aligns magnetic particles on a hard disk horizontally, parallel to the hard disk’s surface

• Newer: Perpendicular magnetic recording (PMR) places bits upright and closer together to increase capacity and reliability

• Newest: Shingled magnetic recording (SMR) squeezes more data onto disks by overlapping the data tracks on them like the shingles on a roof

• Emerging: Heat-assisted magnetic recording (HAMR) uses lasers to temporarily heat the surface of the hard disks when storing data in order to store more data

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 14

How It Works

More Storage for Your Tablet • Tablets often have between

16 GB and 128 GB of storage • To extend storage, you can

transfer content to and from desktops or notebooks

• Easier to use a wireless hard drive and Wi-Fi – Download the

appropriate app The 2 TB Seagate Wireless Plus magnetic hard drive.

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 15

Inside the Industry

Data Recovery Experts • Recover data from damaged storage devices • Used when devices are physically damaged or just stop

working • It is important to back up data to prevent data loss

Data recovery. The data on this destroyed computer (left) was recovered by data recovery experts in a clean room (right).

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 16

Solid-State Drives (SSDs)

• A solid-state drive (SSD) uses flash memory technology to store data – Uses less power and has no

moving parts – Much faster than magnetic

hard drives, but more expensive

– The norm for netbooks, mobile devices, and other portable devices

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 17

Solid-State Hybrid Drives (SSHDs)

• A solid-state hybrid drive (SSHD) or hybrid drive uses a combination of magnetic disks and flash memory chips – The data that is most

directly associated with performance is stored in the flash memory

– Nearly as fast as solid-state drives (SSDs)

– Slightly more expensive than magnetic hard disk drives (HDDs)

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 18

Internal and External Hard Drives

• Internal hard drives are permanent storage devices located inside the system unit – Removed only if a problem develops

• External hard drives transport large amounts of data from one computer to another, for backup, and for additional storage – Full-sized external hard drives are often used for backup – Portable external hard drives: smaller and easier to

transport – Most connect with a USB connection, although some may

connect through wired or wireless networking connections © 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 19

Examples of External Hard Drives

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 20

Hard Drive Speed and Disk Caching

• Disk access time is the total time that it takes for a hard drive to read or write data • Consists of seek time, rotational delay, and data

movement time • SSDs don’t require seek time or rotational delays

• Disk cache consists of memory used in conjunction with a magnetic hard drive to improve system performance – Typically consists of RAM-based disk cache located inside

the hard drive case – Can speed up performance and save battery life

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 21

Hard Drive Partitioning

• Partitioning divides the physical capacity of a single drive logically into separate areas, called partitions – Each partition functions as an independent hard drive – Referred to as logical drives – Increases efficiency (smaller drives use smaller clusters)

• Partitions are used to create: – A recovery partition – A new logical drive

for data – A dual boot system

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 22

Hard Drive File Systems and Interface Standards

• File system determines the partition size, cluster size, maximum drive size, and maximum file size – FAT, FAT32, and NTFS

• Interface standards determine how a drive connects to the computer

• Common standards – Serial ATA (SATA): most common internal hard drive

interface standard – Serial attached SCSI (SAS) – Fibre Channel – Internet SCSI (iSCSI)

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 23

Quick Quiz (1)

1. Of the following three options, the storage media that would likely hold the most data is a(n) __________. a. HDD b. USB flash drive c. SSD

2. True or False: SSDs are subject to mechanical failures just like magnetic hard drives.

3. The circular rings on a magnetic disk on which data is stored are called __________.

Answers: 1) a; 2) False; 3) tracks Understanding Computers: Today and Tomorrow, 15th Edition 24

Optical Discs

• Optical discs are thin circular plastic discs – Are read from and written to using laser beams – Are commonly used for software delivery – Divided into sectors like magnetic discs but use a single

spiral track (groove) – Have a relatively large capacity and are durable – Used for backup purposes and for storing and transporting

music, photos, video, etc.

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 25

Representing Data on an Optical Disc

• Pits and lands are used to represent 1s and 0s • The transition between a pit and a land represents a 1;

no transition represents a 0 • Read-only optical disc

– Surface of disc is molded or stamped to represent data • Recordable or rewritable disc

– The reflectivity of the disc is changed using a laser beam to represent the data

– Different types of optical discs use different types of laser beams

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 26

How Recorded Optical Discs Work

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 27

Optical Drives

• Optical discs are read by optical drives – The optical drive must support the type

of optical disc being used – Almost always backward-compatible – Recording data onto a optical disc is

called burning; requires burning software – Optical drives can be internal or external

• External drives typically connect via USB port

• External drives can be used with netbooks and other devices without an optical drive

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 28

Optical Disc Shapes, Sizes, and Capacities

• Standard size is 120-mm (about 4.7 inches) – Mini discs are smaller (about 3 inches)

• Theoretically can be made into various shapes, but patent battle has resulted in custom shapes not being available

• Clear background is sometimes used to make a disc look custom shaped

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 29

Advantage of Optical Discs

• Major advantage: Large capacity – CD discs are normally single layer and hold 700 MB – DVD discs hold 4.7 GB (single-layer) or 8.5 GB (dual-layer) – BD discs hold 25 GB (single-layer) or 50 GB (dual-layer) – BDXL standard uses even more layers to boost capacity up

to 128 GB – Newest BD discs are Ultra HD Blu-ray discs that hold up to

100 GB and are designed to deliver Ultra HD (4K) movies – Discs can also be double-sided

• Read on one side at a time; must be turned over to access the second side

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 30

Summary of Optical Discs

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 31

Read-Only Optical Discs: CD-ROM, DVD-ROM, and BD-ROM Discs

• CD-ROM, DVD-ROM, and BD-ROM discs can be written to, but not erased and reused – Pits are permanent – CD-ROM and DVD-ROM discs come prerecorded with

software, music, movies, etc. – BD-ROM discs come prerecorded with movies

• Ultra HD Blu-ray discs can be used for 4K movies – Additional proprietary read-only discs

• Gaming systems like Wii, Xbox, PlayStation, etc.

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 32

Recordable Optical Discs: CD-R, DVD-R, DVD+R, and BD-R Discs

• CD-R, DVD-R, DVD+R, and BD-R discs can be written to, but cannot be erased and reused – Pits are created in the disc when the disc is recorded – Most discs have a recording layer containing organic light-

sensitive dye between disc’s plastic and reflective layers • BD-R discs use inorganic material instead

– DVD-R DL and DVD+R DL are dual-layer discs – BD-R DL discs are dual-layer discs; BD-R XL use 3 or 4 layers – Used for backing up files, sending large files to others, and

storing multimedia files

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 33

Rewritable Optical Discs: CD-RW, DVD- RW, DVD+RW, and BD-RE Discs

• CD-RW, DVD-RW, DVD+RW, and BD-RE discs can be written to, erased, and overwritten just like magnetic hard disks – Uses phase change technology

• Heating and cooling process is used to change the reflectivity of the disc

– The capacities are the same as their read-only and recordable counterparts

– Appropriate for transferring large files from one computer to another or otherwise temporarily storing data (disc can be reused)

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 34

Trend

Ultra HD (4K) • Is the next big step in high-definition

(HD) TVs and content • Four times the resolution of ordinary HD • Requires four times as much data as

regular HD video • Many Internet connections are not fast

enough to support the large amounts of data required for 4K quality

• Available for those individuals who have the speed and bandwidth to support it; also available on Ultra HD discs

An example of a 4K movie.

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 35

Quick Quiz (2)

1. The capacity of the standard DVD disc is _____. a. 50 GB b. 650 MB c. 4.7 GB

2. True or False: A DVD-RW disc can be written to and rewritten to.

3. The tiny depressions, dark areas, or otherwise altered spots on an optical disc that are used to represent data are called __________.

Answers: 1) c; 2) True; 3) pits

Understanding Computers: Today and Tomorrow, 15th Edition 36

Flash Memory Storage Systems

• Flash memory is a chip-based storage medium that represents data using electrons – Used in a variety of storage systems

• Embedded flash memory refers to flash memory chips embedded into products – Smartphones, tablets, smart watches, and even sunglasses

and wristwatches – Usually the primary storage for mobile devices such as

tablets and smartphones

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 37

Examples of Embedded Flash Memory

38© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

This tablet contains 64 GB of embedded flash memory.

An embedded flash memory chip.

Flash Memory Cards and Readers

• A flash memory card is a small card containing one or more flash memory chips, a controller chip, and metal contacts to connect the card to the device or reader being used – Available in a variety of formats; these formats are not

interchangeable – Secure Digital (SD) is one of the most widely used types of flash

memory media – Most common type of storage media for digital cameras,

smartphones, and other portable devices • Many devices today have a built-in flash memory card reader;

an external reader via USB port is also used • Adapters allow the use of smaller flash memory cards in a

larger slot of the same type (microSD to SD, etc.)

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 39

Examples of Flash Memory Cards, Readers, and Adapters

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 40

Flash Memory Cards

• General-purpose flash memory card – Appropriate for most

applications • Specialized flash memory cards

– Professional flash memory cards

– Gaming flash memory cards – Encrypted flash memory cards

• Project Vault is a computer on a flash memory card

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 41

USB Flash Drives

• USB flash drives (USB drives or flash drives) consist of flash memory media integrated into a self-contained unit that plugs into and is powered by a USB port – Designed to be very small and very portable – Available in a host of formats

• Low-profile drives, custom shapes, micro drives, etc. – Can be built into a consumer product – Additional related hardware becoming available

• USB duplicator systems

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 42

Examples of USB Flash Drives

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 43

Technology and You

Tiny PCs • The size of a USB flash drive • Typically connect to a TV via an

HDMI port • May also have built-in storage and

a microSD • Capabilities vary; smart TVs can

display and stream Internet content

• The newest tiny PCs are fully functioning “computers-on-a- stick”

Intel Compute Stick

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 44

Quick Quiz (3)

1. Flash memory cards are available today in capacities up to _____. a. 64 GB b. 512 MB c. 1 TB

2. True or False: Flash memory is the primary storage for mobile devices such as tablets and smartphones.

3. The most common type of flash memory card today is the __________ card.

Answers: 1) c; 2) True; 3) SD Understanding Computers: Today and Tomorrow, 15th Edition 45

Other Types of Storage Systems

• Remote storage refers to using a storage device that is not connected directly to the user’s computer

• Network storage: Using a storage device via a local network – Works in much the same way as using local storage – Network attached storage (NAS) devices are high

performance storage systems connected individually to a network

– A storage area network (SAN) consist of separate network of hard drives or other storage devices that are attached to the main network

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 46

Examples of Network Storage

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 47

Cloud Storage

• Cloud storage (online storage) is accessed via the Internet – Cloud applications (Flickr, Facebook, Google Docs, etc.) – Online storage sites (Box, Dropbox, OneDrive, etc.) – Growing in importance because more and more

applications are Web-based – Increasingly used for backup purposes – Files can be synched between PC and cloud storage – Many online storage sites offer some free storage – Business cloud storage is available; businesses can also

create private clouds © 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 48

Example of Cloud Storage

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 49

Smart Cards

• A smart card is a credit card-sized piece of plastic that contains some computer circuitry (processor, memory, and storage) – Stores a small amount of data (about 64 KB or less) – Commonly used to store prepaid amounts of digital cash or

personal information – Smart card readers are built into or attached to a

computer, door lock, vending machine, or other device – Some smart cards store biometric data – Use of mobile smart cards is an emerging trend

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 50

Examples of Uses for Smart Cards

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 51

Storage Systems for Large Computer Systems

• Business storage needs are growing exponentially – Digital data produced is expected to double every two

years through 2020 • A storage server contains multiple high-speed hard drives

– Larger than typical NASs – Usually contain drawers of hard drives – Typically use fast Fibre Channel or iSCSI connections – Scalable so that more hard drives can be added as needed – Can use magnetic and/or SSD drives

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 52

Example of a Large Storage Systems

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 53

RAID

• RAID (redundant arrays of independent discs) is a method of storing data on two or more hard drives that work together to record redundant copies – Used to protect critical data on large storage systems – Helps to increase fault tolerance – Different levels of RAID:

• RAID 0 = disk striping (spread files over two or more hard drives)

• RAID 1 = disk mirroring (duplicate copy) • Other levels use a combination or striping and mirror

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 54

Two Primary RAID Techniques

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 55

Newer RAID Systems

• New storage systems are easier to set up and maintain so dedicated RAID personnel are not needed – For example, the Drobo system:

• Connects to a computer or a network via a USB cable • Contains drive bays into which hard drives can be

inserted • Has capacity and status indicators – drives can be

inserted and removed as needed

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 56

Archival Storage Systems

• Data archiving is the process of identifying and moving data that is no longer actively being used from regular storage systems to a separate long-term archival storage system

• Options for data archival systems: – Large hard drives, such as a helium hard drive (10 TB) – Magnetic tape

• Typically cartridge tapes; can be tape libraries – Higher capacity, archival Blu-ray Discs that are becoming

available; so are optical jukeboxes – Cloud storage

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 57

Examples of Data Archiving Options

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 58

Evaluating Your Storage Alternatives

• Product characteristics to consider: – Speed, compatibility, storage capacity, convenience, and

portability • Each storage alternative normally involves trade-offs • Research which devices and media are most appropriate

to your personal devices • All computers need at least one convenient USB port • Mobile device users

– Fewer options for storage alternatives – Require appropriate wireless connectivity

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 59

Quick Quiz (4)

1. An online photo sharing site is an example of __________. a. RAID b. cloud storage c. holographic storage

2. True or False: Smart cards today typically hold at least 1.44 MB of data.

3. A type of sequential storage that is sometimes used today for business data archiving and in some backup systems because of its low cost per terabyte is __________.

Answers: 1) b; 2) False; 3) magnetic tape Understanding Computers: Today and Tomorrow, 15th Edition 60

Summary

• Storage Systems Characteristics • Hard drives • Optical Discs And Drives • Flash Memory Storage Systems • Other Types of Storage Systems • Evaluating Your Storage Alternatives

© 2017 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use. 61