chapter 5 - storage peripherals

Aris Haryanto, S.Kom, MM Pengantar Teknologi Informasi

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Chapter 5

Understanding Storage Peripherals


Pada akhir pertemuan ini, diharapkan mahasiswa

akan mampu :

menjelaskan tentang contoh-contoh perangkat media penyimpanan pada

komputer

Learning Outcomes

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Magnetic Storage

Optical Disc

Cloud Storage

Flash Memory

Enterprise Storage

Outline Materi

3


What is storage?

A storage medium is the physical material on which a computer keeps data,

information, programs, and applications

Storage

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Cloud storage is another storage option, in which the actual online storage media

used is transparent to the user


Storage

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Storage

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

from storage media Reading is the process of transferring items from a storage medium into memory

Writing is the process of transferring items from memory to a storage medium


Storage

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Capacity is the number of bytes a storage medium can hold


Storage Medium

(floppy disks, Zip disks,

hard disks, flash memory,CDs)

How does volatility compare?

No

nvo

lati

le

Storage medium is nonvolatilecontents retained when power is off

Contents

retained

Contents

available to user

Memory

(most RAM)

(chips on motherboard)

Screen Display

ON OFF

Vo

lati

le

Display

disappears

Data and

instructions

available to user

Display

appears

Data and

instructions erased

Memory is volatileholds data and instructions temporarily

Storage

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Writing

Process of transferring

items from memory

to storage media

What is a storage device?

Reading

Process of transferring

items from storage

media to memory

Hardware that

records and

retrieves items

to and from

storage media

Functions as source

of input Creates output

Storage

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What is access time?

Storage

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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


What is a floppy disk? Portable, inexpensive storage

medium (also called diskette)

Thin, circular, flexible film enclosed

in 3.5 wide plastic shell

shutter

shell

liner

magnetic coating

flexible thin film

metal hub

Floppy Disks

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Hard Disks

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A hard disk contains one or more inflexible, circular platters that use magnetic particles to store data,

instructions, and information


How does a hard disk work?

Step 1. Circuit board controls

movement of head actuator

and a small motor.

Step 2. Small motor spins

platters while

computer is running.

Step 3. When software requests a

disk access, read/write

heads determine current

or new location of data.

Step 4. Head actuator positions

read/write head arms over

correct location on platters

to read or write data.

Hard Disks

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Hard Disks

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Hard disks can store data using

longitudinal

recording or

perpendicular

recording


Hard Disks

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Characteristics of a hard disk include:

Capacity Platters Read/Write

Heads

Cylinders Sectors

and Tracks Revolutions per Minute

Transfer Rate

Access Time


Hard Disks

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The hard disk arms move the

read/write head,

which reads items

and writes items in

the drive

Location often is referred to by its

cylinder


Hard Disks

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A head crash occurs when a read/write head touches the surface of a platter

Always keep a backup of your hard disk


Hard Disks

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An external hard disk is a separate free-standing hard disk that connects to your computer with a cable or wirelessly

A removable hard disk is a hard disk that you insert and remove from a drive

Internal and external hard disks are available in miniature sizes (pocket hard drive)


Hard Disks

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A disk controller consists of a special-purpose chip and electronic circuits that control the transfer of

data, instructions, and information from a disk to and

from the system bus and other components of the

computer

SATA EIDE

SCSI SAS


Flash Memory Storage

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Flash memory chips are a type of solid state media and contain no moving parts

Solid state drives (SSDs) have several advantages over magnetic hard disks:

Faster access time Faster transfer rates Generate less heat and consume less

power Last longer



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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

CompactFlash (CF)

Secure Digital (SD)

Secure Digital High Capacity

(SDHC) microSD

microSDHC xD Picture

Card Memory Stick

Memory Stick Micro (M2)



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USB flash drives plug into a USB port on a computer or mobile device


Cloud Storage

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Cloud storage is an Internet service that provides storage to computer or mobile

device users


Cloud Storage

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Optical Discs

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An optical disc consists of a flat, round, portable disc made of metal, plastic, and

lacquer that is written and read by a laser

Typically store software, data, digital photos, movies, and music

Read only vs. rewritable


How does a laser read data on a CD or DVD?

laser

diode

laser

diode

prism prism

light- sensing diode

light- sensing diode

0 1

lens lens pit land

disc label

Step 1. Laser diode

shines a light

beam toward

disc.

Step 2. If light strikes

a pit, it scatters.

If light strikes a

land, it is

reflected back

toward diode.

Step 3. Reflected light is

deflected to a

light-sensing diode,

which sends digital

signals of 1 to

computer. Absence

of reflected light is

read as digital

signal of 0.

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Optical Discs

Aris Haryanto, S.Kom, MM Pengantar Teknologi Informasi 29

Optical Discs


Optical Discs

Optical discs 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


Optical Discs

A CD-ROM can be read from but not written to

Read from a CD-ROM drive or CD-ROM player

A CD-R is a multisession optical disc on which users can write, but not erase

A CD-RW is an erasable multisession disc

Must have a CD-RW drive


Optical Discs

A DVD-ROM is a high-capacity optical disc on which users can read but not write or erase

Requires a DVD-ROM drive

A Blu-ray Disc-ROM (BD-ROM) has a storage capacity of 100 GB

DVD-RW, DVD+RW, and DVD+RAM are high-capacity rewritable DVD formats


Optical Discs


How should you care for Optical Discs?

Do store the disc in a jewel box when not in use

Do hold a disc by its edges

Do not eat, smoke, or drink near a disc

Do not stack discs

Do not expose the disc to excessive heat or sunlight

Do not touch the underside of the disc

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Optical Discs


Enterprise Storage

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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


Enterprise Storage

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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


Enterprise Storage

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A storage area network (SAN) is a high-speed network with the sole purpose of

providing storage to other attached servers


What is tape?

Magnetically coated plastic ribbon capable of storing large

amounts of data at low cost

Primarily used for backup

Other Types of Storage

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A tape drive reads and writes data and information

on a tape



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A magnetic stripe card contains a

magnetic stripe that

stores information

A smart card stores data on a thin

microprocessor

embedded in the

card



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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



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Microfilm and microfiche store microscopic images of documents on a roll or sheet film


Source : Shelly, Gary B. Discovering Computers (2004/2005/2006). Thomson

Course Technology. PPT for Chapter 7.

chapter 5 - storage peripherals

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