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Introduction to Computers

Introduction to ITLecture 5

Hard Disk DriveFlash MemoryCould Storage

.This lecture and its associated materials have been produced by Dr. Weerachai Anotaipaiboon of iAcademy for the purposes of lecturing on the above described subject and the material should be viewed in this context. Unless otherwise stated, all pictures used in the lectures are taken from Discovering Computers by Gary B. Shelly and Misty E. Vermaat. The work does not constitute professional advice and no warranties are made regarding the information presented. The Author and iAcademy do not accept any liability for the consequences of any action taken as a result of the work or any recommendations made or inferred. Permission to use any of these materials must be first granted by iAcademy.

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Agenda• Week 4 Review• Week 5 Lecture Coverage– HDD.– Flash Memory.– Could Storage.

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Lecture 4 Review1. What Are the Four Types of Output?2. What Are the Characteristics of Various Display

Devices?3. What Factors Affect the Quality of an LCD

monitor or LCD screen?

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Lecture 4 Review4. What Are the Various Ways to Print?5. How Is a Nonimpact Printer Different from an

Impact Printer?6. What Are the Uses and Characteristics of

Speakers, Headphones, and Earbuds?7. What Output Options Are Available for

Physically Challenged Users?

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Objectives Overview1. Differentiate between storage devices and

storage media2. Describe the characteristics of an internal hard

disk including capacity, platters, read/write heads, cylinders, sectors and tracks, revolutions per minute, transfer rate, and access time

3. Discuss the purpose of network attached storage devices, external and removable hard disks, and hard disk controllers

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Objectives Overview4. Describe the various types of flash memory

storage: solid state drives, memory cards, USB flash drives, and ExpressCard modules

5. Describe cloud storage and explain its advantages

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Storage

Storage holds data, instructions, and information for future use

A storage medium or secondary storage is the physical material on which a computer keeps data, instructions, and information

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Storage

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Storage

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

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Storage

• 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 (source of input)

Writing is the process of transferring items from memory to a storage medium (creating output)

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Storage

• 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 (also called transfer rate)

• Memory access time – nanoseconds

• Storage access time - milliseconds

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Hard Disks

• A hard disk (or hard disk drive) contains one or more inflexible, circular platters that use magnetic particles to store data, instructions, and information– Fixed disk– Portable

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Hard Disks

• Hard disks can store data using longitudinal recording or perpendicular recording

• Perpendicular recording can provide storage capacities about 10 times greater than longitudinal recording

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Hard Disks

• Characteristics of a hard disk include:

Capacity Platters Read/Write Heads

Cylinders Sectors and Tracks

Cluster or allocation unit

(group of sectors)

Revolutions per Minute (5400-

15000 rpm)

Transfer Rate (15 – 320

MBps)

Access Time (3 – 12 ms)

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Hard Disks

• Formatting is the process of dividing the disk into tracks and sectors so that the operating system can store and locate data and information on the disk

• form factor– Term that refers to the size of platters in a hard disk.

• 3.5 inches• 2.5 inches

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Hard Disks

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Hard Disks

• https://www.youtube.com/watch?v=kdmLvl1n82U

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Hard Disks

• 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

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Hard Disks

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

• Always keep a backup of your hard disk

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Hard Disks

• disk cache– Memory chips on a hard disk that store frequently

accessed items such as data, instructions, and information. Also called a buffer.

– Improve access time– Work similar to memory cache– 2 MB – 32 MB

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Hard Disks

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Hard Disks

• RAID (redundant array of independent disks) is a group of two or more integrated hard disks– Connect multiple smaller disks into a single unit

• A network attached storage (NAS) device is a server connected to a network with the sole purpose of providing storage– Often use RAID

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Hard Disks

• https://www.youtube.com/watch?v=PP0iQs8qBNU

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Hard Disks

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 (miniature hard disks) 1.8, 1, 0.85 inch

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Hard Disks

• 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– Part of hard disk– On motherboard– Separate adapter SATA EIDE

SCSI SAS

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Hard Disks

• SATA (Serial Advanced Technology Attachment)– Hard disk interface that uses serial signals to transfer data, instructions, and information and has

transfer rates of up to 300 MBps and higher.– Cables are thinner, longer, more flexible and less susceptible to interference than cable that uses

parallel signals.– eSATA: Acronym for external SATA; hard disk interface that is much faster than USB and FireWire.

• EIDE (Enhanced Integrated Drive Electronics)– Interface that uses parallel signals to transfer data, instructions, and information and can support

up to four hard disks at 137 GB per disk.– Data transfer rates up to 133 MBps

• SCSI (Small Computer System Interface)– Type of high-speed parallel interface used to attach peripheral devices to a computer.– Data transfer rates up to 640 MBps

• SAS (serial-attached SCSI)– Newer type of SCSI that uses serial signals to transfer data, instructions, and information.– Data transfer rates up to 750 MBps

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Flash Memory Storage

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

• Solid state drive (SSDs) is a storage device that typically uses flash memory to store data, instructions, and information.– Form factors: 3.5, 2.5, 1.8 inches– Capacities: 16 – 256 GB and more– have several advantages over magnetic hard disks:

Faster access timeAbout 0.1 ms (80

times faster)

Faster transfer rates

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Flash Memory Storage

• https://www.youtube.com/watch?v=MchPfwtYIXc

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Flash Memory Storage

• 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

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Flash Memory Storage

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Flash Memory Storage

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Flash Memory Storage

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Flash Memory Storage

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Flash Memory Storage

• USB flash drives (sometimes called a thumb drive, handy drive) plug into a USB port on a computer or mobile device

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Flash Memory Storage

• An ExpressCard module is a removable device that fits in an ExpressCard slot

• Commonly used in notebook computers

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Cloud Storage

• Cloud storage is an Internet service that provides storage to computer users

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Cloud Storage

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Cloud Storage

• Users subscribe to cloud storage for a variety of reasons:

Access files from any computer

Store large files instantaneously

Allow others to access their files

View time-critical data and images immediately

Store offsite backups

Provide data center functions

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Cloud Storage

• https://www.youtube.com/watch?v=OFb0NaeRmdg

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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

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

• Read only vs. rewritable• 4.75 inches in diameter– Mini disc – 3 inches or less

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Optical Discs

• Optical disc store items by using microscopic pits and lands• High-powered laser light creates the pits• Low-powered laser light reads item from the disc.

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Optical Discs

• https://www.youtube.com/watch?v=YF0Si5JNH9E

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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

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Care of optical discs

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Optical Discs

• Speed of CD-ROM drive determines how fast it installs programs and access the disc.– Original CD-ROM drives were single-speed drives with transfer

rates of 150 KBps– Manufacturers measure all optical disc drives relative to this

original transfer rate of 150 KBps• For example, a 48x CD-ROM drive has a data transfer rate of 7,200

(48x150) KBps or 7.2 MBps

– CD-RW drives have 3 speeds: write/rewrite/read• For example, 52/32/52

– The process of writing on optical disc is called burning– The process of copying disc is called ripping

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Other Types of Storage

TapeMagnetic stripe cards and smart

cards

Microfilm and microfiche

Enterprise storage

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Other Types of Storage

• Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information

• A tape drive reads and writes data and information on a tape

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Other Types of Storage

• https://www.youtube.com/watch?v=QavarOBke0w

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Other Types of Storage

• 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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Other Types of Storage

• Microfilm and microfiche store microscopic images of documents on a roll or sheet film– Microfilm is a 100- to 215-foot roll of film– Microfiche is a small sheet of film, usually about 4x6

inches

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Other Types of Storage

• https://www.youtube.com/watch?v=hBKb2CHcKYU

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Other Types of Storage

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Other Types of Storage

• Enterprise storage stores huge volumes of data and information for large businesses– Uses special hardware for heavy use, maximum

availability, and maximum efficiency

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Any Questions?

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