Data Can Be Stored Short or Long Term

Short term storage is in RAM

RAM is Random Access Memory

When the power goes off data in RAM is lost!

This means we require other memory types for permanent storage.

Permanent Storage is also generally cheaper than RAM.

This means we can store more in Permanent Memory!

Hard Diskettes or Hard Drive

Current Hard Drives use magnetic technology and have capacities of Hundreds of Gigabytes or more for less than $200.

Most Hard Drives for PC’s are EIDE, or Ultra2 EIDE’s.

Also USB and Firewire Drives are available…removable!

PCMCIA for laptops…pricey

HD Controllers

Most of the intelligence for the HD is on the Onboard Controller

Some computers use SCSI hard drives and other SCSI devices

RAID is a special type of redundant hard drive setup with multiple disks.

High Capacity Removable Disk Storage

Used to shuttle large amounts of data between computers

Can also be used as a backup media

Capacities range from 35M to over 2G

Cost of media varies depending on technology used

Common PC Removable Media Types

SyQuest drives (over 1G data)

Uses proprietary 3.5 and 5.25 inch cartridges

Jaz drives (up to 2G data)

Media rather pricey

Tape drives (Over 25G data)

De facto standard for backing up data (covered in detail later)

Types of Removable Media Drives

Magnetic Media

Zip Drive

LS-120 Drive

Optical Media (Magneto-Optical)

CD-ROM

CD/RW

DVD

DVD/RW can be DVD+,-, or DL (double layer

Zip Drive

Available as IDE, SCSI, USB or Parallel interfaces

Stores up to 250 megs of data

Proprietary standard

Up to 1M/sec access time

LS-120 Drive

Also known as “Super Disk”

Can read and write to standard 1.44M floppy disks

Can store up to 83 times (120 Megs) as much data as 1.44M floppy

Uses IDE, Parallel or USB interfaces

What is a CD-ROM?

5 inch disk

Holds up to 682Megs of data

Up to 74 minutes of audio

Are coated with aluminum

Most popular media used for software distribution

Optical storage media

CD-ROM Technology

Data is written by etching pits into the surface of the disk

Areas that are not pitted are called “lands”

Light is beamed to the disk

The reflection is interpreted by the processors as either data or sound

Performance Factors

Drive speeds up to 100x (100 times faster than a standard audio CD)

Rated drive speeds are actually maximum speeds

Up to 21Mb/sec transfer rates

Access rates up to 80ms

CD-ROM Drive Interfaces

SCSI

Best performance and flexibility

IDE/ATAPI

Most common interface. Good performance at a lower cost

Parallel port

Convenient and easy to install. Can be expensive

PCMCIA/USB for Laptops

Writable CD-ROM Drives

CD-R

WORM (Write Once Read Many) drives

Excellent for burning “Masters” of data or music

CD-RW

Can be rewritten at least one thousand times

DVD (Digital Versatile Disk)

DVD-Video contains only video programs

DVD-ROM used as a data storage medium for PCs

Backwards compatible (will play CD-ROM and audio CDs)

DVD Specifications

Single sided single layer holds up to 4.7G data

Single sided dual-layer up to 8.5G data

Double sided single layer up to 9.4G

Double sided dual-layer up to 17G

2 New Technologies, Blue and HD DVD released in 2006

Other CD Technologies

Enhanced Music CDs

Contains music and data. Sometimes called CD Plus or CD Extra

PhotoCD

Sold by Kodak as a photo archiving media

Divx

Short lived technology, already obsolete

Flash and Other New Storage

Flash memory cards used in new technologies such as digital cameras and mp3 players

Several Different types in use, no current standard

Other methods on the horizon including molecular technology

Safeguarding Data-Backup

Data The most expensive component on a business PC!

Loss of Data can be a disaster!

Backup means making an extra copy.

Tape, duplicate Hard drives, or other means.

Separate the back up physically!

Tornadoes, Hurricanes, Floods, Fire & Theft!

Tape Storage

Popular in past with larger computers due to lower cost

Sequential and slow used primarily as backup.

Larger computers use larger tapes

PC’s generally use smaller cartridges which are cheaper, but generally slower

Tape is plastic with iron rust bonded on

Disk Drives

First disk drives were 8 inches, then 5 ¼ inch in diameter

Current Floppies are 3 ½ inch in diameter

They hold 1.44 Megabytes of Data

Zip diskettes hold 100 or 250 megabytes

Super disks hold 100 megabytes and can read the old 3 ½ inch 1.44 Meg floppies.

Disk Characteristics

Diskettes, both floppy and hard must be formatted before use.

They consist of

Tracks (a circular path around) and

Sectors

Hard disks have more tracks and sectors and are much faster.

Some devices are much faster than others as noted by Seek time or data transfer rates.

Optical Technologies

Since the invention and widespread use of the Laser, light can be used to read stored data.

CD ROMS were the first optical devices used widely to store data. Stores 650 Megs

Uses pits to store data.. No reflection there.

DVD ROMS, and CD R and RW now in use

DVD can store up to 4.7-17 GIG’s of data

New Storage

Flash memory cards used in new technologies such as digital cameras

Other methods on the horizon!!!


	Short term storage is in RAM
	RAM is Random Access Memory
	When the power goes off data in RAM is lost!
	This means we require other memory types for permanent storage.
	Permanent Storage is also generally cheaper than RAM.
	This means we can store more in Permanent Memory!


	Current Hard Drives use magnetic technology and have capacities of Hundreds of Gigabytes or more for less than $200.
	Most Hard Drives for PC’s are EIDE, or Ultra2 EIDE’s.
	Also USB and Firewire Drives are available…removable!
	PCMCIA for laptops…pricey


	Most of the intelligence for the HD is on the Onboard Controller
	Some computers use SCSI hard drives and other SCSI devices
	RAID is a special type of redundant hard drive setup with multiple disks.


	Used to shuttle large amounts of data between computers
	Can also be used as a backup media
	Capacities range from 35M to over 2G
	Cost of media varies depending on technology used


	SyQuest drives (over 1G data)
		Uses proprietary 3.5 and 5.25 inch cartridges
	Jaz drives (up to 2G data)
		Media rather pricey
	Tape drives (Over 25G data)
		De facto standard for backing up data (covered in detail later)


	Magnetic Media
		Zip Drive
		LS-120 Drive
	Optical Media (Magneto-Optical)
		CD-ROM
		CD/RW
		DVD
		DVD/RW can be DVD+,-, or DL (double layer


	Available as IDE, SCSI, USB or Parallel interfaces
	Stores up to 250 megs of data
	Proprietary standard
	Up to 1M/sec access time


	Also known as “Super Disk”
	Can read and write to standard 1.44M floppy disks
	Can store up to 83 times (120 Megs) as much data as 1.44M floppy
	Uses IDE, Parallel or USB interfaces


	5 inch disk
	Holds up to 682Megs of data
	Up to 74 minutes of audio
	Are coated with aluminum
	Most popular media used for software distribution
	Optical storage media


	Data is written by etching pits into the surface of the disk
	Areas that are not pitted are called “lands”
	Light is beamed to the disk
	The reflection is interpreted by the processors as either data or sound


	Drive speeds up to 100x (100 times faster than a standard audio CD)
	Rated drive speeds are actually maximum speeds
	Up to 21Mb/sec transfer rates
	Access rates up to 80ms


	SCSI
		Best performance and flexibility
	IDE/ATAPI
		Most common interface. Good performance at a lower cost
	Parallel port
		Convenient and easy to install. Can be expensive
	PCMCIA/USB for Laptops


	CD-R
		WORM (Write Once Read Many) drives
		Excellent for burning “Masters” of data or music
	CD-RW
		Can be rewritten at least one thousand times


	DVD-Video contains only video programs
	DVD-ROM used as a data storage medium for PCs
	Backwards compatible (will play CD-ROM and audio CDs)


	Single sided single layer holds up to 4.7G data
	Single sided dual-layer up to 8.5G data
	Double sided single layer up to 9.4G
	Double sided dual-layer up to 17G
	2 New Technologies, Blue and HD DVD released in 2006


		Enhanced Music CDs
			Contains music and data. Sometimes called CD Plus or CD Extra
		PhotoCD
			Sold by Kodak as a photo archiving media
		Divx
			Short lived technology, already obsolete


	Flash memory cards used in new technologies such as digital cameras and mp3 players
		Several Different types in use, no current standard
	Other methods on the horizon including molecular technology


	Data The most expensive component on a business PC!
	Loss of Data can be a disaster!
	Backup means making an extra copy.
	Tape, duplicate Hard drives, or other means.
	Separate the back up physically!
	Tornadoes, Hurricanes, Floods, Fire & Theft!


	Popular in past with larger computers due to lower cost
	Sequential and slow used primarily as backup.
	Larger computers use larger tapes
	PC’s generally use smaller cartridges which are cheaper, but generally slower
	Tape is plastic with iron rust bonded on


	First disk drives were 8 inches, then 5 ¼ inch in diameter
	Current Floppies are 3 ½ inch in diameter
	They hold 1.44 Megabytes of Data
	Zip diskettes hold 100 or 250 megabytes
	Super disks hold 100 megabytes and can read the old 3 ½ inch 1.44 Meg floppies.


	Diskettes, both floppy and hard must be formatted before use.
	They consist of
		Tracks (a circular path around) and
		Sectors
		Hard disks have more tracks and sectors and are much faster.
		Some devices are much faster than others as noted by Seek time or data transfer rates.


	Since the invention and widespread use of the Laser, light can be used to read stored data.
	CD ROMS were the first optical devices used widely to store data. Stores 650 Megs
	Uses pits to store data.. No reflection there.
	DVD ROMS, and CD R and RW now in use
		DVD can store up to 4.7-17 GIG’s of data


	Flash memory cards used in new technologies such as digital cameras
	Other methods on the horizon!!!