Storage DevicesStorage Devices

By Artiom Nistrean, Jimmy AkyBy Artiom Nistrean, Jimmy Akyüüz.z.Not forgetting Daniel BrownNot forgetting Daniel Brown

IntroductionIntroduction

With out a storage devices you can not save anything With out a storage devices you can not save anything and all your hard work will be for NOTHING!and all your hard work will be for NOTHING!

There is a different storage device for different tasks. There is a different storage device for different tasks. Such as:Such as:

floppy diskfloppy disk USB sticksUSB sticks CDsCDs DVDsDVDs Hard DiskHard Disk Ram and ROMRam and ROM

Storage capacityStorage capacity

Data can be stored either in the 'internal memory' or on a 'storage Data can be stored either in the 'internal memory' or on a 'storage device'.device'.

The amount of data and instructions that can be stored is The amount of data and instructions that can be stored is measured in 'bytes'.measured in 'bytes'.

One byte contains 8 bits One byte contains 8 bits This is the smallest unit of data that can be stored. This is the smallest unit of data that can be stored. Each bit is represented as a binary number.Each bit is represented as a binary number.

Quantity Information

Bit Smallest unit of data

Byte 8 bits

Kilobyte(KB) Assumed to be 1,000 bytes. but its really 1,024bytes

Megabyte(MB) 1,000 KB (1,024 KB)

Gigabyte(GB) 1,000 GB (1,024 MB

Digital Versatile DisksDigital Versatile Disks

AdvantagesAdvantages Very large storage capacityVery large storage capacity Sound picture quality is excellent Sound picture quality is excellent

making it used mainly for video making it used mainly for video and sound storage.and sound storage.

Relatively cheap. Relatively cheap. DVD players can read CDs.DVD players can read CDs.

DisadvantagesDisadvantages DVDs do not work in CD drivesDVDs do not work in CD drives There is no single standard of There is no single standard of

DVD. DVD. Easily damaged.Easily damaged.

•A DVD is similar to a CD•It is one of the most common uses of copying and backing up data.•You can store up to 4.7GB of data on one side. Usually there is only one side to a DVD

Compact Disks (CDs)Compact Disks (CDs)

There are 3 main types of CDs:There are 3 main types of CDs:1.1. CD ROM (Read Only Memory) E.g. when you buy a CD you can only CD ROM (Read Only Memory) E.g. when you buy a CD you can only

read what’s on it.read what’s on it.2.2. CD worm this type of CD can mean you can burn data or memory on to CD worm this type of CD can mean you can burn data or memory on to

the disk only once but can read it many times.the disk only once but can read it many times.3.3. Cd-rw you can save data as many times as you want. e.g. rewritable. Cd-rw you can save data as many times as you want. e.g. rewritable.

Such as a floppy disk which is like a portable hard drive.`Such as a floppy disk which is like a portable hard drive.`4.4. A CD can store about 650mb. A CD can store about 650mb.

AdvantagesAdvantages Small, Small, portable, and cheap.portable, and cheap. Most computers can read CDs Most computers can read CDs Fast access to data stored on the disc Fast access to data stored on the disc

DisadvantagesDisadvantages Very fragileVery fragile Smaller memory capacity than a Smaller memory capacity than a

hard drive or DVDhard drive or DVD Slower to access than a hard drive Slower to access than a hard drive

Read only Memory (ROM)Read only Memory (ROM) Rom is a special kind of memory. It stores Rom is a special kind of memory. It stores

the BIOS (basic input output system)the BIOS (basic input output system) It allows you to check the amount of ram It allows you to check the amount of ram

installed, the type of CPU and the type of installed, the type of CPU and the type of hard disk, ect.hard disk, ect.

Can only be read by user.Can only be read by user. Data is stored permanently which is called Data is stored permanently which is called

non volatile memory.non volatile memory. ROM chip is attached to motherboardROM chip is attached to motherboard

Random access memory Random access memory (RAM)(RAM)

RAM is volatile memory which means it is temporary.RAM is volatile memory which means it is temporary. Most computers are sold with 1-2GB of RAM.Most computers are sold with 1-2GB of RAM. RAM stores modules need to make application work. RAM stores modules need to make application work.

e.g. opening a program may take time.e.g. opening a program may take time. RAM is needed to have multiple windows and RAM is needed to have multiple windows and

applications open.applications open. However if you open too many applications and However if you open too many applications and

windows the system will slow down and even crash, windows the system will slow down and even crash, this is because you ram is full so it has to decide which this is because you ram is full so it has to decide which memory is temporarily saved and what can be realized. memory is temporarily saved and what can be realized.

Hard DiskHard Disk

The hard disk is the main storage device The hard disk is the main storage device in you computer.in you computer.

All of you data files are stored on there.All of you data files are stored on there. A typical Hard disk stores 120GB- 1 A typical Hard disk stores 120GB- 1

TerabyteTerabyte It is possible to have an external hard It is possible to have an external hard

drive plugged into your computer through drive plugged into your computer through an USB port.an USB port.

Flash memory (USB)Flash memory (USB)

Flash memory storage devices are typically smallFlash memory storage devices are typically small removable and rewritable.removable and rewritable. They consist of a small printed circuit board which is They consist of a small printed circuit board which is

encased in plastic or metal casing for protection.encased in plastic or metal casing for protection. They are inserted into a USB port in the computerThey are inserted into a USB port in the computer

Advantages Disadvantages

Even more portable than CDs and floppy disks

Cost is more expensive that CDs and floppy disks.

Can hold even more data that CDs and floppy disks

Can easily be lost

Have outer case and cap for protection

Part which is inserted into USB port can easily be broken.

More fashionable and have fashionable looks

Zip disksZip disks

Zip disks look similar to a floppy disk but are Zip disks look similar to a floppy disk but are a little bit thicker.a little bit thicker.

They can store around 100Mb of data - 70 They can store around 100Mb of data - 70 times more than a floppy disk.times more than a floppy disk.

Advantages Disadvantages

Stores more data that a Floppy disk.

Almost extinct now

Compresses data, so more data can be stored.

Need a separate zip drive to read the disk

Portable More expensive than floppy disks

Magnetic tapesMagnetic tapes

Large organisations who need to back up their Large organisations who need to back up their systems use magnetic.systems use magnetic.

Magnetic tape uses 'serial access' to find a piece of Magnetic tape uses 'serial access' to find a piece of data. It works in much the same way as a video tape data. It works in much the same way as a video tape that you might have at home. To find a specific piece that you might have at home. To find a specific piece of data, you have to start at the beginning of the tape of data, you have to start at the beginning of the tape and continue fast forwarding until you get to the and continue fast forwarding until you get to the piece of data that you need. piece of data that you need.

Advantages Disadvantages

Cheap. Can be slow to access data.

Can store large amounts or data.

Need special equipment to read data.

Can back up overnight or over weekend.

Need special equipment to write data.

Floppy disksFloppy disks

A floppy disk can store up to 1.44 Mb of data which is equivalent to around 300 pages of A4 text. Floppy disks are a magnetic storage device.

Floppy disks are the oldest use of storage and are still used.

Floppy disksFloppy disks

AdvantagesAdvantages Portable.Portable. Cheap.Cheap. Useful for transferring Useful for transferring

small files.small files. Security tab to stop data Security tab to stop data

being over written.being over written. Can used many timesCan used many times

DisadvantagesDisadvantages Not very strong- easy to Not very strong- easy to

breakbreak Data can be erased if the Data can be erased if the

disk comes into contact with disk comes into contact with a magnetic fielda magnetic field

Quite slow to access and Quite slow to access and retrieve data when retrieve data when compared to a hard diskcompared to a hard disk

Can transport viruses from Can transport viruses from one machine to anotherone machine to another

Small storage capacitySmall storage capacity New computers may not New computers may not

have floppy disk readershave floppy disk readers

Quick quizQuick quiz

What does MB stand for?What does MB stand for?

A. A. Megabytes

B. B. Mean bear

C. C. Mini-bytes

D. D. Mega-burger?

QuestionQuestion

Quick quizQuick quiz

How many bytes make up 2MB?How many bytes make up 2MB?

A. A. 6 bites to finish the two Burger

B. B. Errrrmmmm none?

C. C. 2,000

D. D. 2,048

Quick quizQuick quiz

What does RAM stand for?What does RAM stand for?

A. A. Rock and Metal

B. B. Relative Application Measurement

C. C. Random Access Memory

D. D. Read and Memorize

Quick quiz

What is a type of Volatile memory?

A. RAM

B. ROM

C. Sodium Hydroxide

D. Me no speek English

Quick quiz

What is the usual size of RAM installed into a computer?

A. 1 terabyte

B. 20cmx40cm?

C. 0.00000002574591261 bites

D. 1 Gigabyte

ConclusionConclusion

Hope you have learned and expanded Hope you have learned and expanded your knowledge about storage devices.your knowledge about storage devices.

Thanks for watching.Thanks for watching. Source of information: Source of information: http://www.teach-http://www.teach-

ict.com/gcse/hardware/storage/miniweb/flict.com/gcse/hardware/storage/miniweb/floppydisk.htmoppydisk.htm