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POWER POINT PRESENTATION

SECONDARY STORAGE DEVICESAND THEIR CHARACTERISTICS

BY:PRATIKSHA MESHRAM &SUPRIYA CHIMANKAR

INDEX

Introduction List of Storage Devices1]Magnetic Tapes2] Magnetic Disk3]Floppy Disk4]Optical Disk5]Memory card6]DVD7]Pendrive/Flash drive

INTRODUCTION Computer data storage, often called storage

or memory, is a technology consisting of computer components and recording media used to retain digital data. It is a core function and fundamental component of computers. The central processing unit (CPU) of a computer is what manipulates data by performing computations. In practice, almost all computers use a storage hierarchy, which puts fast but expensive and small storage options close to the CPU.

There are three types of storage:i. Primary Storageii. Secondary storageiii. Tertiary storage

TYPES OF STORAGE

Primary Storage

Primary storage, often referred to simply as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required.

Secondary Storage

Secondary storage is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage.It don’t loose the data when computer is powered down.

Tertiary Storage

Tertiary storage, provides a third level of storage. It involves a robotic mechanism which will mount (insert) and dismount removable mass storage media into a storage device according to the system's demands.

GDD MAGNETIC TAPES

This storage devices is used where sequential data and processing is used .The tapes have high durability power and can be erased and refused again and again.Advantages:-Economical in nature, gives fast input and output,its reusable,long term storage.Disadvantages:-Only sequently recording & accessing.Inconvenient for storing large number of small records.For drives it makes compatibility difficult.

STRUCTURE

The tape is a pastic ribbon usually ½ inch wide that is coated on one side with an iron-oxide material which has high quality and more durable

MAGNETIC DISK It is a memory device in which a number of

disk make a disk pack.The surface of each recording surfaces in a 6 disk pack.

It’s a read/write disk.The disk when loaded is drive at a high number of revoluteAnd acess is made on surface when the disk revolve.There are two types:1]Hard disk 2]Removable disk

ADV. & DISADV. OF MAGNETIC DISKS

Advantagesi. Large capacity

storage.ii. Reusuable disks.iii. Have ability to

store data.

Disadvantagesi. Costlier than

tapes.ii. More susceptional

to errors.

FLOPPY DISK

Magnetic disk[floppy disk] is also used as an auxilary storage medium.Its use is limited to small computer based system.

Advantages : Floppy disks are- Compact ,reusable and cheap. Disadvantages : Floppy disks are more prone to data loss and

it is difficult to handle

STRUCTURE OF FLOPPY DISK

These are normally 3 ½ inch in diameter and with storage capacity 1.44

MB.They have a plastic cover which keeps the whole disk surface covered and protected when not in use.

OPTICAL DISK

Optical disk are ROM ,pre-recorded by themanufacturer.The disk is flat round in shapemade up of a resin.These work under the same principle that is used for the domestic compactdisk which have become very popular.They have large capacity and less error prone.But these are having high cost and are nonreusable

STRUCTURE

DVD

Digital Video Disk are new type of CD-ROMs that hold a minimum of 4.7 GB almost 2 hrs recording and have normal size of 4.7 inches.

The Digital sound can be seperated into discrete channels making surrounding sound possible.

Advantages :- Good storage capacity,reusable.

Disadvantages:-i. Limitated memoryii. Delicate structure

MEMORY CARDS/FLASH CARD

A memory card or flash card is an electronic flash memory data storage device used for storing digital information. They are commonly used in many electronic devices, including digital cameras, mobile phones, laptop computers, MP3 players and video game consoles. They are small in size.

Adv. :-Re-recordable, and able to retain data without power.

Disadv. :- Limitated memory and

DIFFERENT TYPE OF MEMORY CARDIT IS AVAILABLE IN 2GB,4GM,8GB,16GB,32GBAND SO ON.

PEN/FLASH DRIVE

Pen drive is one of those plug and play devices.It does not need a Data stored on flash drives is impervious to mechanical shock, magnetic fields, scratches and dust. These properties make them suitable for transporting data from place to place and keeping the data readily at hand.software to use.

Advantages:-Use a little power,most capacities are small and light.

Disadvantages:-more expensive and available capacity is increasing with time.

PENDRIVE

They are available in GB : 2GB,4GB,8GB,16GB,32GB…SO ON

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