k.Suresh 2/4 IT-A

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MEMORY OR STORAGE DEVICES

What is Memory?What is Storage?Difference between Memory and Storage.Types of Storage Devices.Advantages and Applications.Conclusion.References.

Contents

• Memory is usually designed to store and retrieve data in word-length quantities. It is always based upon the semi conductor technology.

• Memory unit is called Random Access Memory(RAM).If any location can be accessed for a Read or Write operation in some fixed amount of time that is independent of the location address.

What is Memory

A storage device is any computing Hardware that is used for storing, porting and extracting data files and objects.

Storage is typically non-volatile in nature, means that it retains its state even when the power is off.

What is Storage

Memory v/s Storage The term Memory

refers to the amount of RAM installed in the computer.

Any data held in Memory is lost when the computer is turned off.

Ex:Desk

The term Storage refers to the capacity of the computer’s hard disk.

The information Stored on a hard disk remains intact even when the computer is turned off.

Ex:File cabinet.

Primary storage: is the storage provided by memory in a computer system e.g. ROM/RAMSecondary storage: is storage provided by peripheral devices other than memory e.g. Hard Disk, Floppy Disk, Magnetic tapes etc.

Storage Devices

• Primary storage devices are………… 1.Random Access Memory *Dynamic Ram *Static Ram 2.Read Only Memory *PROM *EPROM *EEPROM

Primary storage devices:

Dynamic RAM : loses its stored information in a very short time (for milli sec.) even when power supply is on. D-RAM’s are cheaper & lower.

Similar to a microprocessor chip is an Integrated Circuit (IC) made of millions of transistors and capacitors.

Dynamic Ram:

A type of RAM that is quicker than dynamic RAM and does not need to be refreshed. Because it is more expensive and holds less data than dynamic RAM, it is used primarily for cache memory.

Static Ram:

PROM is programmable ROM. Sometimes we may want to write some data on the ROM. In such cases we use PROM. Data can be written on it using special equipment.

Prom is important to note that data can be written on PROM only once but it cannot be removed from the PROM.

Programmable ROM(PROM):

EPROM is programmable ROM from which data can be programmed and erased. Note that programming and erasing is not limited to just one time.

EPROM is now used in most bios systems.This provides flexibility for the programmer.

EPROM:

EEPROM is the next generation of ROM. It takes EPROM to the next level. As compared to EPROM, EEPROM can be programmed using software technology.

The main advantage of this is you don't need special hardware to program it.

EEPROM:

Two main categories of storage technology used today are magnetic storage and optical storage

Magnetic Storage Devices 1.Hard Disk(Fixed and Portable) 2.Floppy Disk 3.Magnetic Tapes 4.Flash Memory Optical Storage Devices 1.Compact Disk(CD) 2.Digital V Disk(DVD)

Secondary Storage devices:

Fixed hard disksA hard disk drive is the device used to store large amounts of digital information in computers and related equipment like iPods and games consoles such as the Xbox 360 and PS3.

Hard disk drives are used to store operating systems, software and working data

.

Portable hard disksPortable hard discs are good fun because you can carry data about all over the place and transfer information, programs, pictures, etc between computers.

Floppy disksA floppy disk is a data storage medium that is composed of a disk of thin, flexible floppy)magnetic storage medium encased in a square or rectangular plastic shell.

Floppy disks are read and written by a floppy disk drive

Magnetic tapesMagnetic tape has been used for data storage for over 50 years. When storing large amounts of data, tape can be substantially less expensive than disk or other data storage options.

Tape storage has always been used with large computer systems.

• Nearly all computers today include a CD or DVD drive, usually located on the front of the system unit. CD drives use lasers to read (retrieve) data from a CD.

• Many CD drives can also write (record) data onto CDs. If you have a recordable disk drive, you can store copies of your files on blank CDs. You can also use a CD drive to play music CDs on your computer.

• DVD drives can do everything that CD drives can, plus read DVDs.

CDs and DVDs

. If you have a DVD drive, you can watch movies on your computer or play music CDs. Many DVD drives can record data onto blank DVDs.

Flash memory cards store computer information such as text, pictures, and music. You can erase and reuse memory cards over and over. Most digital cameras store pictures and video on a CompactFlash memory card or a Secure Digital (SD) card.

Flash Memory

Advantages:Greatly improved data cargo carrying

capacity (relative to the 1.44 Mb floppy disc).You don't need to worry about the other

person having the same type of special cartridge drive as yourself.

Disadvantages:Hard drives have to be handled quite

carefully, and when being transported should be wrapped in something soft and put in a padded bag.

More expensive than other forms of removable media.

Advantages and disadvantages :

Conclusion: