MEMORY OF THE COMPUTER

7/29/2019 MEMORY OF THE COMPUTER

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PRESENTATION ON MEMORY OF THE

COMPUTER


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WHAT IS MEMORY

The cognitive processes whereby past experience is

remembered.

Memory is collection of flip-flops which have inbuilt

fabrication of millions of transisters and capacitaters which

holds data in 0's and 1's.

Capacitor acts as a holding cell for binary data,transisters

allow memory circuitry to read

The common unit describing a computer memory is byte.

It is the amount of memory required to store a

character,integer or fraction.


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FUNCTIONS OF MAIN MEMORY

To act as buffer between the CPU and rest of

the computer system.

When the computer is off the main memory is

empty ; when the computer is on the main

memory is capable of receiving and holding a

copy of software instructions.

Temporary storage of a copy of applications.


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TYPES OF INTERNAL MEMORY

Memory

Non Volatile Volatile

Hard-Disk, CD, DVD, Floppy Disk,

Magnetic Tape, USB Flash memory, SD

Card

ROM

FLASH

PROM

EPROM

EEPROM

RAM

Static

Dynamic


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CMOS

(COMPLEMENTARY METAL-OXIDE

SEMICONDUCTOR) It is known as non-

volatile RAM or CMOSRAM.

It is an on-boardsemiconductor chippowered by CMOSbattery inside the

computer that storesinformation such assystem time and systemsettings for computer.


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It is used in batteries ,

motherboard, BIOSetc

It is used in integrated

circuits, static RAM,

logic circuits, analog

circuits, image

sensors.

It has high noiseimmunity and low

static power

consumption.


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ROM

(READ ONLY MEMORY)

It is a non-volatile memory and never loses itscontents.

Data is stored permanently and thus can never bemodified.

Mainly used in firmware, in computers to storelook up tables for evaluation of mathematical andlogical functions.

Useful for binary storage of cryptographic data toenhance information security.


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TYPES OF ROM

PROM

EPROM

EEPROM.


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PROM

(Programmable Read Only Memory)

It can be written to or programmedby PROM programmer.

It uses high voltage to permanently

destroy or create internal linkswithin a chip.

It can be programmed only once.


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EPROM

Erasable Programmable Read Only

Memory It can be erased by

exposure to strong

UV light. Endurance of most

EPROM chips

exceeds thousandcycles of erasingandreprogramming.

EEPROM


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EEPROM

(Electrically Erasable Programmable

Read Only Memory )

It is similar to

EPROM but allowsits contents to beelectrically erased.

Writing and flashingan EEPROM is muchslower than readingfrom ROM


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RAM

(RANDOM ACCESS MEMORY)

It is the most common type of memory,

volatile and thus loses its contents when

computer is shut off or due to power failure.

It is like an electronic scratch pad inside the

computer and holds data and program

instructions while the CPU works with them.


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RAM

(RANDOM ACCESS MEMORY)

It takes the form of integrated circuits that

allow to store data to be accessed in any order

i.e. , at random.

It has tremendous impact on the speed and

power of computer.


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SRAM

Static Random

Access Memory.

It uses multiple

transistors, two or

four for each

memory cell but

doesnt have a

capacitor in each

cell.


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Static indicates noneed to refresh as ituses bi-stable

latching circuitry tostore each bit.

It gives faster accessto data.

SRAM consumesmore power.

DRAM


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DRAM

Dynamic Random Access Memory

It stores each bit of data in a separate

capacitor within an integrated circuit.

It has memory cells with a paired transistors

and capacitors requiring constant refreshing

It consumes more power.

It is cheaper and smaller.


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DIFFERENCE BETWEEN RAM & ROM

RAM

Volatile in nature.

Temporary storage of data.

Data is both written andread from this memory as

well.

It has tremendous impact

on the speed and power ofcomputer.

ROM

Non-volatile in nature.

Permanent storage of data.

Data can only be read.

It doesn't have any such

function .


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CACHE MEMORY

It is a small amount of

(less than 1MB)high

speed memory resides

very close to CPU.

It is designed to supply

the CPU with most

frequent requested data. It takes a fraction of time

to access cache memory.


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TYPES OF CACHE MEMORY

Level 1-It is the CPU resident cache, it holds

instructions that have recently run.

Level 2- This is used in mother board to add

more speed, it hold potential upcoming

instructions.


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DIFFERENCE BETWEEN L1 & L2 CACHE

L1CACHE

It is primary cache.

It is extremely quick but

also expensive. It is fast memory.

It is very small from 8kb to

64kb.

L2 CACHE

It is secondary cache.

It is larger but slightly

slower than L1. Most processors have L2

about 256kb.

It usually from 64kb to 2MB

in size.


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FLASH MEMORY

Flash memory is a constantly powered non-

volatile memory that can be erased and

reprogrammed in units of memory called

blocks.It is often used to hold control codes

such as BIOS.

ADVANTAGES:

1.Faster data access time

2.Enormously durable.


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Resist better kinetic shock,withstand pressure

and high temperature.

Applications:

Memory cards

UB flash drives

Laptops


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VIRTUAL MEMORY

Virtual memory gives an application program theimpression that it has contiguous workingmemory.

This memory makes the programming of largeapplications easier and efficient. APPLICATIONS:

Spreadsheets

Multimedia play.


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AUXILLIARY MEMORY..

These are additional cheaper storage devices

used to serve as a back up for storing

information for future use by CPU.

It handles business , scientific and technical

applications.

The secondary storage is almost indispensible

if one really want to fully exploit the computer

potential.

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MEMORY OF THE COMPUTER