Download - 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.