Types of memory

Types of Memories used in computer

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Objective
On completion of this period, you would be
able to learn:

 Functions of Memory.

 Types of Memory.


Recap

 Blocks in CPU
Control Unit & Arithmetic and Logical Unit.

 Functions of CPU
Performs calculations, takes decisions, and
controls all the units.


Memory

 A space to keep computer’s data.

 It stores program, data, results or any kind of
intermediate results.


Memory (contd...)

 Memory stores binary data i.e. 0’s and 1’s.


Types of Memory

 Primary memory (Semiconductor memory).

 Secondary memory (magnetic memory).

 Optical memory.


Primary memory:
 The semiconductor memory is employed as the
main memory (or primary memory).

 It stores programs and data which are currently
needed by the CPU.

 RAM and ROM ICs are used as the main
memory of the computer


Primary Memory (contd...)

 The storage type is temporary

 It is volatile memory

 Storage capacity is limited


Primary memory (contd):

 It is part of CPU.

 Used for storing a little volume of data at the
time of processing.


Secondary memory

The magnetic memory is called as the secondary
memory (auxiliary memory).

The information which is needed by the CPU for
current processing is transferred from the
secondary memory to the main memory.


Secondary memory (contd)

 This is non-volatile memory, i.e., data is stored
permanently.

 The secondary memory is used for bulk storage
(mass storage) of programs, data and other
information.


Secondary memory (contd)
 Storage capacity is enlarged.

 Used for preserving high volume of data for
future use

 The magnetic memories such as hard disk and
floppy disk are the most commonly used.


Types of memory
MEMORY
MEMORY

PRIMARY MEMORY
PRIMARY MEMORY SECONDARY MEMORY
SECONDARY MEMORY
(INTERNAL MEMORY)
(INTERNAL MEMORY) (EXTERNAL MEMORY)
(EXTERNAL MEMORY)

CPU
CPU
MAGNETIC MAGNETIC
MAGNETIC MAGNETIC OPTICAL
OPTICAL
ON CHIP TAPE
TAPE DISK
REGISTER ON CHIP DISK DISK
DISK
REGISTER CACHE
CACHE

RAM ROM
ROM
RAM

DRAM SRAM PROM
PROM EPROM
EPROM EEPROM
DRAM SRAM EEPROM


Random Access Memory (RAM)

 It is volatile memory i.e. temporary memory.

 Performs both read and write operations.

 Usually hidden to users.


TYPES OF RAM

Storage capacity is limited.

 DRAM

 SRAM


Static RAM

 Static RAM retains stored information only as
long as power supply is on.

 Static RAMs are costlier and consume more
power.


Static RAM (contd..)

 Static RAM is faster.
 It is used as cache memory.

 Static RAMs hold information in flip-flop,
consisting of two cross coupled inverters.


Dynamic RAM

 Dynamic RAM loses its stored information in a
very short time even though the power supply is
on.

 Only one transistor is needed to form a memory
cell and result in high packing density and
moderate speed.


Dynamic RAM (contd)

 They consume less power.

 They are used where large capacity of memory
is needed.

 Dynamic RAM is cheaper.

 It is used as main memory.


Random Access Memory

Fig 1


Read Only Memory (ROM)

 It is non-volatile memory .i.e. permanent storage.

 Performs only read operations.

 Limited storage capacity.


Types Of ROM

1. PROM - (Programmable Read Only
Memory)

2. EPROM - (Erasable Programmable
Read Only Memory)

3. EEPROM - (Electrically Erasable PROM)


Cache Memory

 Cache memory is placed between the CPU and
the main memory.

 It stores instructions and data which are to be
immediately executed.


Cache Memory (contd...)

It is not accessible to users i.e. information
cannot be written into cache memory by users.

It increases the performance of the computer
up to 15%.


Summary

In this class, we have learnt about

 Functions of memory.

Types of memory.


Frequently Asked Questions

1. Explain the types of memories?

2. Explain the functions of memory?


Quiz

1. Is RAM a Volatile memory?
a. No
b. Yes


Quiz:

2. Is ROM a Non volatile memory?
a. Yes
b. No


Quiz

3. What is the form of data in the memory?
a. Decimal
b. Binary
c. Octal
d. Hexadecimal


Types of memory

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Types of memory