National Institute of Electronic

and Information Technology

Ministry of electronics and information
technology

A Project Report on
Types of memory
Submitted By
Shubhranshu kumar mishra
Registration no: 1573076
Date of submission: 30 jun 2024
Under the guidance of
MR .Nayem Ansari
Submitted in Practical fulfillment of the
requirements for qualifying ‘O’ Level

Name and address the accreditations:

Madhur Computers, Apple Home Shahpura Kothi Near Junglinath Mandir,
Lakhimpur-kheri, Dist-kheri Uttar Pradesh Pin-262701

Under the guidance Examiner Center Head

 AKNOWLEDGEMENT
Last but not the least I am thankful
to God for giving me the ideas in
completing this. I would like
express my gratitude towards my
subject teacher for my providing to
me opportunity to make the
project.

Thank
You
 CERTIFICATE
This is to certify that the project
ENTITI.ED “types of memory”
Submitted by “shubhranshu Kumar
Mishra” in practical fulfillment of the
Requirement For the award of ‘o’
Level at “MADHUR COMPUTERS” is an
automatic work carried out by him
under. My Supervision and Guidance.
Date:30 Jun 2024
MR. Nayem Ansari

Memory
●
●

A computer is an electronic device and that accepts data,

processes on that data, and gives the desired output. It
performs programmed computation with accuracy and
speed. Or in other words, the computer takes data as input
and stores the data/instructions in the memory (use them
when required). After processes the data, it converts into
information. Finally, gives the output.
Here, input refers to the raw data that we want the
machine to process and return to us as a result, output
refers to the response that the machine provides in
response to the raw data entered and the processing of
data may involve analyzing, searching, distributing,
storing data, etc. Thus, we can also call a computer data
processing system.
What is Computer Memory?
Computer memory is just like the human brain. It is used
to store data/information and instructions. It is a data
storage unit or a data storage device where data is to be
processed and instructions required for processing are
stored. It can store both the input and output can be stored
here.
Characteristics of Computer Memory
● It is faster computer memory as compared to secondary

memory.
● It is semiconductor memories.

● It is usually a volatile memory, and main memory of

the computer.
● A computer system cannot run without primary

memory.

How Does Computer Memory Work?

When you open a program, it is loaded from secondary
memory into primary memory. Because there are various
types of memory and storage, an example would be
moving a program from a solid-state drive (SSD) to
RAM. Because primary storage is accessed more quickly,
the opened software can connect with the computer’s
processor more quickly. The primary memory is readily
accessible from temporary memory slots or other storage
sites.

Memory is volatile, which means that data is only kept

temporarily in memory. Data saved in volatile memory is
automatically destroyed when a computing device is
turned off. When you save a file, it is sent to secondary
memory for storage.
There are various kinds of memory accessible. It’s

operation will depend upon the type of primary memory

used. but normally, semiconductor-based memory is more
related with memory. Semiconductor memory made up
of IC (integrated circuits) with silicon-based metal-oxide-
semiconductor (MOS) transistors.

Types of Computer Memory

In general, computer memory is of three types:
● Primary memory

● Secondary memory

● Cache memory
Now we discuss each type of memory one by one in
detail:

1. Primary Memory
It is also known as the main memory of the
computer system. It is used to store data and programs or
instructions during computer operations. It uses
semiconductor technology and hence is commonly called
semiconductor memory. Primary memory is of two types:

● RAM (Random Access Memory): It is a volatile

memory. Volatile memory stores information based on
the power supply. If the power supply fails/
interrupted/stopped, all the data and information on this
memory will be lost. RAM is used for booting up
or start the computer. It temporarily
stores programs/data which has to be executed by
the processor.
RAM is two types:
● S RAM (Static RAM): S RAM uses
transistors and the circuits of this memory are
capable of retaining their state as long as the
power is applied. This memory consists of the
number of flip flops with each flip flop storing 1
bit. It has less access time and hence, it is faster.
● D RAM (Dynamic RAM): D RAM uses
capacitors and transistors and stores the data as a
charge on the capacitors. They contain thousands
of memory cells. It needs refreshing of charge on
capacitor after a few milliseconds. This memory is
slower than S RAM.
ROM (Read Only Memory): It is a non-volatile
memory. Non-volatile memory stores information even
when there is a power supply failed/
interrupted/stopped. ROM is used to store information
that is used to operate the system. As its name refers to
read-only memory, we can only read the programs and
data that is stored on it. It contains some electronic
fuses that can be programmed for a piece of specific
information. The information stored in the ROM in
binary format. It is also known as permanent memory.
ROM is of four types:

● MROM(Masked ROM): Hard-wired devices

with a pre-programmed collection of data or
instructions were the first ROMs. Masked ROMs
are a type of low-cost ROM that works in this
way.

● PROM (Programmable Read Only

Memory): This read-only memory is modifiable
once by the user. The user purchases a blank
PROM and uses a PROM program to put the
 required contents into the PROM. Its content
can’t be erased once written.

● EPROM (Erasable Programmable Read Only

Memory): EPROM is an extension to PROM
where you can erase the content of ROM by
exposing it to Ultraviolet rays for nearly 40
minutes.

● EEPROM (Electrically Erasable

Programmable Read Only Memory): Here the
written contents can be erased electrically. You
can delete and reprogramme EEPROM up to
10,000 times. Erasing and programming take
very little time, i.e., nearly 4 -10
ms(milliseconds). Any area in an EEPROM can
be wiped and programmed selectively.

2. Secondary Memory
It is also known as auxiliary memory
and backup memory. It is a non-volatile memory and used
to store a large amount of data or information. The data or
information stored in secondary memory is permanent,
and it is slower than primary memory. A CPU cannot
access secondary memory directly. The data/information
from the auxiliary memory is first transferred to the main
memory, and then the CPU can access it.

Characteristics of Secondary Memory

● It is a slow memory but reusable.
● It is a reliable and non-volatile memory.
● It is cheaper than primary memory.
● The storage capacity of secondary memory is large.
● A computer system can run without secondary memory.
● In secondary memory, data is stored permanently even
when the power is off.

Types of Secondary Memory

1. Magnetic Tapes: Magnetic tape is a long, narrow

strip of plastic film with a thin, magnetic coating on
it that is used for magnetic recording. Bits are
recorded on tape as magnetic patches called
RECORDS that run along many tracks. Typically, 7
or 9 bits are recorded concurrently. Each track has
one read/write head, which allows data to be
recorded and read as a sequence of characters. It can
be stopped, started moving forward or backward, or
rewound.
2. Magnetic Disks: A magnetic disk is a circular metal or
a plastic plate and these plates are coated with magnetic
material. The disc is used on both sides. Bits are stored in
magnetized surfaces in locations called tracks that run in
concentric rings. Sectors are typically used to break tracks
into pieces.

Hard discs are

discs that are
permanently attached and cannot be removed by a single
user.
3. Optical Disks: It’s a laser-based storage medium that
can be written to and read. It is reasonably priced and has
a long lifespan. The optical disc can be taken out of the
computer by occasional users.
Types of Optical Disks
CD – ROM
● It’s called compact disk. Only read from memory.

● Information is written to the disc by using a controlled

laser beam to burn pits on the disc surface.

● It has a highly reflecting surface, which is usually

aluminium.
● The diameter of the disc is 5.25 inches.

● 16000 tracks per inch is the track density.

● The capacity of a CD-ROM is 600 MB, with each

sector storing 2048 bytes of data.

● The data transfer rate is about 4800KB/sec. & the new

access time is around 80 milliseconds.

WORM-(WRITE ONCE READ MANY)
● A user can only write data once.

● The information is written on the disc using a laser

beam.
● It is possible to read the written data as many times as

desired.
● They keep lasting records of information but access

time is high.
● It is possible to rewrite updated or new data to another

part of the disc.

● Data that has already been written cannot be changed.

● Usual size – 5.25 inch or 3.5 inch diameter.

● The usual capacity of 5.25 inch disk is 650 MB,5.2GB

etc.
DVDs
● The term “DVD” stands for “Digital Versatile/Video

Disc,” and there are two sorts of DVDs:

● DVDR (writable)

● DVDRW (Re-Writable)

● DVD-ROMS (Digital Versatile Discs): These are

read-only memory (ROM) discs that can be used in a

variety of ways. When compared to CD-ROMs, they
can store a lot more data. It has a thick polycarbonate
plastic layer that serves as a foundation for the other
layers. It’s an optical memory that can read and write
data.
● DVD-R: DVD-R is a writable optical disc that can be

used just once. It’s a DVD that can be recorded. It’s a

lot like WORM. DVD-ROMs have capacities ranging
from 4.7 to 17 GB. The capacity of 3.5 inch disk is 1.3
GB.
3. Cache Memory
It is a type of high-speed semiconductor memory that can
help the CPU run faster. Between the CPU and the main
memory, it serves as a buffer. It is used to store the data
and programs that the CPU uses the most frequently.
Advantages of Cache Memory
● It is faster than the main memory.

● When compared to the main memory, it takes less time

to access it.
● It keeps the programs that can be run in a short amount

of time.
● It stores data in temporary use.

Disadvantages of Cache Memory

● Because of the semiconductors used, it is very

expensive.
● The size of the cache (amount of data it can store) is

usually small.
Characteristics of Memory in Computer
The following are the characteristics of memory in
computer:
1. The storage capacity varies for different types of
memories in computers. The storage capacity of
external devices is measured in bytes, while internal
memory is measured either in words or bytes. Storage
word length may vary in 8, 16, or 32 bits.

2. Unit of transfer measures the transfer rate of bits that

can be either read or written in and out of memory
devices. This data transfer rate is different in internal
and external devices. For internal memory, it is usually
equal to word size and for external memory, it is
greater than a word.

3. The internal memory in a computer is inbuilt within it,

whereas external memory is present as a separate
storage device such as USB or disk.

4. There are four methods to access memory, including

DMA, Associative Access Method, Sequential Access
Method, and Random Access Method.
5. Memory in computers has different physical behavior,
such as volatile, non-erasable, and non-volatile
memory.

6. The performance of the memory depends on access

time, memory cycle time and transfer rate. Access time
is the total time taken by memory devices to perform
read and write operations.

7. Memory cycle time is the total time needed to access

the memory block and the additional time needed
before starting the second access.

RAM ROM

It stands for Random It stands for read only

access memory. memory.

It is slower memory as
It is the fastest memory.
compare to RAM.

It is volatile memory. It is non-volatile memory.

In this memory, data will

In this memory, data will not
erase when the power is
erase even if the power is off
off
How does computer memory
work?
A program is loaded from secondary memory to primary
memory when it is opened. There are several types of
memory and storage, for example, a program being
moved from a solid-state drive (SSD) to RAM (Random
Access Memory). The opened software will be able to
communicate with the computer's processor at a faster
rate because primary storage is accessed more quickly.
The main or primary memory can be accessed quickly
from storage locations such as temporary memory slots.
Data in memory is only saved temporarily since memory
is volatile. Data saved in volatile memory will be erased
immediately whenever a computer is turned off. A file is
transported to secondary memory for permanently storage
when it is saved.
There are numerous kinds of memory present in a
computer. Depending on the primary memory utilized, it
will perform differently, but semiconductor-based
memory is typically connected with memory. Integrated
circuits utilizing metal-oxide-semiconductor (MOS)
transistors based on silicon will be used to make
semiconductor memory.
Functions of Computer Memory
o Data Storage: The primary role of computer
memory is to keep data. This includes the OS,
software packages, and user-generated documents.
The hierarchical arrangement guarantees that the
most regularly accessed data is stored in the fastest,
smallest sort of memory.

o Program Execution: When software is launched, it's

loaded into RAM for execution. The CPU fetches
commands and facts from RAM, and the quicker
cache memory, when possible, performs the critical
computations. The rate and overall performance of
this approach impact the overall performance of the
PC.

o Temporary Storage: Memory is used for brief

storage of records throughout ongoing operations.
For example, at the same time as you edit a
document, the adjustments are quickly saved in RAM
until you save the file. This temporary storage is
crucial for seamless individual considerations.
 o Caching: Cache memory performs a pivotal function
in caching regularly accessed information. By
preserving a copy of these records near the CPU,
cache memory reduces the time needed to retrieve
information, enhancing the overall speed of the
system.

o Virtual Memory: Operating structures use a concept

known as virtual memory to simulate larger RAM
capacities than are physically available. This includes
the use of a part of RAM. While virtual memory
allows the execution of larger applications, it's slower
than physical RAM.
In general, memory can be classified into primary and
secondary memory, however even when just talking about
primary memory, there are many different types of
memory. There are some examples of primary memory,
such as follows:
o Cache memory: The cache, also known as a
temporary storage area, is more readily available to
the processor as compared to the main memory
source of the computer system. It is mounted on a
different chip that connects to the CPU via a bus or is
frequently built directly into the CPU chip; hence, it
is also known as CPU memory.
o RAM: The term refers to the fact that the processor
can directly access any storage location. Random
Access Memory, or RAM, is a piece of hardware that
serves as the internal memory of the CPU. It is often
found on a on the motherboard of a computer. When
the computer is turned on, it enables the CPU to store
programs, information, and result of the program.
Also, it is a computer's read-write memory, which
means data can be added to it as well as read from it.

o Dynamic RAM: A type of random-access memory

that is used in computing systems (primarily PCs) is
called dynamic random-access memory (DRAM).
The data or program code required for a computer
processor to operate is often stored in DRAM, which
is a kind of semiconductor memory. Each piece of
data is stored in DRAM in its own passive electrical
component, which is located inside an integrated
circuit board. Each electrical component has two
value states, known as 0 and 1, in one bit.
o Static RAM: As long as SRAM receives power, it
keeps data bits in its memory. It does not need to be
refreshed on a regular basis, in contrast to DRAM,
which stores bits in cells made up of a capacitor and a
transistor.

o Double Data Rate SDRAM: Theoretically, DDR

SRAM can increase the memory clock speed to at
least 200 MHz. It is an SDRAM.

o Double Data Rate 4 Synchronous Dynamic

RAM: DDR4 RAM is the successor to its preceding
DDR2 and DDR3 iterations. It is a kind of DRAM
that contains a high-bandwidth interface. Higher
module density and lower voltage requirements are
both possible with DDR4 RAM. It enables dual in-
line memory modules (DIMMS) up to 64 GB; Also,
higher data rate transfer speeds are paired with it.

o Rambus Dynamic RAM: A memory component

called DRDRAM made a guarantee to transport up to
1.6 billion bytes per second. The RAM controller
subsystem consists of RAM, a bus connecting RAM
to the microprocessor, and computer-using devices
that make up the subsystem.
o Read-only memory: ROM is often only read from
and not written to, which is a type of computer
storage. It is nonvolatile in nature, which means it
stores data permanently. The programming code is
stored in the ROM that enables a computer system to
boot up or regenerate every time when it is turned on.

o Programmable ROM: PROM is ROM that a user

can modify only once. Using a unique device known
as a PROM programmer enables a user to customize
a microcode program.

o Erasable PROM: EPROM is a type of computer

memory that can be erased and re-used. It is
programmable read-only memory PROM.

o Electrically erasable PROM: A user-modifiable

ROM called an EEPROM can be repeatedly wiped
and reprogrammed with the help of an using
electrical voltage that is higher than usual. Unlike
EPROM chips, EEPROMs can be changed without
being taken out of the computer. However, an
 EEPROM chip must be completely deleted and
reprogrammed, not just some parts of it.

o Virtual memory: A memory management method

that enables the use of secondary memory just like it
was a component of main memory. In order to
compensate for physical memory shortages, virtual
memory uses hardware and software to temporarily
shift data from RAM to disk storage.

End Project