1. MEMORY
Prepared by -Shiv B.saud (1247138)
-Siddhant bhattarai (1247170)

2. Memory
 Memory stands for that thing that store
something.
 Like our brain computer have also storing unit
called memory unit.
 From memory information data are stored and
fetch when required.
 In computer memory there is no data loss
problem.
 Without memory unit a computer can’t perform its
operation.
 Example hard disk, CD etc.

3. Types of memory
 There are two types of memory used inside
computer system and they are-
 1.primary memory
 2. secondary memory
 1.Primary memory is also known as the
temporary memory because it only store data
when that are at processing stage and after that it
do not store it. Primary memory have less storing
capacity as compared to secondary.

4. Primary memory are two types
 RAM
 The RAM is a volatile memory, it means information
written to it can be accessed as long as power is on.
As soon as the power is off, it can not be accessed.
so this mean RAM computer memory essentially
empty.RAM holds data and processing instructions
temporarily until the CPU needs it.
 There are two basic types of RAM :
 (i) Dynamic Ram
 (ii) Static RAM

5.  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
 . Static RAM uses a completely different
technology. S-RAM retains stored information
only as long as the power supply is on. Static
RAM’s are costlier and consume more power.
They have higher speed than D-RAMs. They
store information in Hip-Hope.

6. ROM
 Read only memory (ROM) is an example of
nonvolatile memory. ROM is a class of storage
medium used in Computers and other electronic
devices. Read Only Memory (ROM), also known
as firmware, is an integrated circuit programmed
with specific data when it is manufactured.
 Types of ROM
 PROM
 EPROM
 EEPROM

7.  PROM : Short for programmable read-only
memory, a memory chip on which data can be
written only once. Once a program has been
written onto a PROM, it remains there forever.
 EPROM : Erasable programmable read-only
memory, and pronounced e.e-prom, EPROM is a
special type of memory that retains its contents
until it is exposed to ultraviolet light.
 EEPROM : Short form of electrically erasable
programmable read-only memory. EEPROM is a
special type of PROM that can be erased by
exposing it to an electrical charge. Like other
types of PROM, EEPROM retains its contents
even when the power is turned off. Also like other
types of ROM, EEPROM is not as fast as RAM

8. 2. Secondary memory
 It is also known as the permanent storing device
and it also store all the data and information
permanently. It is also have huge capacity as
compared to the primary memory and store all
data and information.
 Types of secondary memory
 Hard disk
 CD ROM
 DVD
 Pen drive

9.  Hard disk
A hard disk is part of a unit, often called a "disk
drive,""hard drive," or "hard disk drive," that stores
and provides relatively quick access to large
amounts of data on an electromagnetically
charged surface or set of surfaces. Today's
computers typically come with a hard disk that
contains several billion bytes (gigabytes).

10. CD ROM
 Compact Disc-Read Only Memory, CD-
ROM drives or optical drives are CD players
inside computers that can have speeds in the
range from 1x and beyond, and have the
capability of playing audio CDs and computer
data CDs. Below is a picture of the front and back
of a standard CD-ROM drive.

11. DVD’S
 A Digital Versatile Disc - Read Only Memory,
or DVD-ROM, is a media storage disk that closely
resembles a CD or compact disc. The major
difference is that the DVD is formatted to hold far
more data. A CD commonly has a capacity of 650
megabytes, while the smallest capacity DVD can
store about seven times more data, or 4.38
gigabytes (GB).