PRIMARY PRIMARY MEMORY OF MEMORY OF COMPUTERCOMPUTER

WELCOME TO MY PRESENTATION

Presenter

SYED HAMIDUR RAHMANID:16161037DEP OF PUBLIC ADMINISTRATION

BANGLADESH UNIVERSITY OF PROFESSIONALS

DEFINITION

Primary storage, also known as main storage or memory, is the area in a computer in which data is stored for quick access by the computer's processor.

The terms random access memory (RAM) and memory are often as synonyms for primary or main storage.

Primary Memory also called main memory. Main memory is directly or indirectly connected to the central processing unit via a memory bus .The CPU continuously reads instructions stored there and executes them as required.

Example:

1: Ram2: Rom3:Cache

Primary Memory has limited capacity and data is lost when power is switched off. It is generally made up semiconductor device.

Characteristics of Main /Primary Memory :

1:These are semiconductor.

2: It is known as main memory.

3: Usually volatile memory

4: Data is lost in case power is switched off.

5: It is working memory of the computerFaster than secondary memories.

6:A computer cannot run without primary memory.

Function of Primary Memory:

RAM(Random Access Memory):

• The read & write m/y of a computer is called RAM. • The users can write information into RAM and read

information from it.

• It possesses random access property.

• In this m/y can be accessed on a random manner.

• It is a volatile memory.

Types of RAM

1:SRAM

2:DRAM

3:SDRAM 4:DDR2 RAM

SRAM:Static Random Memory Access

The information need to be refreshed.In this it retain stored information only as long as the power supply is on.

SRAM stands for static RAM, which is so named because it does not need the periodic refresh rates like DRAM. Because of how SRAMs are designed, not only are refresh rates unnecessary, but SRAM is much faster than DRAM and much more capable of keeping pace with modern processors.

DRAM(dynamic random access memory:

Dynamic RAM (DRAM) is the types of memory chip used for most of the main memory in a modern PC.

The main advantages of DRAM are that it is very dense, meaning you can pack a lot of bits into a very small chip, and it is inexpensive, which makes purchasing large amounts of memory affordable.

Double data rate synchronous dynamic random-access memory (DDR SDRAM) is a class of memory integrated circuits used in computers.

The DDR SDRAM interface makes higher transfer rates possible by more strict control of the timing of the electrical data and clock signals

DDR SDRAM:

DDR2 SDRAM

DDR2 is simply a faster version of DDR memory: It achieves higher throughput by using differential pairs of signal wires to allow faster signaling without noise and interference problems.

DDR2 is still double data rate, just as with DDR, but the modified signaling method enables higher clock speeds tobe achieved with more immunity to noise and cross-talk between the signals.

ROM(Read only Memory):

Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all,

so it is mainly used to store firmware (software that is closely tied to specific hardware and unlikely to need frequent updates) or application software in plug-in cartridges.

Types of Rom: There are different variations on the classic ROM chips which were manufacturer produced and could not change. The most common are: 1: PROM

2: EPROM

3: EEPROM

PROM(Programmable read-only memory):

A programmable read-only memory (PROM) or field programmable read-only memory (FPROM) or one-time programmable non-volatile memory (OTP NVM) is a form of digital memory where the setting of each bit is locked by a fuse or anti fuse.

It is one of the type of ROM (read-only memory). The data in them is permanent and cannot be changed.

EPROM(Erasable programmable read-only memory) :

An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of memory chip that retains its data when its power supply is switched off.

Computer memory that can retrieve stored data after a power supply has been turned off and back on is called non-volatile.

EEPROM (Electrically Erasable Programmable Read-Only Memory):

This type of ROM works in a similar way to Flash memory in that it can its contents can be 'flashed' for erasure ad then written to without having to remove the chip from its environment.

EEPROMs are used to store a computer system's BIOS, and can be updated without returning the unit to the factory.

Thanks TO All