COMPUTER MEMORY

PRESENTATION BY NIKUNJ PATEL

HISTORY OF

MEMORY

HISTORY OF MEMORY

In the early 1940s, memory technology mostly permitted a capacity of a few bytes.

ENIAC(Electronic Numerical Integrator And Computer): Firs electronic general-purpose computer .

That is capable of being reprogrammed to

solve a large class of numerical problems.

DELAY LINE

MEMORY

DELAY LINE MEMORY

developed by J. Presper Eckert in the early 1940s.

It is also used in digital computers.

Delay line memory would be limited to a capacity of up to a few hundred thousand bits to remain efficient.

RANDOM ACCESS COMPUTER MEMORY

RANDOM ACCESS COMPUTER MEMORY

The Williams tube and Selectron tube originated in 1946.

In 1947  Jay Forrester, Jan A. Rajchman and An Wang developed magnetic core memory which allowed for recall of memory after power loss.

The Selectron was limited to 256 bits, while the Williams tube could store thousands

RANDOM ACCESS COMPUTER MEMORY

MAGNETIC CORE

MEMORY

MAGNETIC CORE MEMORY

It was the computer memory of choice throughout the 1960s, until it was replaced by semiconductor memory.

MEMORY

MEMORY It holds the data and instructions that the

Central Processing Unit (CPU) needs.

Before a program can be run the program is loaded from the storage medium into memory.

It allows the CPU to direct interact with the program.

Memory is a need of every computer

TYPES OF MEMORY

TYPES OF MEMORY

ROM (Read Only Memory)

RAM (Random Access Memory)

Cache memory

Flash memory

READ ONLY MEMORY

stores data without electrical current; it is the ROM (Read Only Memory)

or is sometimes called non-volatile memory as it is not erased when the system is switched off

RAM

Random Access Memory, can be accessed randomly. Any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.

DDR2 RAM & DDR3 RAM

TYPES OF RAM

TYPES OF RAM

There are two different types of RAM:

DRAM (Dynamic Random Access Memory)

SRAM (Static Random Access Memory).

DRAM Needs to be refreshed thousands of times

per second while. Dynamic RAM needs to automatically

refresh thousands of times per second; that's where it gets the name dynamic. Otherwise, it will forget the information it's holding.

SRAM

Does not need to be refreshed, which is what makes it faster than DRAM.

Both types of RAM are volatile, meaning that they lose their contents when the power is turned off.

CACHE MEMORY

CACHE MEMORY

The cache is a smaller, faster memory which stores copies of the data from frequently used main memory locations.

FLASH MEMORY

FLASH MEMORY

Non volatile memory can be erased electronically and rewritten similar to EEPROM.

Introduced by Toshiba in 1984.

Most computers use it to hold up their startup instructions.

Also used in many mobiles , smart phones , digital cameras and PDA.

FLASH MEMORY

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