memory organization

1. PRESENTATION BY
Abdullah Al Imran
ID:142-15-3690
COMPUTER
MEMORY

2. HISTORY
OF
MEMORY

3. DELAY LINE MEMORY
o Developed by J. Presper Eckert in the early 1940s.
o It is also used in digital computers.
o Delay line memory would be limited to a capacity of up to
a few hundred thousand bits to remain efficient.
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4. RANDOM ACCESS
COMPUTER MEMORY
o The Williams tube and Selectron tube originated in 1946.
o In 1947 Jay Forrester, Jan A. Rajchman and An
Wang developed magnetic core memory which allowed for
recall of memory after power loss.
o The Selectron was limited to 256 bits, while the Williams
tube could store thousands
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5. MAGNETIC CORE MEMORY
●It was the computer
memory of choice
throughout the 1960s,
until it was replaced by
semiconductor memory.
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6. Overview
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Primary
- storage of intermediate data
- necessary to run the computer
- RAM, Cache
Secondary
- long-term storage of data
- HDD
Tertiary
- CD, DVD, memory card...
Off-line
- disconnected storage
- unplugged USB flash drive
- external HDD

7. MEMORY
o It holds the data and instructions that the
Central Processing Unit (CPU) needs.
o It allows the CPU to direct interact with the
program.
o Memory is a need of every computer
o Main memory is divided into two parts :
- Random Access memory ( RAM ) should be
better known as Read Write Memory
- Read Only Memory (ROM)
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8. “
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Random Access Memory (RAM)
• Structure :
A set of memory chips, each of them is an
integrated circuit (IC) made of millions of
transistors and capacitors
• Volatile - their state is lost or reset when
power is removed from the system.
• Usage :
Holds data/application programs from input
devices or storages
• Bus : processing speed
• Types:
--DRAM
--SRAM

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Read only memory (ROM)
• Has contents which are fixed when
the chip is manufactured
• Holds the bootstrap loader part of
the operating system
• Retains its data when the computer
is switched off
•Types of ROM
--PROM
--EROM
--EEROM

10. 10
Cache memory
• Faster and expensive than RAM
• It improves the computer’s performance
• Processor can use it to store frequently
accessed data and program instructions
• It is two types :
- L1 : primary cache (inside the
processor)
- L2 : secondary cache (in the
motherboard or near the
microprocessor)

11. THANKS!
Any questions?
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