The document discusses the history and types of random access memory (RAM). It notes that the first form of RAM was cathode ray tubes in 1947, followed by magnetic-core memory in 1955. Modern RAM was introduced in 1969 by Intel. The document then describes different types of RAM including static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), direct Rambus DRAM (DRDRAM), and video RAM (VRAM). It provides details on the characteristics of SRAM and DRAM such as data volatility, refresh operations, cell structure, read/write speeds, cost, and applications.

1. Submitted by:
Md. Waresul Islam Shohan

2.  volatile memory
 stores frequently used program instructions
 increase the general speed of a system

3.  RAM stores its data in a series of memory
cells that can be accessed in any order, thus
why it is called Random.

4.  first form of RAM came
about in 1947.(CRT )
- by Fredrick Williams
 second widely used form
of RAM was magnetic-core
memory, invented in 1955
-by An Wang
 First mordernized form of RAM was released on 1969 by Intel.
A 32 x 32 core memory plane
storing 1024 bits of data.
cathode ray tubes as data storage

5. Close up view Normal view

8. 1.Static Random Access Memory (SRAM)
 Doesn’t need refreshing
 Retains contents as long as power applied to
the chip
 Access time around 10 nanoseconds
 Used for cache memory
 Also for date and time settings as powered by
small battery

9. 2. Dynamic Random Access Memory (DRAM)
 Contents are constantly refreshed 1000 times
per second
 Access time 60 – 70 nanoseconds

10. 3.Synchronous Dynamic Random Access
Memory (SDRAM)
 Quicker than DRAM
 Access time less than 60 nanoseconds
4. Direct Rambus Dynamic Random Access
Memory (DRDRAM)
 New type of RAM architecture
 Access time 20 times faster than DRAM
 More expensive

11. 5.Video Random Access memory (VRAM)
 Holds data to be displayed on computer
screen
 Has two data paths allowing READ and WRITE
to occur at the same time
 A graphics card may have its own VRAM chip
on board EXAMPLE: NVDIA

12. SRAM DRAM
 Data Volatility Y Y
 Data refresh Operation N required
 Cell structure 6T 1T - 1C
 Power consumption high/low high
 Read Speed (latency) ~10/70 ns ~50ns
 Write Speed ~5/40ns ~40ns
 Cost high low
 Power supply single single
 Application ex. Cache Memory Main Memory

13. Any Question ?