What is Random Access Memory (RAM) and Types of RAM's

RAM stands for Random Access Memory. It is also known as read/write memory, main memory and primary memory. RAM is a temporary memory it stores data temporarily and once the power is switched off, the information in the RAM is lost. Information that is stored permanently is written to the hard drive. So RAM is known as volatile memory. Volatile means the information is lost when the computer is switched off or when power fails. RAM is measured in kilobytes (or) Megabytes (or) Gigabytes.


RAM is mainly Three types:
1. Static Ram (SRAM)
2. Dynamic Ram (DRAM)
3. Cache Memory


Static Ram:
This is Ram provides a static storage of data. It is fast, has lower access time and Expensive.

Dynamic Ram:
This is computer memory, that losses its memory capability once the power source is removed. It is slower, has higher access time than SRAM. Dynamic Ram cheaper than SRAM.

Cache Memory:
It is very high speed memory that is much faster than primary memory. This cache memory is faster but more expensive to have bigger size of cache memory and its size is normally small.  Data is transferred automatically between the buffer and primary storage. Cache memories are accessed much faster than conventional RAM.

Different Types of RAM Memory :

Measuring Unit of Computer:
Bit : Stands for binary digit. 0 or 1 is called a bit (1 means ON, 0 means OFF). A 'bit' is the smallest memory unit of a computer.
Byte : Stands for 8 binary digits a group of 8 bits equal to 1 byte

Term Definition :
Kb - Kilobit
KB - Kilobyte
Mb - Megabit
MB - Megabyte
Gb – Gigabit
GB - Gigabyte
Tb - Terabit
TB - Terabyte

Measuring Memory: 

K, Kb, KB :

K (Kilo, thousand) Kb (Kilobit) one thousand bits

KB (Kilobyte) one thousand bytes

1 KB equal to 1,024 bytes or 2¹⁰ bytes

M, Mb, MB :

M (Mega, million) 

Mb (Megabit) one million bits

MB (Megabyte) one million bytes

1 MB equal to 1,048,576 bytes or 2²⁰ bytes

G, Gb, GB :

G (Giga, billion) 

Gb (Gigabit) one billion bits

GB (Gigabyte) one billion bytes

1GB equal to 1,073,741,824 bytes or 2³⁰ bytes

T, Tb, TB :

T (Tera, trillion) 

Tb (Terabit) one trillion bits

TB (Terabyte) one trillion bytes

1 TB equal to 1,099,511,627,776 bytes or 2⁴⁰ bytes

RAM Types and Definition: 
SIMM - Single Inline Memory Module
DIMM - Dual Inline Memory Module
SO-DIMM - Small Outline Dual Inline Memory Module
RIMM - Rambus Inline Memory Module
SO-RIMM - Small Outline Rambus Inline Memory Module
SRAM - Static Random Access Memory
SDR - Single Data Rate
RDRAM - Rambus Dynamic Random Access Memory
DDR - Double Data Rate
DRAM - Dynamic Random Access Memory or Module
SDRAM - Synchronous Dynamic Random Access Memory
DDR-SDRAM - Double Data Rate Synchronous Dynamic Random Access Memory