VOLATILE MEMORY.

There are two types of semiconductor memory, volatile and non-volatile memory.

here is blog on VOLATILE MEMORY.

What is volatile memory?

Volatile memory is the kind of computer memory that requires power to maintain the stored information. Volatile memories are those memories that store the data temporarily. More specifically we can also say that data is stored in volatile memory is only up to the duration until power supply to the IC is ON. And once the supply gets OFF then the information (data) stored gets lost. However volatile memory can be faster and less expensive than non-volatile memory. This type of memory is used as the main memory in most of the computers, since data is stored on the hard disk while the computer is off.

Major types of volatile memories are RAM (see SRAM) or dynamic RAM (see DRAM).

RAM – Random Access Memory: RAM or (random access memory) is a form of semiconductor memory technology that is used for reading and writing data in any order – in other words as it is required by the processor. RAM is a form of computer memory that can be read and changed in any order, typically used to store working data and machine code. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory.
Random access memory is used in huge quantities in computer applications as current day computing and processing technology requires large amounts of memory to enable them to handle the memory hungry applications used today. Many types of RAM including SDRAM with its DDR3, DDR4, and soon DDR5 variants are used in huge quantities.

RAM is majorly classified into two categories:

SRAM
DRAM

SRAM: It is an abbreviation for Static Random Access Memory. SRAM has an array of flip-flops that are used to store the data. The memory cells consist of flip flops that hold the data until the power supply is on.It means to store data in SRAM remains active as long as the computer system has a power supply. However, data is lost in SRAM when power failures have occurred.

Characteristics of Static Ram

It does not require to refresh.
It is faster than DRAM
It is expensive.
High power consumption
Longer life
Large size
Uses as a cache memory

DRAM: (Dynamic Random Access Memory). In DRAM each cell carries one-bit information. The cell is made up of two parts: a capacitor and a transistor. The size of the capacitor and the transistor is so small, requiring millions of them to store on a single chip. Hence, a DRAM chip can hold more data than an SRAM chip of the same size. However, the capacitor needs to be continuously refreshed to retain information because DRAM is volatile. If the power is switched off, the data store in memory is lost. It is also a read/write memory that stores the data in the form of charges in the capacitor and transistor pair present in the memory cell.

Characteristics of DRAM

It requires continuously refreshed to retain the data.
It is slower than SRAM
It holds a large amount of data
It is the combination of capacitor and transistor
It is less expensive as compared to SRAM
Less power consumption

DRAM and its Types

In short, DRAM is a one of several types of RAM that are commonly used. All DRAM is RAM, but not all RAM is DRAM.

Synchronous DRAM (SDRAM) syncs memory speeds with CPU clock speeds, letting the memory controller know the CPU clock cycle. This allows the CPU to perform more instructions at a time.
Rambus DRAM (RDRAM) was more widely used in the early 2000s for graphics cards.
Double Data Rate SDRAM (DDR SDRAM) almost doubles the bandwidth in data rate of SDRAM by using double pinning. This process allows for data to transfer on rising and falling edges of a clock signal. It has been available in different iterations over time, including DDR2 SDRAM, DDR3 SDRAM and DDR4 SDRAM.
Fast page mode DRAM (FPM DRAM) gives higher performance than other DRAM types through focusing on fast page access.
Extended data out DRAM (EDO DRAM) improves the time to read from memory on microprocessors, such as the Intel Pentium.