Memory
Data and instructions are stored in memory to be executed. This memory is a temporary storage unit for data, instructions, and information. It is also called primary storage. It consists of one or more chips on the motherboard. The memory stores the following three items:
- Operating system and other system software to control the use of computer system.
- Application programs to perform specific tasks.
- Data to be processed by application programs.
The instructions and data is stored in memory as bytes during execution. Each byte in the memory has its unique address that identifies its location. There are two types of memory in the computer that are as follows:
Volatile Memory – Volatile memory loses its contents when the computer is turned off.
Non-Volatile Memory – It does not lose its contents when computer is turned off.
RAM
RAM stands for Random Access Memory. It is also called main memory or Direct Access Memory. Random access means that each individual byte in the entire memory is directly accessible. A program must be loaded into RAM before execution.
RAM is temporary memory. When the power is turned off, the information in this memory is lost. Thus it is called volatile memory.
RAM plays very important role in the processing speed of a computer. A bigger RAM size provides larger amount of space for processing. So the processing speed is increased. CPU can read data from RAM and write data to RAM. That is why RAM is also known as read/write memory. It is used to store data and instruction while it is being executed,
There are two types of RAM:
1. Static RAM
SRAM stands for Static Random Access Memory. The memory cells are made from digital gates. Each cell can store its value without any need to refresh the data as long as the power is available.
SRAM is more expensive. It does not need to be power-refreshed, CPU does not wait to access data. That is why it is faster. It utilizes more power than DRAM. It is normally used to build a very fast memory known as cache memory.
2. Dynamic RAM
DRAM stands for Dynamic Random Access Memory. It is a type of memory that is used in most computers. It is the least expensive kind of RAM.
DRAM requires an electric current to maintain its electrical state. The electrical charge of DRAM decreases with time that may result in loss of data. DRAM is recharged or refreshed again and again to maintain its data. The processor cannot access the data of DRAM when it is being refreshed. That is why it is slow.
Differences between SRAM and DRAM
The difference between SRAM and DRAM is as follows:
| SRAM | DRAM |
| It is faster than DRAM | It is slower than SRAM |
| It is more expensive. | It is less expensive. |
| It does not need to be power-refreshed. | It has to be refreshed after each read operation. |
| It utilizes less power. | It utilizes more power. |
