Difference Between Static Ram and Dynamic Ram
RAM (Random Access Memory) is the primary memory used in computers. It is called random access memory because its cells can be accessed randomly. Static and dynamic RAM are the two categories of RAM. Transistors are used for the storage of data bits, these transistors does not need to be refreshed periodically. Static RAM (SRAM) uses transistors to store data bits and does not need to be periodically refreshed. DRAM uses different capacitors to store each data bit separately and must be periodically refreshed to maintain the charge in capacitors.
What is the Static RAM?
SRAM is a type of RAM and is a volatile memory that looses its data when power is switched off. In SRAM, every bit which saves data has 4 or 6transistors which create a flip-flop. There are additional transistors are used to control write and read right to access the storage cells. Although SRAMs typically use six transistors to store every bit, there SRAMs using eight, ten or more transistors to store a single chip. Reduction in number of transistors reduces the size of memory cells. SRAM cell is seen in three different states standby, read, write and replacement. When the data is requested, a cell is in ‘reading’ state, in ‘writing’ state when the data in the cell is changed and in the in the ‘standby ‘state when idle.
What is Dynamic RAM?
DRAM is a volatile memory that uses capacitors to store bits. The discharged capacitors represent 0 bit and charged ones represent 1. Since the capacitors fester over time, they must be refreshed periodically to maintain the values stored in them. Each memory cell in a DRAM consists of a capacitor and a transistor, and these cells are arranged in a square matrix. DRAMs are widely used for main memory in personal computers and game stations because they are cheaper. DRAMs are manufactured as integrated circuits (ICs) available in plastic packages with metal pins that might be connected to busses. Currently there are DRAMs in the market that are made as plug-in modules, which are easier to manipulate. The Dual In-line Memory Module (DIMM), Single In-line Pin Package (SIPP), and Single In-line Memory Module (SIMM) are examples of such modules.
What is the difference between the Static RAM and Dynamic RAM?
Although both SRAMs & DRAMs are versatile, these memories have some important differences. Since the DRAM requires a simple capacitor and a transistor for each memory cell is much simpler in structure than SRAM, which uses 6 transistors for every memory cell. On the other hand, due to the use of capacitors, the DRAM requires to be periodically refreshed as opposed to SRAM. The DRAMs are cheaper and slower than SRAMs. So they are used for large main memory of workstations, personal computers etc., while SRAM is used for the faster & smaller cache.