Based on NIELIT, BY Impulse Technology
The function of the memory or primary memory is to store data an information that is currently running in computer. It is essential component of the computer system..
There are two types of Main memory..
This type of memory contains data and instruction Only for the time that the computer is switch on, as soon as it switch off the main memory losses it contain . example RAM, CACHE.
RAM is a read/writes memory(volatile memory), Data and instruction can be read and write from Ram .RAM is the hardware, that is generally located on the motherboard, and is use to execute the operating system (OS), application programs and data in current use and are kept into RAM so they can be quickly reached by the device's processor..
SRAM can written store information as long as the power supply is on. SRAM is costly and consume more power to store data.They do not need refreshing circuit and higher speed than Dynamic RAM..
DRAM stores each bit of data on a separate capacitor for very sort time, even when power supply is on therefore, DRAM have to be refresh periodically, generally 2 millisecond and have higher packing density with moderate speed and consume less power & used where a large capacity is memory .`
Cache memory is placed between the CPU & the main memory, it is faster than the main memory (RAM). Hence Access time is much less than that of memory .The access time of cache memory is 15-25 nanosecond where as that of main memory 80 nanosecond the cache memory store instruction and data which are to be immediately executed .It is to reduce average access time. The information frequently required by the processer is available in the cache memory .
The Size of the L1 cache very small as comparison to others(L2 or L3) that is between 2KB to 64KB, It is built into actual computer processor core. It is a embedded register in the computer microprocessor(CPU).The Instructions that are required by the CPU that are firstly searched in L1 Cache. Example of registers are accumulator, address register,, Program counter etc.
The Size of the L2 cache is more capacious than L1 cache.It is placed between the CPU and RAM.`
The Size of the L3 cache is more capacious than L1 and L2, it's size is between 1MB to 8MB, and is used in special computer like servers etc.
This(NVM) is a type of computer memory that has the capability to hold saved data even if the power is turned off.
Rom is parmanent type of memory it contain are not loss even power supply is off. However the user can not writeinto the rom. It contain are written into the manufacturingtime. Rom store parmanent program and other type of data which are needed by the computer to execute user program.
Prom stand for programmable read only memory . prom are also available onces program. Prom the information writen by user can not be change such information is needed while executive program.
EPROM stand for Eraseable Progammable Read Only Memory.the store data in Eprom can be erased by exposing them to high intensity short way ultravoilate. .
EEPROM stand for Electrical Eraseable Programmable Read Only Memory.EEprom is a rom that can be erased and reprogram using electrical charge..