what is memory? also define its types.

A PC contains a chain of importance of memory gadgets for putting away information. They differ in their ability, speed and cost. Essential memory (likewise alluded to as the primary memory) is the memory that is specifically gotten to by the CPU to store and recover data. Optional memory (additionally alluded to as the outside or assistant memory) is a capacity gadget that is not available specifically by the CPU and utilized as a changeless stockpiling gadget that holds information even after the power is killed. 

types of memory in computer.
What is Primary Memory?
What is Secondary Memory?
Primary memory VS.   Secondary Memory

Essential memory is the memory that is straightforwardly gotten to by the CPU to store and recover data. More often than not, essential memory is likewise alluded to as the RAM (Random Access Memory). It is an unpredictable memory, which loses its information when the power is killed. Essential memory is specifically open by the CPU through the address and memory transport and it is always gotten to by the CPU to get information and directions. Besides, PCs contain a ROM (Read Only Memory), which holds guidelines that are executed frequently, for example, the startup program (BIOS). This is a non-unstable memory that holds its information when the power is killed. Since the principle memory is gotten too regularly, it should be quicker. Yet, they are littler in estimate and furthermore expensive.

Auxiliary memory is a capacity gadget that is not open straightforwardly by the CPU and utilized as a lasting stockpiling gadget that holds information even after power is killed. CPU gets to these gadgets through an information first moved in to the essential memory from the auxiliary memory before getting to. Typically, hard plate drives and optical stockpiling gadgets (CDs, DVDs) are utilized as auxiliary stockpiling gadgets in current PCs. In an optional stockpiling gadget, information is sorted out in to documents and registries as indicated by a record framework. This likewise permits to connect extra data with information, for example, the entrance authorizations, proprietor, last access time, and so forth. Besides, when the essential memory is topped off, optional memory is utilized as a brief stockpiling for keeping slightest utilized information in the essential memory. Optional memory gadgets are less expensive and bigger in measure. Be that as it may, they have a huge access time.

Essential memory is the memory that is specifically gotten to by the CPU to store and recover data, though the auxiliary memory is not available straightforwardly by the CPU. Essential memory is gotten to utilizing location and information transports by the CPU, while optional memory is gotten to utilizing input/yield channels. Essential memory does not hold information when the power is killed (unstable) while auxiliary memory holds information when the power is killed (non-unpredictable). Besides, essential memory is quick contrasted with the optional memory and has a lower get to time. However, essential memory gadgets are all the more expensive contrasted with optional memory gadgets. Because of this reason, for the most part a PC includes a littler essential memory and a considerably bigger auxiliary memory.