Primary memory is a memory board that's accessed directly by the C.P.U.. each pc has such a cupboard space that is understood as primary storage.

It is a brief hold, that is made within the component. the first storage is made within the C.P.U. of the pc system.

Physically, primary memory consists of some chips either on the motherboard or on a tiny low board connected to the motherboard of an ADP system.

Primary memory or main memory is of four types:-
1. RAM
2. ROM
3. Cache memory
4. nonvolatile storage

         



1.  RAM

A RAM stands for Random Access Memory. A RAM is that the internal memory of the C.P.U. for storing information, programs, and program results. it's read/write memory. it's additionally referred to as Random Access Memory (RAM). we are able to touch the memory randomly and intensely quick however can even be quite dear.

RAM is volatile, information keep in it's lost once we turn off the pc or if there's an influence failure. thence a break-up UPS is usually used with computers. and also the backup UPS is extremely vital for the U.S.A. as a result of if we tend to do some vital work on the pc and power association is out then we tend to lost our all information at intervals a second.

RAM ( Random Access Memory ) is little in each group of its physical size and within the quantity of knowledge, it will hold. RAM comes within the variety of ' distinct ' microchips and additionally within the variety of modules that plugs into holes within the pc motherboard. These holes connect through a group of electrical ways to the processor.




  • DYNAMIC RAM 
DRAM may be a common kind of random access memory (RAM) that's employed in personal computers (PCs), workstations, and servers. Random access permits the laptop processor to access any part of the memory directly instead of having to proceed consecutively from a root. RAM is found on the point of a computer's processor and permits quick access to information than storage media like hard disc drives and solid-state drives.

  • STATIC RAM
Static random-access memory (static RAM or SRAM) may be a kind of random-access memory (RAM) that uses latching electronic equipment (flip-flop) to store every bit. SRAM may be a volatile memory; information is lost once power is removed.

The term static differentiates SRAM from DRAM (dynamic random-access memory) that should be sporadically fresh. SRAM is quicker and costlier than DRAM; it's generally used for C.P.U. cache whereas DRAM is employed for a computer's main memory.




Some of the benefits of RAM are:–


It will increase the pc system speed, and also the higher the system speed, the bigger the RAM.
The C.P.U. will browse information faster than the RAM. (Compared to a hard disc, CD, DVD, FLOPPY, DISK, and USB)
There is little use of battery life.
It will write and delete operations.
Some of the disadvantages of RAM are:–

If the C.P.U. needs to browse the information from the RAM, then the information accessible from the registers and also the cache is slow compared
RAM is volatile, i.e. it's troublesome to store information forever.
It is dear.
It has a restricted area.



2.  ROM

The memory from that we are able to solely scan however cannot write it. These are non-volatile. computer memory also can be accustomed to store that software package that is usually required by the pc. The program keeps on computer memory ( scan solely Memory ) is named computer code. alternative terms used for computer code ar firmware and microprogram.
computer memory ( scan solely Memory ) is additionally divided into 3 sorts promenade, EPROM, and EEPROM.

  • PROM ( Programming Read-Only Memory )

promenade stands for programming storage. promenade maybe storage which will be changed just once by a user. The user buys a blank promenade and enters the specified content exploitation of the promenade technologist. It will be programmed just once and isn't eradicable.

So, the promenade is additionally referred to as just one occasion programmable ( OTP ) device. The blank promenade is economical. promenade chips are valuable for firms and that they forever use promenade as a result of once they modification their code while not requiring overpriced instrumentality.



  • read-only storage (Erasable and Programmable storage )


read-only storage stands for eradicable and Programmable storage.
An read-only storage ( eradicable and Programmable storage ) and reprogramme or enter new information. however in read-only storage it will erase all information gift.
read-only storage isn't able to implement a specific a part of the information.EPROM is costlier than the promenade.EPROM ( eradicable and Programmable storage ) is sometimes employed in software package development and software package testing processes.
  • EEPROM ( Electrically eradicable and Programmable storage )
EEPROM stands for Electrically eradicable and Programmable storage. EEPROM will be erased and reprogrammed regarding ten,000 times. In EEPROM each erased and programmed take regarding four to ten ms ( time unit ).
In EEPROM {we can|we will|we are able to} able to erase a specific a part of all information gift. In EEPROM the method of re-programming is versatile however slow.

Some of the benefits of computer memory ar –

  • It is non-volatile and is cheaper than RAM
  • As they're static they are doing not would like refreshing each time.
  • Circuits are straightforward and computer memory is additional reliable than RAM.
  • Data will be kept for good
  • It helps to start out the pc and hundreds the OS.

Some of the disadvantages of computer memory ar –

  • ROM is read-only, can not be changed.
  • If changes are needed, it's inconceivable.

3.  CACHE  MEMORY

Cache memory is that the quickest system memory needed to stay up with the electronic equipment because it fetches and executes directions. the information most often utilized by the electronic equipment is kept in cache memory. The quickest portion of the electronic equipment cache is that the register file, that contains multiple registers. Registers ar little storage locations utilized by the electronic equipment to store directions and information.

4.  FLASH MEMORY 

Cache memory is a particularly quick memory sort that acts as a buffer between RAM and therefore the electronic equipment. It holds often requested information and directions so they're right away out there to the electronic equipment once required. Cache memory is employed to cut back the typical time to access information from the most memory.

non-volatile storage may be a chip used for storage and for transferring information between a private pc (Pc) and digital devices. they're quicker than mechanical disks. non-volatile storage chip may be a special variety of EEPROM. non-volatile storage is eradicable and re-programmable. In non-volatile storage, the complete device is erased in one operation

Advantages of flash memory:-
  • Non-volatile
  • Small size
  • Fast
  • Very low energy consumption
  • Portability
  • Fast Transfer Speeds
    Disadvantages of flash memory:-
    • Most flash drives don't have have a write-protection mechanism
    • Smaller size devices, like flash drives, create them easier to lose
    • Currently prices a great deal additional per GB than ancient onerous drives for giant storage capacities.
    • The primary disadvantage of non-volatile storage is that the worth and rewrite limitations.
    • There is a finite variety of times info will be erased and written to the memory stick.