why we use primary memory is less than compare to secondary memory ?

Answer 1

Put simply it all comes down to cost. Much faster memory sources, such as the CPU cache, are far more expensive per byte, thus the requirement for an overflow to lower cost, higher capacity memory sources.

Answer 2

The main answer for this Q is that primary memory is very very costly.
Secondly and the primary memory is volatile so it doesnt make any sence storing data in such king of memory.
Also to tell u when u run or execute a program it starts running in the memory.
But only the required part of the program gets the place in the memory and the other part(also called as a thread of the program) is in the virtual memory waiting to come in as and when it is required.The virtual memory is nothing but a small place on ur secondary memory and is betwn secondary and primary memory.
The reason is bcoz data from the Secondary memory such as HDD's CD's cannot directly go to the Primary memory.
So they are first stored in the virtual memory and then used as and when required.
E.G:to give u and example
If u run a program which is 300Mb and ur have just 256 Mb of RAM how does the program run?

Ans:Its bcoz only a part of the program is given place in the Primary memory and when some other part the program is needed to be executed the one which is not used is swapped out on the virtual memory.
This is how the CPU makes efficient use of ur Primary memory.

No doubt a larger primary memory will increase the speed of ur computer but also cost u big bucks.

I guess this would explain u a bit.
Wat do u say?
Regards
Taral

Answer 3

I b elieve you are asking why the primary memory (that on the mircoprocessor) is smaller than the secondary memory (the RAM chips).

The RAM chips hold all the programs you are running, any open data files, and Windows itself. That can be a lot of stuff, so it needs a lot of memory. But most of the things in the RAM memory are not being actived processed. If you have a 20 page document loaded, you can only edit one page of it at a time. The other 19 are just setting there doing nothing.

The primary memory, on the microprocessor, is where most of the real "work" happens. It is were you need the one page you are editing or the instructions you are currently running. It does not need to see the 19 pages you are not currently editing.

In fact, if you were to load all 20 pages and then switch to doing something else, the porcessor would have to stop and unload all twenty pages before it could load the next program. If you switched back it would have to reload all 20 pages. It is faster for the primary memory to be smaller and only hold the things you are actually working on at the moment. It has to be larger enough to hold the things you are actually processing, but no so large that it gets filled up with junk.

So the secondary memory, used to hold things that are not being actively processed, should always be larger then the primary memory, which holds the active items.

Answer 4

i assume that primary memory is the RAM and secondary is the hard disk that peripheral storage devises.
firstly,primary memory is used to execute the programs n store the intermediate results so it has to be faster,so an expansive tech. is used ,also this is volatile so data cant be stored parmanently n here comes secondary memory which stores a large amount of data also the progaram which r not currently in used..
ok so the primary is used for current processing so a small but considerable size is required for greater speed ,also in many real time application n arithemetic calculation,Even ram is considered too long so cache memory is used
So speed n cost r the cause which make primary memory size less,also we have no use of a large amount of primary becoz it not going to store any data pamanently It just needed for current processing

Answer 5

Your question is not clear, and I don't know what you mean by secondary memory. Primary memory is the total memory in your computer, less the amount of ram memory set aside for graphics and video. It is called Total Physical Memory. Available physical memory is that memory that is not currently being used by the computer.

Answer 6

.

First of all everybody make it clear that

Primary Memory is "RAM", which is present in the board itself.
Secondary Memory is "Disk", which is a pheripheral device.

You know that RAM is faster than hard disk and so we are using it as the main memory for performing operations and hard disks are just used to store data.

The access time of RAM is around 5 nano seconds, but access time of Hard disk is around 10 milli seconds.

As you know when ever a product is very good then the price will also be very high. The price of RAM (Primary memory) is very high than that of Secondary memory. And hence it used less.

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Vasu M
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Answer 7

Pleas explain your question. Primary memory and secondary memory of what?(ram, cpu).

Answer 8

primary memory and secondary memory of what ?(ram, cpu)

Answer 9

At first we can discuss about memory .All microprocessor based processor has mainly five type of memory.
1.Very local memory --- "registers" ,this type of memory is implemented in the chip and mpu can access this memory at single
clock cycle.It's cost is highest because it is made with flip-flop (normally "d flip-flop" and "tri-state buffer").
2.Local memory --- "cache memory" , when mpu(microprocessor unit) can not find the instruction or data ,then it goes to cache and find there (there are three type of cache L1,L2,L3).It is very very costly .It is smallest according to size without considering registers.
3.Primary memory --- "RAM - random access memory".Be care-full, from here your answer is start.When mpu occurs a "miss", means that if it does not find data at cache ,then it comes here and it is the last place where a mpu can access.Just for this reason, the data transfer speed should be much fast enough.So some portion of it made with ram - chip and else part is made with rom - chip, depending upon the architecture.Now the total chip can be made with sdram or rdram .The data transfer speed and block(some time referred as frame) access speed of sdram is much better than rdram.But sdram is very costly.But overall gain of rdram is economical - so we generally used rdram in desktop computer (In an IBM mainframe pc ,they used a primary storage totally made with sdram .....). In any case of ram, each cell of it is build with many flip-flop, magnetic core and transistors. It will be synchronised or asynchronous with cpu-colck.The cost of cmos(complementary metal-oxide semiconductor) transistor or normal (n/p) transistor(note:- transistor is made of silicon/germanium which is costly) , flip-flop (or latch) and clock is costly, so overall cost is increase.And so total size of it will be small compare to secondary storage.
4.Secondary memory --- "Hard disk , magnetic tape etc." This type of storage is made with magnet.In the case of hard-disk,it contains mainly a device driver, a device queue, a little cache and few no. of circular magnetic disks (platter) (with read/write head associated with disk arm ) with a spindle which attach with a device motor.So the main cost is of magnet , and believe me it is very cheaper than sd/rd-ram.In the case of tape, there are exists magnetic rill, head and two spindle.So, overall manufacturing cost is less than primary storage.And so vendors can provide larger size.
5.Tertiary memory --- ( ISO 9660 CD/DVD ROM, flash memory based pen/USB drive etc.) [Don't consider virtual memory , it is mainly a part of your hard disk ...]

According to above all, we "use" less primary memory than secondary memory.But according to computer architecture and memory uses we can be classified them as register>cache>primary memry>(virtual memory>)secondary memory>tartiary memory.Without considering cache and register, if the cost of secondary storage is less than primary storage ,then we must want to use huge primary storage and a little secondary storage (for back-up) forever ,because in that case system performance will increase rapidly and will be 60 times better...