Virtual Memory

Question

 

Comments

in CO, you can get better clarity about this...

Order of Memory accessing :-

Registers, Cache, Main Memory, Secondary Memory, then Magnatic Tapes, Magnatic Disks.

TLB is one more memory which is introduced between Registers and Cache

 

option B is correct

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where u got that first it use disk then magnetic tape and magnetic disk?

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mam, disk means secondary Memory ? if yes,

r u agreeing that size of disk < size of magnetic tapes

then access time of disk should be less than access time of magnetic tapes

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Actually magnetic tape and magnetic disk are example of secondary memory . And access time of magnetic   disk has faster access time than magnetic tape

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Hold on my thinking :-

When a logical address is generated it is indexed into TLB. If miss then we access main memory first for getting the frame after then we access cache to check wether that page is there or not if cache miss then we get the penalty for accessing the cache so we again go to main memory and directly get to the page.

So

TLB MISS --> MAIN MEMORY --> CACHE MISS --> MAIN MEMORY.

Correct me ??

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Because how after tlb miss i can directly access cache for indexing i need frame number first then i can check wether the page is there or not right ?

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Cache itself is a small fast memory. That is why after TLB miss we directly access cache. No need to go main memory then

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Actually files reside in Secondary Memory (Disk)

part of files(pages) reside in Main Memory

part of Pages ( Blocks ) reside in Cache

part of Blocks ( words ) reside in TLB

 

logical address generates a address for a word ===> check in TLB, if miss ===> check in cache, if miss ===> check in Main Memory, if miss =====> check in Secondary Memory.

Real life Example:-

You required spare part of your Bike.

you ask mechanic, if he doesn't contain ----> go to the showroom in your town, if there also not present ----> Go to showroom in Capital of State,if there also not present ----> Go to showroom in Capital of Nation.

you can't go directly to the showroom in Capital of Nation if Mechanic doesn't have it.

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Mam if there is TLB Miss i wont have frame number then how i will address the cache ? Untill its a logical cache else please tell how you will address the cache ?

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Please Explain here anybody :(

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TLB Miss

If we don't find the page frame number inside the TLB, it is called a TLB miss only then we go to the page table to look for the corresponding page frame number.

 

Now where page table stored in?

Most modern systems provide some hardware acceleration for translating page addresses, and maintain an on-chip cache of translations (the TLB, or translation lookaside buffer). This table is not the page table, but is a cache for recently used page table entries. 

so in case of TLB miss just access the cache.

Got the point?

For more https://stackoverflow.com/questions/37825859/cache-miss-a-tlb-miss-and-page-fault/37827756

https://www.quora.com/Where-in-the-computer-architecture-is-the-page-table-stored-in 

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Ans D)

Answer 1

TLB---->Cache mem---->main mem.