Look Ahead buffer vs Translation Look aside buffer

Problem Detail: 

I know that Translation look aside buffer is used for address translation in paging to achieve better performance.

I came across term called Look Ahead buffer in a document which said it implements Temporal locality.

I tried searching for Look Ahead buffer's but could not get any significant data.

Please help

Asked By : eshi14

Answered By : RDN

I do not know the exact definitions of TLBs and look-ahead buffers, but here is what I understand about them.

TLBs help make translations from virtual to physical addresses quicker via caching. So, you can see how the TLB is implementing temporal locality (any kind of caching is implementing temporal locality) in some sense.

Look ahead buffers on the other hand come into play when while bringing data from disk to memory. Pages that are explicitly requested may be brought into the disk buffer along with other pages (often selected based on spatial locality to the requested page -- but there are other heuristics that the disk can use). The idea is to not have to go to disk too often. Instead the disk will try to predict what pages will be required in the RAM in the future (hence the term "look-ahead").

Note: I have heard people call the TLB the look-aside buffer and the look-ahead buffer. To me it seems like "translation look-aside buffer" is the correct expansion (because I dont see where any "looking ahead" is happening).

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Question Source : http://cs.stackexchange.com/questions/9612