Major problems associated in writing with cache memories, Computer Engineering

Assignment Help:

Q. Major problems associated in writing with cache memories?

The data in main and cache memory can be written by processors or I/O devices. The major problems associated in writing with cache memories are:

a) The contents of cache and main memory can be changed by more than one device. For illustration CPU can write to caches and I/O module can directly write to main memory. This can result in inconsistency in values of main and cache memory.

b) In case of multiple CPUs with different cache a word changed in one cache automatically invalidates that specific word in other cache as well.

The proposed schemes for writing in system with caches are:

(a) Write through: Write the data in main memory as well as cache memory. The other CPUs - Cache combination has to watch with traffic to main memory and make appropriate modification in contents of cache. The drawback of this scheme is that a bottleneck is created because of large number of accesses to main memory by different CPUs.

 (b) Write block: In this technique updates are made only in cache, setting a bit known as Update bit. Only those blocks whose update bit is set is replaced in main memory. However here all accesses to main memory whether from other CPUs or I/O modules required from cache resulting in complex circuitry. 

 (c) Instruction Cache: An instruction cache is one that is used for accessing only instructions and nothing else. Benefit of such a cache is that as instructions don't change we do not need to write instruction cache back to memory unlike data storage cache.


Related Discussions:- Major problems associated in writing with cache memories

Multiple assign statements targeting the same wire, What logic is inferred ...

What logic is inferred when there are multiple assign statements targeting the same wire? It's illegal to specify multiple assign statements to the same wire in a synthesizable

The concept of parallel execution and concurrent , The Concept of Parallel ...

The Concept of Parallel Execution and Concurrent Real world systems are obviously concurrent, and computer science is about modelling the actual world. Examples of actual worl

Input output techniques - computer architecture, Input Output Techniques: ...

Input Output Techniques: o   Interrupt driven o   Direct Memory Access (DMA) o   Programmed Programmed I/O   CPU has control over I/O directly   Read/write

Describe the term- system analyst design, Describe the term- System analyst...

Describe the term- System analyst Design Once analysis has taken place and systems analyst has some idea of the scale of problem and what needs to be done, subsequent stage is

What is the purpose of iop, What is the purpose of IOP. The purpose of ...

What is the purpose of IOP. The purpose of IOP is to given an independent path way for transfer of information among external and internal memory.

What is the syntax of the assembler directive equ, The syntax of the assemb...

The syntax of the assembler directive EQU is ? Ans. The syntax of the assembler directive EQU is as given below: EQU

Show the properties of frame tag, Q. Show the properties of Frame Tag? ...

Q. Show the properties of Frame Tag? This tag is used for placing an HTML file in the frame created. We should now tell browser what to put in every frame.

Describe about javascript, World Wide Web (WWW) began as a text-only medium...

World Wide Web (WWW) began as a text-only medium. First version doesn't even have the capability to include graphics on a page. Today's Web sites include sound animation, graphics,

Learning decision trees using id3 - artificial intelligence, L e arning D...

L e arning Decision Trees Using ID3 Sp eci f y i n g the Problem We now have to look at how you mentally created your decision tree when deciding what to do at

Fundamental functional units of a computer, Fundamental functional units of...

Fundamental functional units of a computer: QUE. What are the fundamental functional units of a computer? Ans: A computer consists of 5 functionally independent major parts

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd