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

Explain the virtual memory, What is virtual memory?  Virtual memory is ...

What is virtual memory?  Virtual memory is a technique that permits the execution of processes that may not be completely in memory. It is the separation of user logical memory

Define the meaning of document and finger print, a. Define the meaning of "...

a. Define the meaning of "Document & Finger print" and "Message & Message Digest". What's the difference among the 2 pairs? b. Describe Davies Meyer scheme with diagram. c. W

What is an compiled languages, What is an compiled languages In compile...

What is an compiled languages In compiled languages the instructions into machine code and kept them  in a separate file for later implementation. Many modern compilers can com

Explain application and system software, Fundamentals of IT 1. Explain ...

Fundamentals of IT 1. Explain the Impact of Information Technology on governments and educational organizations. 2. Explain application and system software. 3. Briefly ex

Explain multithreading in a programming language, Multithreading is the pro...

Multithreading is the process in which more than single thread run independent of each other within the process in any programming language such as C, C++, etc.

Difference between static and dynamic RAM, Difference between static and dy...

Difference between static and dynamic RAM. Draw the circuits of one cell of each and explain its working. Ans: Differentiation among Static RAM and Dynamic RAM: Static

Information security, i wants to know the methods and process of substituti...

i wants to know the methods and process of substitution and transposition cipher with examples.

Concepts of evolution are used by the genetic algorithm, Q. What basic conc...

Q. What basic concepts of evolution are used by the genetic algorithm? ANSWER: The three concepts are selection, crossover and mutation. Selection is the feature of a genetic a

Define a formal system, Q. Define a Formal System? A Formal System is o...

Q. Define a Formal System? A Formal System is one which is planned in advance and is used according to schedule. In this system procedures and policies are documented well in a

Define process for swapping into memory from the swap device, What are the ...

What are the criteria for choosing a process for swapping into memory from the swap device? The resident time of the processes in the change device, the priority of the process

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