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

Design of structure chart, Design of structure chart - Standard qualit...

Design of structure chart - Standard quality structure charts result in programs that are modular, reusable and simple to execute. - Measures include: Cohesion

Explain naming convention scripts, Explanation:- A script within Rationa...

Explanation:- A script within Rational Robot is a file that haves a sequence of SQABasic code. The extension of the file is always ".REC". Syntax [FEATURE] + "_" + [FUNCTION

Explain salient points about indirect addressing, Q. Explain salient points...

Q. Explain salient points about indirect addressing? A number of salient points about this scheme are:  In this addressing scheme effective address EA and contents of th

What is a process scheduling, What is a Process Scheduling? Scheduling...

What is a Process Scheduling? Scheduling is a key element of the workload management software that usually performs several or all of: Queuing Scheduling Monito

Dick cheney approach, How many "true" terrorists are there in the US?  I do...

How many "true" terrorists are there in the US?  I don't know, but let's suppose that there are 3000 out of a total population of, say, 3,000,000.  That is, one person in 100,000 i

Hybrid model, The hybrid models are mostly tailormade models suiting to exa...

The hybrid models are mostly tailormade models suiting to exact applications. Actually these fall in the category of mixed models. Such type of application-oriented models keep cro

System requirements for chip design, The Peripheral interface chip system r...

The Peripheral interface chip system requires the construction of the interface chip circuit, which is controlled by main micro-controller via the user interface. I also need set

What is drive, Any data storage device. This having of  your CD-ROM drive, ...

Any data storage device. This having of  your CD-ROM drive, hard disk drive and floppy disk drive.

What is orbix?, Orbix is a CORBA ORB (Object Resource Broker) - a commercia...

Orbix is a CORBA ORB (Object Resource Broker) - a commercial software product which helps programmers builds distributed applications. Orbix is an execution of the OMG's (Object Ma

Difference between top-down and bottom-up programming, What is the differen...

What is the difference between top-down and bottom-up, programming? Ans: Top-down and Bottom-up Approaches In Top-down programming approach, we begin by identifying the main

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