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

What are grouping notations, What are Grouping Notations These notat...

What are Grouping Notations These notations are boxes into which a model could be decomposed. Their elements includes of packages, frameworks and subsystems.

Explain about cluster computing, The idea of clustering is defined as use o...

The idea of clustering is defined as use of multiple computers naturally multiple storage devices, PCs or UNIX workstations and their interconnections to make what emerges to users

Explain about hexadecimal numbers system, Q. Explain about Hexadecimal Numb...

Q. Explain about Hexadecimal Numbers system? Hexadecimal system has 16 digits that are represented as 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F. A number (F2) H is equivalent to

Define the term- encryption, Define the term- encryption The user would ...

Define the term- encryption The user would then type in O P E and card purchase will be authorised. This extra protection is used as well as encryption. Some of the new syste

Hashing, what is hashing in database management system?

what is hashing in database management system?

Explain working of d flip -flop, Q. Explain working of D Flip -Flop? D ...

Q. Explain working of D Flip -Flop? D (data) flip-flop is modification of RS flip-flop. Problem of undefined output in SR flip-flop when both R and S become 1 gets avoided in D

what is lrd_stmt?, The lrd_stmt function associates a character string (ge...

The lrd_stmt function associates a character string (generally a SQL statement) with a cursor. This function sets a SQL statement to be processed.

Declarative programming languages, Declarative programming languages: ...

Declarative programming languages: We notice that declarative programming languages can have some better compensation over procedural ones. Actually, it is often said that a J

Dbms, aggregation in dbms?

aggregation in dbms?

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