Showing posts with label time. Show all posts
Showing posts with label time. Show all posts

Thursday, January 5, 2023

Mean Time Failure and other Formulas

Important formula for Mean Time Failures




MTTF - Mean Time To Failure
 MTTF = 1 / failure rate = Total #hours of operation / Total #units
 MTTF is an averaged value. In reality failure rate changes over time
because it may depend on age of component.

 Failure rate = 1 / MTTF (assuming average value over time)

 MTTR - Mean Time to Recovery / Repair
 MTTR = Total #hours for maintenance / Total #repairs

 MTTD - Mean Time to Diagnose

 MTBF - Mean Time Between Failures
 MTBF = MTTD + MTTR + MTTF


MTTF - Serial assembly 

 MTTF of system = 1 / SUM (1/MTTFi) for all components i
 Failure rate of system = SUM(1/MTTFi) for all components i

MTTF - Parallel assembly 

MTTF of system = SUM(MTTFi) for all components i

 Availability = Time system is UP and accessible / Total time observed

 Availability = MTTF / (MTTD* + MTTR + MTTF)
or
 Availability = MTTF / MTBF

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Wednesday, January 4, 2023

Cache performance and Access time of memories

• Cache hit
✓ When CPU refers to memory and find the data or instruction within the Cache Memory
• Cache miss
✓ If the desired data or instruction is not found in the cache memory and CPU refers to the
main memory to find that data or instruction
Hit + Miss = Total CPU Reference
Hit Ratio h = Hit / ( Hit + Miss )

Average access time of any memory system consists of two levels:
✓ Cache Memory
✓ Main Memory
• If Tc is time to access cache memory and Tm is the time to access main
memory and h is the cache hit ration, then
Tavg = Average time to access memory
Tavg = h * Tc + ( 1-h ) * ( Tm + Tc )

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All the messages below are just forwarded messages if some one feels hurt about it please add your comments we will remove the post.
Host/author is not responsible for these posts.

Wednesday, July 1, 2009

increasing the logout time in websphere admin console

If you are using WebSphere Network Deployment (and you should be) edit this attribute in the following file on the Network Deployment machine:C:\Program Files\IBM\WebSphere\AppServer\profiles\Dmgr01\config\cells\NetworkDeploymentservernameCell01\applications\isclite.ear\deployments\isclite\deployment.xmlSet the attribute invalidationTimeout to the desired value, in minutes, where the maximum value is -1 (do not time out)

Wednesday, February 4, 2009

Bad times for Raju community...


Bad time for Raju community is going on...It was Siris Raju, Nagarjuna Finance Ltd., KS Raju and then followed by Satyam Computer Services Ltd Ramalinga Raju.


While KS Raju was caught by police,Ramalinga Raju confessed the fraud.
Companies started by Rajus raise to fame before they fall .

But both these rajus were in heights before the scams came over.Both are caught in financial matters only.




God save Raju community.All Rajus do good before they fall prey of some other people.