Draw a picture showing the connection between the processor and memory mapped IO devices Define the terms reliability dependability and availability Compare and contrast MTTF and AFR Explain the relationship between MTTF MTTR MTBF and availability ID: 713018
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Slide1
IO Introduction and Reliability
Draw a picture showing the connection between the processor and memory mapped IO devices.
Define the terms reliability, dependability, and availability
Compare and contrast MTTF and AFR.
Explain the relationship between MTTF, MTTR, MTBF, and availability.
Given MTTR and MTTF data, calculate availability.Slide2
Io Device Classifications
Behavior
Input, output, storage
PartnerHuman / MachineData RateThe peak rate at which data can be transferred from one device to another. Usually expressed in MBits per second (106, not 220)FYI: 220 =1,048,576
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What device has the highest data rate?
For each of the following
devices
:KeyboardScannerVideo CardCS2710 Computer Organization
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IO Device Diversity
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IO Device Interfacing: make devices “look” like memory
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Explain that reading and writing to a peripheral is merely like reading and writing to memory.Slide6
Laptop device information
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Dependability
The
quality of delivered service
such that reliance can be justifiably be placed on this service ReliabilityA measure of continuous service accomplishment, or the length of time to failure, from a given reference pointHow soon before it breaks?
Availability
A measure of service accomplishment with respect to the
alternation between states of accomplishment and states of
interruption
Uptime vs. Downtime
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More Definitions
Mean Time to
Failure (MTTF)
The average time it takes for a system to fail once startedMean time to repair (MTTR)The average time it takes to repair a failed systemMean time between failures (MTBF)The average time between system failuresCS2710 Computer Organization
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Availability
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Solve the following:
MSOE
is looking to replace its e-mail system. Two systems are being considered.
System 1 (Lookout*) has a mean time to failure of 99 hours and a mean time to repair of 1 hour. System 2 (Woogle*) has a mean time to failure of 9999
hours and a mean time to repair of .1 hours. Which system is more available? Which system would be the better
e-mail system
?
*names have been obfuscated to protect the guilty
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Where does failure matter? -
Hard Drives
ata
setType ofDuration#Disk
# ServersDisk
Disk
MTTF
Date of first
ARR
cluster
events
Count
Parameters
(Mhours)
Deploym
.
(%)
HPC1
HPC
08/01 - 05/06
474
765
2,318
18GB 10K SCSI
1.2
08/01
4.0
"
"
"
124
64
1,088
36GB 10K SCSI
1.2
"
2.2
HPC2
HPC
01/04 - 07/06
14
256
520
36GB 10K SCSI
1.2
12/011.1HPC3HPC12/05 - 11/061031,5323,064146GB 15K SCSI1.508/053.7"HPC12/05 - 11/064N/A14473GB 15K SCSI1.5"3.0"HPC12/05 - 08/06253N/A11,000250GB 7.2K SATA1.0"3.3HPC4Various09/03 - 08/06269N/A8,430250GB SATA1.009/032.2"HPC11/05 - 08/067N/A2,030500GB SATA1.011/050.5"clusters09/05 - 08/069N/A3,158400GB SATA1.009/050.8COM1Int. serv.May 200684N/A26,73410K SCSI1.020012.8COM2Int. serv.09/04 - 04/065069,23239,03915K SCSI1.220043.1COM3Int. serv.01/05 - 12/052N/A5610K FC1.2N/A3.6"""132N/A2,45010K FC1.2N/A5.4"""108N/A79610K FC1.2N/A13.6"""104N/A43210K FC1.2199824.1
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1.2 Million hours is approximately 136 years.Slide12
Failure Root Cause Analysis
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