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Comments. Farnaz Moradi 2013. Construct a bulletin board system using Ensemble. Lab 1. Replies. RE:m1. A. m1. m2. B. m1. C. RE:m1. m2. Delivered by C:. RE:m1 must appear after m1 using a layer of ”Ensemble” .
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Comments Farnaz Moradi 2013
Replies RE:m1 A m1 m2 B m1 C RE:m1 m2 Delivered by C: RE:m1 must appear after m1 using a layer of ”Ensemble”. m2 is not caused by m1, so it doesn’t matter if it is delivered before m1.
Sending a Request for Old Messages m2 m3 m4 A B m1 Old Req m4 m3 C join m1,m2,m3 Duplicate! Delivered by C: m4 should be Delivered after old messages
Sending a Request for Old Messages m2 m3 Crash! A B m1 Req m4 m3 C join Messages queue in C: If the member from which we have requested the old messages crashes, what should C do?
Old Messages Sent by Leader m2 A Old m3 B m1 m3 join C m1,m2,m3 Delivered by C: Duplicate!
Old Messages Sent by Everyone m2 A Old m3 B m1 m3 Old m1,m2 join C m1,m2,m3 Duplicate! Delivered by C: Does the second ”Old” message replace the first ”Old” message or are they merged?
Old Messages Sent One by One m2 m3 Crash! A B m1 m2 m1 join C m4 If A crashes before it sends all the old messages to C, what should C deliver?