•Limitations of Distributed Systems
1.Absence of Global clock2.Absence of Shared Memory
How above are issues?
For instance assume there is Transaction happening. And there is no global lock or shared memory. In this case, if Money is deducted from Account-xyz 500$ and total balance was 5000$,And transferred Account ABC.
ACCOUNT XYZ-------------communication Channel----------> Account ABC
5000$ 0$
Divide above transfer process in 3 states
1) State of Account XYZ is recorded Before sending the Amount i.e 5000$
2) State of communication channel is recorded after Transferring 500$
3) State of Account ABC recorded before receiving Amount i.e 0$
In above scenario, The total amount produced 5000$ + 500$ =5500$.
Which is inconsistent. To overcome from above inconsistencies or issue, We have two approaches.
1) Lamports Logical clock
2) Vector Clock
https://www.youtube.com/watch?v=ELu_jVWqPNsFollow above link for understanding the Lamports clock and Vector Clock.
Casual Ordering of Messages
what is casual ordering of messages & Algorithm to implement the Ordering explained in below link.
BSS
SES
Matrix Algorithm
BSS
SES
Matrix Algorithm
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