vault backup: 2025-04-01 09:14:49

Concurrent Systems/notes/10 - Consensus Implementation.md

@@ -64,3 +64,20 @@ p(C’) can be R1.read() or R1.write(v) and q(C’) can be R2.read() or R2.write
 4. R1 = R2 and both operations are a write
 	- *Remark:* q(p(C)) = q(C) cannot be distinguished by q since the value written by p is lost after the write of q
 	- Then, work like in case (3).
+
+### CN(Test&set) = 2
+```
+TS a test&set object init at 0
+PROP array of proposals, init at whatever
+
+propose(i, v) :=
+	PROP[i] <- v
+	if TS.test&set() = 0 then
+		return PROP[i]
+	else
+		return PROP[1-i]
+```
+Wait-freedom, Validity and Integrity hold by construction.
+
+Agreement: the first that performs test&set receives 0 and decides his proposal; the other one receives 1 and decides the other proposal.
+