vault backup: 2025-03-03 09:37:47

Concurrent Systems/notes/Lezione1.md

@@ -101,4 +101,14 @@ Deadlock freedom $\not{\implies}$ Starvation freedom
 	![[Pasted image 20250303093116.png]]
 
 Starvation freedom $not \implies$ Bounded bypass
-	Assume a $f$ and consider the scheduling above, where p2 wins $f(3)$ times and so does p3
+	Assume a $f$ and consider the scheduling above, where p2 wins $f(3)$ times and so does p3, then p1 looses (at least) $2f(3)$ times before winning.
+
+### Atomic R/W registers
+We will consider different computational models according to the available level of atomicity of the operations provided.
+
+Atomic R/W registers are storage units that can be accessed through two operations (READ and WRITE) such that
+1. Each invocation of an operation
+	- locks instantaneous (it can be depicted as a single point on the timelinethere exist $t : OpInv \to R+$)
+	- may be located in any point between its starting and ending time
+	- does not happen together with any other operation
+2. Every READ returns the closest preceeding value written in the register, or the initial value (if no WRITE has occurred).