vault backup: 2025-03-10 09:04:43

Concurrent Systems/notes/3.md

@@ -115,5 +115,22 @@ A **MRSW Safe register** is a register that provides READ and WRITE such that:
 2. a READ that overlaps with a WRITE can return **any possible value** (of the register domain).
 
 A **MRMW Safe register** behaves like a MRSW safe register, when WRITE operations do not overlap. Otherwise, in case of overlapping WRITEs, the register can contain any value (of the register domain).
+*(Ci sta comunque lo stesso problema)*
 
-This is the weakest type of register that is useful in concurrency.
+> Si chiama safe nel senso che se ci sono letture overlapping siamo safe. Ma è letteralmente l'unica cosa safe che abbiamo!
+
+This is the weakest type of register that is useful in concurrency.
+
+### Bakery Algorithm
+**The idea is that**
+- every process gets a ticket
+- because we don't have atomicity, tickets may be not unique
+- tickets can be made unique by pairing them with the process ID
+- the smallest ticket (seen as a pair) grants the access to the CS
+
+```
+Initialize FLAG[i] to down and MY_TURN[i] to 0, for all i
+
+lock(i) :=
+	FLAG[i] <- up
+	MY_TURN[i] <- M