vault backup: 2025-03-03 09:02:47

Concurrent Systems/notes/Lezione1.md

@@ -42,3 +42,22 @@ Different processes work to let all of them succeed in their task.
 	- only produced data can be consumed
 	- every datum can be consumed at most once
 
+#### Competition
+Different processes aim at executing some action, but only one of them succeeds.
+Usually, this is related to the access of the same shared resource.
+
+Example: two processes want to withdraw from a bank account.
+
+```js
+function withdraw() {
+	x := account.read();
+	if x ≥ 1M€ {
+		account.write(x – 1M€);
+	}
+}
+```
+
+While `read()` and `write()` may be considered as atomic, their sequential composition **is not**.
+
+![[Pasted image 20250303090135.png]]
+