vault backup: 2025-03-25 12:47:48

.obsidian/workspace.json

@@ -43,6 +43,18 @@
         "type": "tabs",
         "dimension": 57.23495702005731,
         "children": [
+          {
+            "id": "b307be81cd26d1cb",
+            "type": "leaf",
+            "state": {
+              "type": "pdf",
+              "state": {
+                "file": "Concurrent Systems/slides/class 7.pdf"
+              },
+              "icon": "lucide-file-text",
+              "title": "class 7"
+            }
+          },
           {
             "id": "879210c00db77468",
             "type": "leaf",
@@ -230,12 +242,12 @@
   },
   "active": "43416c0d533d9ab4",
   "lastOpenFiles": [
-    "Concurrent Systems/slides/class 8.pdf",
+    "Concurrent Systems/slides/class 7.pdf",
     "Concurrent Systems/notes/7- MUTEX-free concurrency.md",
+    "Concurrent Systems/slides/class 8.pdf",
     "Concurrent Systems/notes/8 - Enhancing Liveness Properties.md",
     "Pasted image 20250325090735.png",
     "Concurrent Systems/notes/images/Pasted image 20250324091452.png",
-    "Concurrent Systems/slides/class 7.pdf",
     "Concurrent Systems/notes/6 - Atomicity.md",
     "Concurrent Systems/notes/5 - Software Transactional Memory.md",
     "Concurrent Systems/notes/4c - Dining Philosophers.md",

Concurrent Systems/notes/7- MUTEX-free concurrency.md

@@ -139,7 +139,7 @@ Idea: every operation is started by the invoking process and finalized by the ne
 This is needed for the so called ABA problem with compare&set:
 - A typical use of compare&set is
 ```
-	stmp <- X
+	tmp <- X
 	...
 	if X.compare&set(tmp, v) then ...
 ```
@@ -153,13 +153,14 @@ TOP : a register that can be read or compare&setted
 
 ```
 push(w) :=
-	while true do ⟨i,v,s⟩ <- TOP
+	while true do
-	conclude(i,v,s)
+		⟨i,v,s⟩ <- TOP
-	if i=k then
+		conclude(i,v,s)
-		return FULL
+		if i=k then
-		newtop <- ⟨i+1,w,STACK[i+1].seq_num+1⟩
+			return FULL
-		if TOP.compare&set(⟨i,v,s⟩,newtop) then
+			newtop <- ⟨i+1,w,STACK[i+1].seq_num+1⟩
-			return OK
+			if TOP.compare&set(⟨i,v,s⟩,newtop) then
+				return OK
 
 conclude(i, v, s) :=
 	tmp <- STACK[i].val