vault backup: 2025-03-17 09:39:23

.obsidian/workspace.json

@@ -216,10 +216,10 @@
       "companion:Toggle completion": false
     }
   },
-  "active": "071b6cd23e4b1e9d",
+  "active": "6edd4157a160e462",
   "lastOpenFiles": [
-    "Concurrent Systems/notes/4b -.md",
     "Concurrent Systems/slides/class 4.pdf",
+    "Concurrent Systems/notes/4b -.md",
     "Concurrent Systems/slides/class 5.pdf",
     "HCIW/slides/4 HUI2016-6-forcefeedback.pdf",
     "HCIW/slides/3b Haptic slides.pdf",

Concurrent Systems/notes/4b -.md

@@ -35,5 +35,24 @@ Of course, `signal()` will have no effect on the last process who calls it.
 - For every condition C, a semaphore SEMC init at 0 and an integer $N_{C}$ init at 0 (to store and count the number of suspended processes on the given condition)
 - A semaphore PRIO init at 0 and an integer $N_{PR}$ init at 0 (to store and count the number of processes that have performed a signal, and so have priority to re-enter the monitor)
 
-1. Every monitor operation starts with `MUTEX.down()` and ends with `if NPR > 0 then PRIO.up() else MUTEX.up()`
+Every monitor operation starts with `MUTEX.down()` and ends with `if NPR > 0 then PRIO.up() else MUTEX.up()`
-2. 
+
+```
+C.wait() :=
+	NC++
+	if NPR > 0 then
+		PRIO.up()
+	else
+		MUTEX.up()
+	SEMC.down()
+	NC--
+	return
+
+C.signal() :=
+	if NC > 0 then
+		NPR++
+		SEMC.up()
+		PRIO.down()
+		NPR--
+```
+