vault backup: 2025-03-17 10:34:23

.obsidian/workspace.json

@@ -34,9 +34,9 @@
               "type": "pdf",
               "state": {
                 "file": "Concurrent Systems/slides/class 5.pdf",
-                "page": 2,
+                "page": 4,
                 "left": -27,
-                "top": 266,
+                "top": 379,
                 "zoom": 0.5754156769596199
               },
               "icon": "lucide-file-text",

Concurrent Systems/notes/5 - Software Transactional Memory.md

@@ -23,4 +23,12 @@ The key issue is ensuring consistency of the shared memory
 
 Implementation: every transaction uses a local working space
 - For every shared register: the first READ copies the value of the reg. in the local copy; successive READs will then read from the local copy
-- Every WRITE modifies the local copy and puts the final
+- Every WRITE modifies the local copy and puts the final value in the shared memory only at the end of the transaction (if it has not been aborted)
+
+4 operations:
+- `begin_T()`: initializes the local control variables
+- `X.read_T(), X.write_T()`: described above
+- `try_to_commit_T()`: decides whether a transaction (non-aborted) can commit
+
+#### A Logical Clock based STM system
+All the READs perform if no inconsistencies arise, or before any inconsistency