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

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