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index 92f95ff..fe2f714 100644
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@@ -45,19 +45,19 @@
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diff --git a/Concurrent Systems/notes/7- MUTEX-free concurrency.md b/Concurrent Systems/notes/7- MUTEX-free concurrency.md
index e69de29..9f5d79e 100644
--- a/Concurrent Systems/notes/7- MUTEX-free concurrency.md	
+++ b/Concurrent Systems/notes/7- MUTEX-free concurrency.md	
@@ -0,0 +1,10 @@
+Critical sections (locks) have drawbacks:
+- if not put at the right level of granularity, they unnecessarily reduce concurrency
+- delays of one process may affect the whole system
+
+**MUTEX-freedom:** the only atomicity is the one provided by the primitives themselves (no wrapping of code into CSs)
+	the liveness properties used so far cannot be used anymore, since they rely on CSs.
+(example: if we have only atomic R/W registers, these are the only atomic things that we have. But we may also have atomic primitives like *test&set*, *compare&swap* ecc.).
+
+1. **Obstruction freedom:**
+
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