concurrency.md

@@ -25,19 +25,6 @@ Papers and other docs:
 - [ A Draft report addendum](http://www.haskell.org/ghc/docs/papers/threads.ps.gz) (a shorter version of the above paper).
 - [ Software Transactional Memory](http://research.microsoft.com/~simonpj/papers/stm/)
 
-## Pros
-
-
-- Vital for some modern applications and large applications commonly require it.
-- Stable `MVar` implementation is well understood and tested.
-
-## Cons
-
-
-- Imposes non trivial implementation constraints.
-- Providing a 'select' and non-blocking IO would be enough to allow people to implement something like it themselves in haskell and are provided by most systems as primitives.
-- Things like the 'poor man's concurrency monad' can achieve some of the benefits
-
 ---
 
 
@@ -51,8 +38,10 @@ Papers and other docs:
 At least the following interface will be provided
 
 
-- Control.Concurrent.MVar - everything except addMVarFinalizer
-- Control.Concurrent - ThreadId?,myThreadId,forkIO,yield,threadWaitRead\[1\],threadWaitWrite\[1\],threadDelay
+- [ Control.Concurrent.MVar](http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Concurrent-MVar.html) - everything except `addMVarFinalizer`
+- [ Control.Concurrent](http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Concurrent.html) - `ThreadId`, `myThreadId`, `forkIO`, `yield`, `sleep` (replaces `threadDelay`).
+- `Control.Concurrent.Chan`, `Control.Concurrent.QSem`, `Control.Concurrent.QSemN`,
+  `Control.Concurrent.SampleVar`
 
 
 the FFI must be able to handle 'concurrent nonrentrant' imports, but not
@@ -101,21 +90,24 @@ perhaps a better phrasing of the first proposal exists, in practice, from a user
 
 
 
-yield is guarenteed to choose an alternate thread if another one exists and is
+`yield` is guarenteed to choose an alternate thread if another one exists and is
 runnable.
 
 
 
-threadDelay guarentees the thread will wait as long as its argument at a
+`sleep` guarentees the thread will wait as long as its argument at a
 minimum. it may be blocked for longer.
 
 
-## notes
+## I/O
+
+
+
+I/O operations from `System.IO`, `System.Directory`, `System.Process` (and others?) do not prevent other threads from making progress when they are waiting for I/O to complete.
 
 
 
-\[1\] may be moved to another module (Control.Concurrent.IO?) , routines working on Handles should be
-added too.
+We could provide a lower-level non-blocking I/O interface along the lines of `threadWaitRead`, `threadWaitWrite`, perhaps in `Control.Concurent.IO`.
 
 
 # Optional extensions to basic standard