From: John Hodge <tpg@mutabah.net>
Date: Sun, 27 Feb 2011 11:13:27 +0000 (+0800)
Subject: Notes on how to implement select()
X-Git-Tag: rel0.10~191
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=58d2f56cd5211d93b4984e1f66a8aba5f0599942;p=tpg%2Facess2.git

Notes on how to implement select()
---

diff --git a/Design Notes/VFS - Select.txt b/Design Notes/VFS - Select.txt
new file mode 100644
index 00000000..cceef5ce
--- /dev/null
+++ b/Design Notes/VFS - Select.txt	
@@ -0,0 +1,12 @@
+select()
+- Implemented using a wait queue for every file descriptor
+- That requires waiting on sockets to be centeralised
+
+All wait tasks (reads on VTerm, Pipes, PTYs, network sockets) use the kernel
+version of select with an inifinite timeout.
+They then signal the VFS using their VFS node pointer as a reference
+
+The VFS function select()
+- Maintains a list of processes on each node (if select has been called on that node)
+- Each process maybe has a semaphore on it (to use the semaphore code to maintain the process list)
+ > Could maybe use a mutex instead