Rewrite the I/O port code.

[pintos-anon] / ta-advice / HW4

diff --git a/ta-advice/HW4 b/ta-advice/HW4
index f9a6d22384a39d716d689204d00510ed622e7ac1..225c08b223241f3fa3f15f96f679821ccfa67d1a 100644 (file)
--- a/ta-advice/HW4
+++ b/ta-advice/HW4
@@ -147,7 +147,8 @@ A3:
 
            This is not the same as taking a lock across a couple of
            lines of code to check or set a variable in a race-free
-           way, etc.  That's fine.
+           way, etc.  That's fine.  The issue is waiting for I/O to
+           complete, not for updating little bits of metadata.
 
 A4:
 
@@ -178,7 +179,8 @@ A5:
 
     Many answers are implicitly predicated on the fact that Pintos
     locks and semaphores have fair, first-come, first-served queuing.
-    Most students don't mention it, though.
+    Most students don't mention it, though.  Give a bonus point if
+    they do.
 
     The typical answer depends on the answer to A4:
 
@@ -253,6 +255,8 @@ A6:
 
         - High overhead for small files.
 
+    At least two reasons must be mentioned.
+
                             SUBDIRECTORIES
                             ==============
 
@@ -436,6 +440,8 @@ B6:
           working directory: I haven't seen any of these groups make
           sensible claims yet.
 
+    At least two reasons must be given.
+
                              BUFFER CACHE
                              ============
 
@@ -491,8 +497,7 @@ C2:
 
     Many schemes are possible.  For full credit, students must use an
     algorithm that is at least as good as the second-chance (clock)
-    algorithm, and they must take the difference between data and
-    metadata into account in some way.
+    algorithm.
 
     Some implementations I've seen, with comments: