X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Ffilesys.texi;h=1b666b3b6e3ca24dbc3c1579ee3c8df4b10b934f;hb=ccbd8543c5ad589e878a3924b2dd39d5a6a2f39d;hp=9075c9a5a3c2f113319b980fb205bba596d00b2a;hpb=a96d2712f349629d7fe2186e2620f1704cbdee50;p=pintos-anon

diff --git a/doc/filesys.texi b/doc/filesys.texi
index 9075c9a..1b666b3 100644
--- a/doc/filesys.texi
+++ b/doc/filesys.texi
@@ -287,11 +287,12 @@ disk.  Otherwise, fetch the block from disk into cache, evicting an
 older entry if necessary.  You are limited to a cache no greater than 64
 sectors in size.
 
-Be sure to choose an intelligent cache replacement algorithm.
-Experiment to see what combination of accessed, dirty, and other
-information results in the best performance, as measured by the number
-of disk accesses.  For example, metadata is generally more valuable to
-cache than data.
+You must implement a cache replacement algorithm that is at least as
+good as the ``clock'' algorithm.  Your algorithm must also account for
+the generally greater value of metadata compared to data.  Experiment
+to see what combination of accessed, dirty, and other information
+results in the best performance, as measured by the number of disk
+accesses.
 
 You can keep a cached copy of the free map permanently in memory if you
 like.  It doesn't have to count against the cache size.