X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Ffilesys.texi;h=02808bb821c74902187a7f6b51886383860a5d71;hb=15c9fb6dabbf4425d123e5e828cc9e4f247b31a7;hp=4d663913b29e3b49dfd881d69b1de911e5027278;hpb=553ea4c4cb4a50a609ab826b361800c8a5532ec5;p=pintos-anon

diff --git a/doc/filesys.texi b/doc/filesys.texi
index 4d66391..02808bb 100644
--- a/doc/filesys.texi
+++ b/doc/filesys.texi
@@ -21,13 +21,10 @@ parts work together so that you can run VM and your filesystem at the
 same time.  Plus, keeping VM is a great way to stress-test your
 filesystem implementation.
 
-Your submission should define @code{THREAD_JOIN_IMPLEMENTED} in
-@file{constants.h} (@pxref{Conditional Compilation}).
-
 @menu
 * File System New Code::        
 * File System Synchronization::  
-* Problem 4-1 Large Files::     
+* Problem 4-1 Indexed Files::     
 * Problem 4-2 File Growth::     
 * Problem 4-3 Subdirectories::  
 * Problem 4-4 Buffer Cache::    
@@ -124,19 +121,22 @@ file system doesn't have to maintain full serialization as long as it
 follows the rules above.
 @end itemize
 
-@node Problem 4-1 Large Files
-@section Problem 4-1: Large Files
-
-Modify the file system to allow the maximum size of a file to be as
-large as the disk.  You can assume that the disk will not be larger
-than 8 MB.  In the basic file system, each file is limited to a file
-size of just under 64 kB.  Each file has a header called an index node
-or @dfn{inode} (represented by @struct{inode}) that is a table of
-direct pointers to the disk blocks for that file.  Since the inode is
-stored in one disk sector, the maximum size of a file is limited by
-the number of pointers that will fit in one disk sector.  Increasing
-the limit to 8 MB will require you to implement doubly-indirect
-blocks.
+@node Problem 4-1 Indexed Files
+@section Problem 4-1: Indexed Files
+
+The basic file system allocates files as a single extent, making it
+vulnerable to external fragmentation.  Eliminate this problem by
+modifying the inode structure.  In practice, this probably means using
+an index structure with direct, indirect, and doubly indirect blocks.
+(You are welcome to choose a different scheme as long as you explain the
+rationale for it in your design documentation, and as long as it does
+not suffer from external fragmentation.)
+
+You can assume that the disk will not be larger than 8 MB.  You must
+support files as large as the disk (minus metadata).  Each inode is
+stored in one disk sector, limiting the number of block pointers that it
+can contain.  Supporting 8 MB files will require you to implement
+doubly-indirect blocks.
 
 @node Problem 4-2 File Growth
 @section Problem 4-2: File Growth