X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=doc%2Fvm.texi;h=37b53f766d9f710b8b9ed134846ae7b2abbc6843;hb=802376f1c03544a1f0576775d178f288f58b2315;hp=6176bbd8dbf4ad38a170347586b18866b8aaa779;hpb=f7bc12fb5e4c3eb3ebb633f99b8b266622fc57f7;p=pintos-anon

diff --git a/doc/vm.texi b/doc/vm.texi
index 6176bbd..37b53f7 100644
--- a/doc/vm.texi
+++ b/doc/vm.texi
@@ -316,12 +316,12 @@ Some way of translating in software from virtual page frames to
 physical page frames.  Pintos provides a hash table that you may find
 useful for this purpose (@pxref{Hash Table}).
 
-It is possible to do this translation without adding a new data
-structure, by modifying the code in @file{userprog/pagedir.c}.  However,
-if you do that you'll need to carefully study and understand section
-3.7, ``Page Translation Using 32-Bit Physical Addressing,'' in
-@bibref{IA32-v3a}, and in practice it is probably easier to add a new
-data structure.
+You don't strictly need a new data structure for this.  You could
+instead modify the code in @file{userprog/pagedir.c}.  If you do that
+you'll need to thoroughly understand how 80@var{x}86 page tables work
+by, e.g.,@: studying section 3.7, ``Page Translation Using 32-Bit
+Physical Addressing,'' in @bibref{IA32-v3a}.  In practice, most groups
+use a separate data structure.
 
 @item
 Some way of finding a page on disk (in a file or in swap) if it is not
@@ -420,11 +420,10 @@ Bits}) to implement an approximation to LRU.  Your algorithm should
 perform at least as well as the ``second chance'' or ``clock''
 algorithm.
 
-Your design should allow for parallelism.  Multiple processes should
-be able to process page faults at once.  If one page fault require
+Your design should allow for parallelism.  If one page fault requires
 I/O, in the meantime processes that do not fault should continue
-executing and other page faults that do not require I/O should be able to
-complete.  These criteria require some synchronization effort.
+executing and other page faults that do not require I/O should be able
+to complete.  These criteria require some synchronization effort.
 
 @node Lazy Loading
 @subsection Lazy Loading
@@ -713,7 +712,7 @@ with the file mapped into your address space, you can directly address
 it like so:
 
 @example
-write (addr, 64, STDOUT_FILENO);
+write (STDOUT_FILENO, addr, 64);
 @end example
 
 Similarly, if you wanted to replace the first byte of the file,