X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=doc%2Fuserprog.texi;h=75123849b0622bcd7aa312a462cba104a36761de;hb=3bccbf4661eb75a871b8c3a2d91fcb033ad6f587;hp=d401fda025f1f98b81ed78a31c743ccbd30bf68e;hpb=71a7177a212dbecb048aaa8db4ff54620ff25464;p=pintos-anon

diff --git a/doc/userprog.texi b/doc/userprog.texi
index d401fda..7512384 100644
--- a/doc/userprog.texi
+++ b/doc/userprog.texi
@@ -19,6 +19,12 @@ start with a fresh copy.  No code from project 1 is required for this
 assignment.  The ``alarm clock'' functionality may be useful in
 projects 3 and 4, but it is not strictly required.
 
+You might find it useful to go back and reread how to run the tests
+(@pxref{Testing}).  In particular, the tests for project 2 and later
+projects will probably run faster if you use the qemu emulator, e.g.@:
+via @code{make check PINTOSOPTS='--qemu'}.  The qemu emulator is
+available only on the Linux machines.
+
 @menu
 * Project 2 Background::        
 * Project 2 Suggested Order of Implementation::  
@@ -222,9 +228,10 @@ pintos -p ../../examples/echo -a echo -- -f -q run 'echo x'
 
 If you don't want to keep the file system disk around for later use or
 inspection, you can even combine all four steps into a single command.
-The @code{--fs-disk=2} option creates a temporary disk just for the
-duration of the @command{pintos} run.  The Pintos automatic test suite
-makes extensive use of this syntax:
+The @code{--fs-disk=@var{n}} option creates a temporary disk
+approximately @var{n} megabytes in size just for the duration of the
+@command{pintos} run.  The Pintos automatic test suite makes extensive
+use of this syntax:
 
 @example
 pintos --fs-disk=2 -p ../../examples/echo -a echo -- -f -q run 'echo x'
@@ -251,7 +258,8 @@ programs.  The @file{Makefile} in this directory
 compiles the provided examples, and you can edit it
 compile your own programs as well.
 
-Pintos loads @dfn{ELF} executables.  ELF is a file format used by Linux,
+Pintos can load @dfn{ELF} executables with the loader provided for you
+in @file{userprog/process.c}.  ELF is a file format used by Linux,
 Solaris, and many other operating systems for object files,
 shared libraries, and executables.  You can actually use any compiler
 and linker that output 80@var{x}86 ELF executables to produce programs
@@ -683,7 +691,8 @@ actual number written, or -1 if no bytes could be written at all.
 
 Fd 1 writes to the console.  Your code to write to the console should
 write all of @var{buffer} in one call to @func{putbuf}, at least as
-long as @var{size} is not bigger than a few hundred bytes.  Otherwise,
+long as @var{size} is not bigger than a few hundred bytes.  (It is
+reasonable to break up larger buffers.)  Otherwise,
 lines of text output by different processes may end up interleaved on
 the console, confusing both human readers and our grading scripts.
 
@@ -777,7 +786,8 @@ hurt even now.
 You can use @func{file_deny_write} to prevent writes to an open file.
 Calling @func{file_allow_write} on the file will re-enable them (unless
 the file is denied writes by another opener).  Closing a file will also
-re-enable writes.
+re-enable writes.  Thus, to deny writes to process's executable, you
+must keep it open as long as the process is still running.
 
 @node Project 2 FAQ
 @section FAQ
@@ -789,6 +799,12 @@ Here's a summary of our reference solution, produced by the
 @command{diffstat} program.  The final row gives total lines inserted
 and deleted; a changed line counts as both an insertion and a deletion.
 
+The reference solution represents just one possible solution.  Many
+other solutions are also possible and many of those differ greatly from
+the reference solution.  Some excellent solutions may not modify all the
+files modified by the reference solution, and some may modify files not
+modified by the reference solution.
+
 @verbatim
  threads/thread.c     |   13 
  threads/thread.h     |   26 +