Update

[pintos-anon] / TODO

diff --git a/TODO b/TODO
index 31606d182661ee33ae3ceefb616355d5f7daac19..da3937dec3f973f08b71e378cecd332bf9ae4266 100644 (file)
--- a/TODO
+++ b/TODO
@@ -1,18 +1,31 @@
 -*- text -*-
 
-* Miscellaneous:
+* Remove names from synchronization primitives?  They don't seem
+  useful in practice.
 
-  - Currently the `pintos' utility has a broken return code policy: it
-    returns 1 to indicate success.  It inherited this mistake from
-    Bochs, which does something similar.  This needs to be fixed.
+* debug_backtrace() in kernel should only dereference valid pointers.
 
-* Userprog project:
+* Mention how to use add-symbol-file in gdb.
+
+* We need better and more example programs.
+
+  - Need an mmap example program as a replacement for the crappy mmap FAQ
+    question.
 
-  - Move `join' implementation here, from `threads' project, to help
-    normalize the project difficulties.
+  - How about `diff' and `cmp' programs?
 
-  - The semantics of the join system call should change so that it
-    only returns the exit code once.
+* Threads:
+
+  - mlfqs tests suck.  They aren't even correct, e.g. the amarv
+    submission from win0405 is graded incorrectly.
+
+* Userprog project:
+
+  - Don't emphasize that stuff needs to be copied from user space to
+    kernel space.  Instead, emphasize validation and suggest that
+    copying is a common solution and that it will be necessary in
+    project 3 and in real OSes.  Also revise the grading criteria to
+    match.
 
   - Mark read-only pages as actually read-only in the page table.  Or,
     since this was consistently rated as the easiest project by the
@@ -24,6 +37,35 @@
     Alternately we could just remove the synchronization on pid
     selection and check that students fix it.
 
+* VM project:
+
+  - Discuss the perils of mixing dirty bits between kernel and user virtual
+    memory.
+
+  - Sample solution.
+
+  - Update grading/vm to reflect new mmap, munmap forms.
+
+* Filesys project:
+
+  - Increase maximum disk size from 8 MB to something that actually
+    requires doubly indirect nodes.  There is a negative pressure here
+    from the bitmap object--perhaps we need a specialized bitmap that
+    doesn't have to be all in-memory at once.
+
+    Alternatively, shrink the inode size.
+
+  - Add option to disable buffer cache.
+
+  - Sample solution.
+
+  - Need a better way to measure performance improvement of buffer
+    cache.  Some students reported that their system was slower with
+    cache--likely, Bochs doesn't simulate a disk with a realistic
+    speed.
+
+  - Clarify effect of remove(cwd).
+
 * Documentation:
 
   - Finish writing tour.
@@ -34,19 +76,21 @@
   - Add explanations of what "real" OSes do to give students some
     perspective.
 
+  - GNU make 3.80 or later is required.
+
 * Assignments:
 
   - Add extra credit:
 
     . Low-level x86 stuff, like paged page tables.
 
+    . Specifics on how to implement sbrk, malloc.
+
     . Other good ideas.
 
-  - mmap/munmap should use segment IDs like Nachos.  Too hard
-    otherwise.
+    . opendir/readdir/closedir
 
-  - Add src/testcases/vm, src/testcases/filesys and make it clear to use
-    them?
+    . everything needed for getcwd()
 
 * Tests:
 
@@ -60,3 +104,9 @@
     too long (especially when SHOW_PROGRESS is turned on) and doesn't
     show significant improvement.
 
+* Code:
+
+  - Need an optimization barrier and an explanation of it in the
+    documentation.
+
+  - Need to check the wait system call more thoroughly.