X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=TODO;h=d4afd5c0ad8b2782c3403364270b50bdc385c903;hb=12399ec5a71cb2fde72835f6abde1cef8e6057e6;hp=f02d750548fb15914974bcd99d7515bcb8efb49c;hpb=c37b82251bbe85edf2d46284f6d4b43b92b09182;p=pintos-anon

diff --git a/TODO b/TODO
index f02d750..d4afd5c 100644
--- a/TODO
+++ b/TODO
@@ -1,20 +1,80 @@
 -*- text -*-
 
-* Code:
+* The tests in tests/ don't apply the grading patches.
+
+* We need better and more example programs.
+
+  - Need an mmap example program as a replacement for the crappy mmap FAQ
+    question.
+
+  - How about `diff' and `cmp' programs?
+
+* Make it clear that the students own their code, because there was some
+  confusion on that point.
+
+* Threads:
+
+  - join-invalid doesn't compile if tid_t is not scalar type.
+
+  - 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.
+
+  - Move `join' implementation here, from `threads' project, to help
+    normalize the project difficulties.
+
+  - The semantics of the join system call should change so that it
+    only returns the exit code once.
+
+  - Mark read-only pages as actually read-only in the page table.  Or,
+    since this was consistently rated as the easiest project by the
+    students, require them to do it.
+
+  - Don't provide per-process pagedir implementation but only
+    single-process implementation and require students to implement
+    the separation?  This project was rated as the easiest after all.
+    Alternately we could just remove the synchronization on pid
+    selection and check that students fix it.
+
+* VM project:
 
-  - Speed up disk routines: filling an 8 MB disk takes a long time.
-    (They're only slow because timer_sleep always waits for at least
-    one timer tick.)
+  - Discuss the perils of mixing dirty bits between kernel and user virtual
+    memory.
 
-  - userprog project should mark read-only pages as actually read-only
-    in the page table.  Or, since this was consistently rated as the
-    easiest project by the students, require them to do it.
+  - Sample solution.
 
-  - For userprog project, don't provide per-process pagedir
-    implementation but only single-process implementation and require
-    students to implement the separation?  This project was rated as
-    the easiest after all.  Alternately we could just remove the
-    synchronization on pid selection and check that students fix it.
+  - 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 mkdir and ls example user programs.
+
+  - Add option to disable buffer cache.
+
+  - Get rid of "dump" commands--they're not really useful.
+
+  - 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:
 
@@ -23,19 +83,22 @@
   - Add "Digging Deeper" sections that describe the nitty-gritty x86
     details for the benefit of those interested.
 
+  - Add explanations of what "real" OSes do to give students some
+    perspective.
+
 * Assignments:
 
   - Add extra credit:
 
     . Low-level x86 stuff, like paged page tables.
 
+    . Specifics on how to implement sbrk, malloc.
+
     . Other good ideas.
 
-  - The semantics of the join system call should change so that it
-    only returns the exit code once.
+    . opendir/readdir/closedir
 
-  - mmap/munmap should use segment IDs like Nachos.  Too hard
-    otherwise.
+    . everything needed for getcwd()
 
   - Add src/testcases/vm, src/testcases/filesys and make it clear to use
     them?
@@ -52,3 +115,11 @@
     too long (especially when SHOW_PROGRESS is turned on) and doesn't
     show significant improvement.
 
+* Code:
+
+  - Rewrite quick_sort() to use heap sort, for O(1) stack usage.
+
+  - Rewrite list_sort() to use merge sort, for O(1) heap usage.
+
+  - Make list_elem and hash_elem a struct, by encapsulating a struct
+    list_elem inside a struct hash_elem as a member.