Clean up comments.

build/proto

@@ -1,9 +1,9 @@
 # Prototype file for PDP-7 Unix filesystem layout
 #
 # Entries are one of:
-#    filename f[r-][w-][r-][r-] uid local_file_to_insert
-#    dirname  d[r-][w-][r-][r-] uid [inumber]
-#    device   i[r-][w-][r-][r-] uid inumber
+#    filename f[r-][w-][r-][w-] uid local_file_to_insert
+#    dirname  d[r-][w-][r-][w-] uid [inumber]
+#    device   i[r-][w-][r-][w-] uid inumber
 #    link     l---- inumber
 #
 # The top directory's name is ignored

tools/mkfs7

@@ -84,7 +84,7 @@ sub init_freelist {
 # Set up a block with nine free block numbers in it,
 # plus a pointer to the next block in the free list.
 # Return the block number of this block with nine free block numbers
-# or 0 if we did not set up out a block.
+# or 0 if we did not set up a block.
 # The argument is only used to make the debug output pleasing
 sub write_freelist {
    no warnings 'recursion';