Tux3 now has a command interpreter to aid in debugging, with commands

like:
   tux3 make foodev
that makes a filesystem on device foodev, which can also be a file.  It

normally is a file for me and I make it sparse like this:
   dd if=/dev/zero of=foodev bs=1 count=1 seek=100K
I can see how many blocks tux3 actually used in it by:
   du foodev
less the few blocks that the sparse file has for metatdata and the

little blob of data at the end that dd puts there.  (I don't know how

to make dd truncate without writing, I am not sure it is possible.)
Then:
   echo "hello world!" | tux3 write foodev foo
creates and writes to file foo in foodev.  A subsequent write will

fail with EEXIST, which is maybe not quite what we want.
Finally:
  tux3 read foodev foo
outputs "hello world!".
The following command sequence is particularly interesting:
   tux3 make --blocksize 256 foodev

   echo hello | tux3 write --seek 72057594037927930 foodev foo

   tux3 read --seek 72057594037927930 foodev foo
It writes "hello" into the last few bytes of a 64 Petabyte file, the

largest that Tux3 can create with 256 byte blocks :-)
Using "du foodev" before and after creating and writing to its

filesystem shows that Tux3 only used 8K for the entire filesystem

including the multi-petabyte sparse file, root directory, inode table

and allocation bitmaps.
To build tux3:
   g99 -g -Wall -lpopt buffer.c diskio.c tux3.c -otux3
Regards,
Daniel
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