problem with mule-utf-8 ?

[Pascal Bourguignon <spam@thalassa.informatimago.com>]

Hello, 

I'm trying to make an UTF-8 file containing some katakana characters.

So, I take a new buffer, type M-x set-input-method RET japanese-katakana RET
a SPACE e SPACE i SPACE o SPACE C-x C-s, and then it says:

------------------------------------------------------------------------
These default coding systems were tried to encode text
in the buffer `test':
  utf-8 iso-latin-1
However, each of them encountered these problematic characters:
  iso-latin-1: ア エ イ オ ウ ヤ
  utf-8: ア エ イ オ ウ ヤ
The first problematic character is at point in the displayed buffer,
and C-u C-x = will give information about it.

Select one of the following safe coding systems, or edit the buffer:
  euc-jp shift_jis iso-2022-jp japanese-iso-7bit-1978-irv
  iso-2022-7bit
Or specify any other coding system
on your risk of losing the problematic characters.
------------------------------------------------------------------------

So,  what's  the  matter?  I  thought that  unicode  inclued  all  the
characters,  and  that  utf-8  was  able  to  transcribe  all  unicode
character, or not?

Of course, I insist and save  it with utf-8 encoding, then when I load
this utf-8 file later, I get rectangle frames instead of katakana...


Is this a problem with mule, or is it with unicode?


-- 
__Pascal_Bourguignon__                   http://www.informatimago.com/
----------------------------------------------------------------------
Do not adjust your mind, there is a fault in reality.