Thanks to the help from Skeelo and Bob Nestor, this problem
was solved.  Here are the summary and another one.

SUNAGAWA Keiki <kei@ps.yokogawa.co.jp>  wrote:

Keiki> I purchased IBM DCAS-34330 (narrow) and tried to use
Keiki> it under NetBSD, but no success.  Is anybody else
Keiki> there experienced similer problem?

* More than 3 usr partitions trigered the problem.

Here's a part of disklabel of the drive I'm currently using
DORS-32160.  Disklabel says it has 8 partitions, so I
wrongly thought 8 partitions are ok.  Unknown (scratch)
partitions seems to be ignored.

8 partitions:
#        size   offset    fstype   [fsize bsize   cpg]
  a:    40960      192      4.2BSD        0     0     0   # (Cyl.    0*- 66*)
  b:   163840    41152        swap                        # (Cyl.   66*- 333*)
  c:  4127761        0      unused        0     0         # (Cyl.    0 - 6711*)
  d:       96       96     unknown                        # (Cyl.    0*- 0*)
  e:   819200   204992         HFS                        # (Cyl.  333*- 1665*)
  f:   131068  1269952      4.2BSD        0     0     0   # (Cyl. 2064*- 2278*)
  g:   245760  1024192      4.2BSD        0     0     0   # (Cyl. 1665*- 2064*)
  h:  2726741  1401020      4.2BSD        0     0     0   # (Cyl. 2278*- 6711*)

Here's that of DCAS-34330.  Now it's ok.

7 partitions:
#        size   offset    fstype   [fsize bsize   cpg]
  a:    40960       96      4.2BSD        0     0     0   # (Cyl.    0*- 40*)
  b:   196608    41056        swap                        # (Cyl.   40*- 231*)
  c:  8467200        0      unused        0     0         # (Cyl.    0 - 8252*)
  d:  1024000   237664         HFS                        # (Cyl.  231*- 1229*)
  e:   262144  2490464      4.2BSD        0     0     0   # (Cyl. 2427*- 2682*)
  f:  5714592  2752608      4.2BSD        0     0     0   # (Cyl. 2682*- 8252*)
  g:  1228800  1261664      4.2BSD        0     0     0   # (Cyl. 1229*- 2427*)

Previously, I splitted f partition into two parts and had 4
usr partitions, and that was the problem.  I didn't tested
changing partition type of d from HfS into usr partition,
though.

Keiki> I'm going to try (a) kernels with ncr driver, (b)
Keiki> upgrading my binaries to 1.3.2.

I didn't do this since my problem is solved before try.



* While handling the problem I noticed that while I'm
connecting my machine to ISP w/ modem, invoking disklabel
caused panic.  It is reproducable even if accessing good
disklabels mentiond above.  While PPP connection is closing,
there's no problem with invoking disklabel.

Any thoughts would be appreciated.

--
SUNAGAWA Keiki <kei@ps.yokogawa.co.jp>
Happy Hacking!