MB  mount      cyl   size     start
 40  /          110   79200         0
120  swap       325  253440     79200 
170  /usr       460  331200    313200
  5  /e          15   10800    644400
 89  /var       241  173520    655200
---            ----
424	       1151

boot-device           disk                           disk
だけでは不充分で、
diag-device           disk                           net
が必要と、以前から思っていたが、最近確信するに至った。

The fstab is configured as follows:

/dev/sd0a / ffs rw 1 1
/dev/sd0d /usr ffs rw 1 2
/dev/sd0e /e ffs rw 1 2
/dev/sd0h /var ffs rw 1 2
/dev/sd0b none swap sw 0 0

You may wish to edit the fstab.  For example, you may need to resolve
dependencies in the order which the filesystems are mounted.  You may
also wish to take this opportunity to place NFS mounts in the fstab.
This would be especially useful if you plan to keep '/usr' on an NFS
server.

Edit the fstab? [n] 

exec: mount_ffs -o async /dev/sd1a /mnt
mount_ffs: /dev/sd1a on /mnt: Device not configured

FATAL ERROR:  Cannot mount filesystems.
Double-check your configuration
and restart the installation process.
# 

/dev/sd0c       /mount_union    ffs     rw 1 3
/mount_union    /usr            union   rw 0 0
/e              /etc    union   rw 0 0
で、いまの様子は
ci# df 
Filesystem           1K-blocks     Used    Avail Capacity  Mounted on
/dev/sd1a                38239    19757    16570    54%    /
/dev/sd1d               160015   148387     3627    97%    /usr
/dev/sd1h                83623      619    78822     0%    /var
/dev/sd1e                 5199        1     4938     0%    /e
/dev/sd0c               400518       13   380479     0%    /mount_union
<above>:/mount_union    548905   148400   380479    28%    /usr
<above>:/e               24956    19758     4938    80%    /etc
ci#