Well the stack trace of my core's is changing.

kernel and userland as of Jan 26 10:37 PST

UP kernel boots and runs fine.
MP kernel booted single-user ok, ps, date, rcorder all seem to work
(last try rcorder dumped core) so boot multi-user.

cpu0: booting secondary processors: cpu1
Mon Jan 27 :36:05 GMT 2003
swapctl: adding /dev/sd0b as swap device at priority 0
Starting file system checks:
[1]   Segmentation fault (core dumped) Jan 27 01:36:07 init: /bin/sh on /etc/rc terminated abnormally, going to single user mode
Enter pathname of shell or RETURN for /bin/sh: 
Enter terminal type []: 

We recommend creating a non-root account and using su(1) for root access.
No entry for terminal type "dumb";
using dumb terminal settings.
# halt
halt in free(): warning: malloc() has never been called.
Jan 27 01:36:40 init: kernel security level changed from 0 to 1
syncing disks... done
cpu0 halted
cpu1 halted

It was fsck this time:

Core was generated by `fsck'.
Program terminated with signal 11, Segmentation fault.

warning: current_sos: Can't read pathname for load map: Input/output error

Reading symbols from /lib/libsparc_v8.so.0...(no debugging symbols found)...
done.
Loaded symbols for /lib/libsparc_v8.so.0
Reading symbols from /lib/libc.so.12...(no debugging symbols found)...done.
Loaded symbols for /lib/libc.so.12
#0  0x101457c4 in __runetable_to_netbsd_ctype () from /lib/libc.so.12
(gdb) bt
#0  0x101457c4 in __runetable_to_netbsd_ctype () from /lib/libc.so.12
#1  0x10145ae0 in _NukeRune () from /lib/libc.so.12
#2  0x101540c0 in vfprintf_unlocked () from /lib/libc.so.12
#3  0x1014f4f4 in snprintf () from /lib/libc.so.12
#4  0x122f0 in perror ()
#5  0x123c8 in perror ()
#6  0x12584 in perror ()
#7  0x114ac in main ()
#8  0x10e8c in ___start ()
(gdb) 

--sjg