I'm still playing with my PB520 from time to time. As I understand from
Allen's messages that the current kernels are actually built from the
current kernel sources, I have given my PB520 a try again.

The log from the serial console is included below. Basically it stops
while trying to figure the swap configuration. It seems that a SCSI
request is being queued, but never really executed.

By the way, if the kernel is compiled with options DIAGNOSTICS, it'll
panic with "no pcb". This sounds like one of the problems that Allen
has been investigating lately ... If it'll help, I can add DIAGNOSTICS
again and send a trace-back or whatever at this panic.

The printf outputs added by me indicates that the kernel hangs while
executing

	nblks = (*bdevsw[maj].d_psize)(swp->sw_dev);

The stack trace was produced by entering CMD-PowerOn on the PB's key-
board to get into the debugger and then entering the trace command via
the serial console.

Sources should be current (using sup) as of today.

But anyway -- can anyone tell why the kernel hangs with outstanding
SCSI disk i/o at this point of time? One of the things that I don't
understand is why it hangs here -- it is not the first disk access.

regards
Erik Bertelsen

NetBSD 1.2B (KRAFT) #26: Mon Nov 11 20:53:22 MET 1996
    erik@cx.ebe.dk:/home/src/sys/arch/mac68k/compile/KRAFT
Apple Macintosh PowerBook 500  (68040)
real mem = 37748736
avail mem = 34185216
using 204 buffers containing 835584 bytes of memory
ebe: configure: (entry).
ebe: configure: VIA initialised.
mrg: kernel has no ROM vectors for this machine!
ebe: configure: mrg initialised.
ebe: configure: rtclock started.
adb: using serial console
ebe: configure: adb initialised.
mainbus0 (root)
obio0 at mainbus0
adb0 at obio0 (ADB event device)
asc0 at obio0 Apple sound chip.
ncrscsi0 at obio0
scsibus0 at ncrscsi0
sd0 at scsibus0 targ 0 lun 0: <IBM, DHAS-2540, S640> SCSI1 0/direct fixed
sd0: 515MB, 2770 cyl, 4 head, 95 sec, 512 bytes/sec
zsc0 at obio0 chip type 0 
zstty0 at zsc0 channel 0 (console)
zstty1 at zsc0 channel 1
fpu0 at obio0 (emulator)
ebe: configure: mainbus configured.
ebe: configure: boot dev configured.
root on sd0a swap on sd0b
ebe: configure: root dev configured.
ebe: enter swapconf.
ebe: check maj: 4 (nblkdev: 20).
ebe: now calculate nblks.
Panic switch: PC is 0x3222.
Stopped at      _Debugger+0x6:  unlk    a6
db> where
No such command
db> w
Nothing written.
db> trace
_Debugger(65abe,3222,c9e28,32be,2704) + 6
_nmihand(2704,1,11,2204,0) + 22
_lev7intr(?)
_tsleep(6bfff00,11,53204,0) + 12
_scsi_execute_xs(6bfff00) + 64
_scsi_scsi_cmd(6c00fe0,c9eae,6,0,0) + 90
_scsi_prevent(6c00fe0,1,180) + 46
_sdopen(401,0,6000,0) + ac
_sdsize(401,633d3,124,1cdd8,4407c) + 16
_swapconf(63297,63271,6324c,1cdd8,c9f7c) + 74
_configure(64b2e,cc,cc000,64b1d,209a000) + 82
_cpu_startup(7276c,14147,14020,80010322,ffffcffc) + 448
_main() + 4a
_main() + 4a