I have been trying to use an old DECpc XL560 Pentium-60 box as an X-window
terminal, but I have encountered the following bizarre behavior.  I don't
believe I saw this prior to attaching a SCSI drive to the built-in NCR
810 SCSI controller.

If I do anything that does much I/O with my SCSI drive on the built-in
NCR, my system clock becomes seriously handicapped.  The apparent tick-
rate seems to shift several orders of magnitude into the slow category. 
For all intents and purposes, the clock has about stopped.

I left the system running doing nothing over the long weekend, after a
fresh reboot.  When I did an ntpdate this morning the clock was off by
-81 seconds and change.  That is without xntpd running of course.

I then did a sup of -current which I'd not done since July 2nd and the
result of course involved plenty of changes (I'm archiving on the SCSI).

Now my clock is nearly comatose.  This behavior remains until I reboot.

Has anyone seen this sort of behavior?  Can I fix it?

Thanks!

-- Ken Wellsch

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NetBSD 1.4D (XL560) #0: Fri Jul  2 12:09:23 EDT 1999
    kwellsch@xl560:/fsys/src/sys/arch/i386/compile/XL560
cpu0: family 5 model 1 step 5
cpu0: Intel Pentium (586-class)
total memory = 48764 KB
avail memory = 43576 KB
using 635 buffers containing 2540 KB of memory
mainbus0 (root)
pci0 at mainbus0 bus 0: configuration mode 2
pci0: i/o enabled, memory enabled
pchb0 at pci0 dev 0 function 0
pchb0: Intel 82434LX/NX PCI, Cache and Memory Controller (PCMC) (rev. 0x03)
ncr0 at pci0 dev 1 function 0: ncr 53c810 fast10 scsi
ncr0: interrupting at irq 15
ncr0: minsync=25, maxsync=206, maxoffs=8, 16 dwords burst, normal dma fifo
ncr0: single-ended, open drain IRQ driver
ncr0: restart (scsi reset).
scsibus0 at ncr0: 8 targets, 8 luns per target
sd0 at scsibus0 targ 0 lun 0: <SEAGATE, ST41600N SUN1.3G, 0040> SCSI2 0/direct f
ixed
sd0(ncr0:0:0): 5.0 MB/s (200 ns, offset 8)
sd0: 1307 MB, 2099 cyl, 17 head, 75 sec, 512 bytes/sect x 2676846 sectors
pcib0 at pci0 dev 2 function 0
pcib0: Intel 82378ZB System I/O (SIO) (rev. 0x03)
vga1 at pci0 dev 6 function 0: Weitek P9000 (rev. 0x03)
wsdisplay0 at vga1: console (80x25, vt100 emulation)
wsdisplay0: screen 1 added (80x25, vt100 emulation)
wsdisplay0: screen 2 added (80x25, vt100 emulation)
wsdisplay0: screen 3 added (80x25, vt100 emulation)
wsdisplay0: screen 4 added (80x25, vt100 emulation)
wsdisplay0: screen 5 added (80x25, vt100 emulation)
de0 at pci0 dev 7 function 0
de0: interrupting at irq 9
de0: SMC 9332DST 21140 [10-100Mb/s] pass 1.2
de0: address 00:00:c0:aa:3d:e7
de0: enabling 10baseT port
isa0 at pcib0
aha0 at isa0 port 0x330-0x333 irq 11 drq 5
aha0: model AHA-1542CF, firmware C.0
aha0: unlocking mailbox interface
aha0: async, parity
scsibus1 at aha0: 8 targets, 8 luns per target
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
wdc0 at isa0 port 0x1f0-0x1f7 irq 14
wd0 at wdc0 channel 0 drive 0: <Maxtor 71050 AT>
wd0: drive supports 16-sector pio transfers, lba addressing
wd0: 1006MB, 2045 cyl, 16 head, 63 sec, 512 bytes/sect x 2062126 sectors
wd0: drive supports PIO mode 3, DMA mode 0
lpt0 at isa0 port 0x378-0x37b irq 7
wss0 at isa0 port 0x530-0x537 irq 10 drq 0: AD1848J
audio0 at wss0: half duplex
pckbc0 at isa0 port 0x60-0x64
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
opms0 at pckbc0 (aux slot)
pckbc0: using irq 12 for aux slot
pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
sysbeep0 at pcppi0
isapnp0 at isa0 port 0x279: ISA Plug 'n Play device support
npx0 at isa0 port 0xf0-0xff: using exception 16
WARNING: Pentium FDIV bug detected!
fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB, 80 cyl, 2 head, 18 sec
isapnp0: no ISA Plug 'n Play devices found
biomask c840 netmask ca40 ttymask dac2
boot device: wd0
root on wd0a dumps on wd0b
root file system type: ffs
de0: enabling 10baseT port
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