I have a LAN at home, with an assortment of computers; in particular,
an iMac and a 486DX/66 running netbsd-current of about a month ago.
When I try to copy files over Ethernet from the iMac to the NetBSD
box, it transfers several Kbytes then hangs; after a long time, it
spews a few more K and hangs, and so on.  When this happens, the input
error count for my Ethernet interface goes up by between 5 and 10 (or
so, a different number of errors each occurrence).  Transfers from the
NetBSD box to the iMac are no trouble at all.

This looks a lot like the iMac is blasting out back-to-back packets
and overrunning something on the NetBSD box.  I don't seem to see the
same problems between the iMac and a Performa, but that's using
Apple's EtherTalk and AppleTalk file sharing, which is known to be 
fairly ponderous.

Any ideas on how to sort out what is happening?  Is NetBSD advertising
a bigger window than it can really handle, or is the iMac blasting out
more data than it has been told to?  (Alas, I don't have an ethernet
monitor, so I can't capture a trace and find the culprit that way...)


Here is the dmesg output for my system.  The iMac, of course, is
pretty standard. ;-)

NetBSD 1.3G (JFW) #40: Sun Aug  9 23:59:09 EDT 1998
    jfw@jfwhome.funhouse.com:/usr/src/sys/arch/i386/compile/JFW
cpu0: Intel 486DX (486-class)
real mem  = 25100288
avail mem = 21876736
using 332 buffers containing 1359872 bytes of memory
mainbus0 (root)
isa0 at mainbus0
change bus timing
aha0 at isa0 port 0x330-0x333 irq 11 drq 5
change bus timing
aha0: model AHA-1540A/1542A/1542B, firmware 0.5
aha0: async, parity
scsibus0 at aha0: 8 targets
sd0 at scsibus0 targ 0 lun 0: <QUANTUM, LIGHTNING 730S, 241E> SCSI2 0/direct fixed
sd0: 699MB, 3658 cyl, 4 head, 97 sec, 512 bytes/sect x 1431760 sectors
sd1 at scsibus0 targ 1 lun 0: <QUANTUM, VP32210, 81H8> SCSI2 0/direct fixed
sd1: 2103MB, 4243 cyl, 8 head, 126 sec, 512 bytes/sect x 4308352 sectors
sd2 at scsibus0 targ 2 lun 0: <QUANTUM, FIREBALL1280S, 630C> SCSI2 0/direct fixed
sd2: 1222MB, 4135 cyl, 4 head, 151 sec, 512 bytes/sect x 2503872 sectors
sd3 at scsibus0 targ 3 lun 0: <IBM, DORS-32160, S82C> SCSI2 0/direct fixed
sd3: 2063MB, 6703 cyl, 5 head, 126 sec, 512 bytes/sect x 4226725 sectors
st0 at scsibus0 targ 5 lun 0: <CONNER, CTT8000-S, 1.17> SCSI2 1/sequential removable
st0: drive empty
com0 at isa0 port 0x3f8-0x3ff irq 4: ns16550a, working fifo
com1 at isa0 port 0x2f8-0x2ff irq 3: ns16550a, working fifo
com2 at isa0 port 0x3e8-0x3ef irq 5: ns8250 or ns16450, no fifo
lpt0 at isa0 port 0x278-0x27b: polled
we0 at isa0 port 0x300-0x31f iomem 0xcc000-0xcffff irq 10
we0: WD8013EPC Ethernet (16-bit)
we0: Ethernet address 00:00:c0:9a:8c:70
pas0 at isa0 port 0x388-0x38b irq 14 drq 6 ProAudio Spectrum 16Basic [rev 63, asic 4]
audio0 at pas0
midi0 at pas0 <PAS MIDI UART>
pcppi0 at isa0 port 0x61
spkr0 at pcppi0
sysbeep0 at pcppi0
npx0 at isa0 port 0xf0-0xff: using exception 16
pc0 at isa0 port 0x60-0x6f irq 1: color
pc0: console
fdc0 at isa0 port 0x3f0-0x3f7 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB, 80 cyl, 2 head, 18 sec
fd1 at fdc0 drive 1: 1.2MB, 80 cyl, 2 head, 15 sec
biomask 840 netmask c40 ttymask c42
boot device: sd0
root on sd0a dumps on sd0b
root file system type: ffs