jcd@pitt.UUCP (Jim Durham) (10/16/90)
I posted something about this before, but I have more info now, so thought I would try again... I have two Aviv SDZV cards (8 port serial multiplexers) in a MV II. At random times, the whole board (all 8 ports) locks up and seems even to effect the kernel. The only way to clear it is to reboot. Experimental Results: Hooking up the hardware handshaking lines makes no difference. Running at 600 baud or less works! (great, just great). Running Kermit thru the SDZV to another machine works fine at any speed, until you hit a process that doesn't understand control-s (XOFF), like Micro-Emacs (which maps control-s to search). Then it blows up while rewriting a screen. Apparently software handshaking solves the problem..sorta.. but its no good for SLIP. SLIP never works for long. Note: Dec dz(4) documentation mentions that DZ cards have 64 character silo buffers. However, they say that overflowing them while running a high-speed network doesn't do anything but lose a packet or two, which isn't serious. Questions: Is it possible that overflowing the buffers on the Aviv cards is much more serious? Perhaps locking up the whole card? Is there any way to do hardware handshaking in BSD? If I have to buy new boards, it's out of my pocket, so I'd just love to use what I have. Any ideas? -Jim Durham