DEC DMF32 driver (Really: DMF vs. DZ11 vs... and UUCP)

[Alan Wu]

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Regarding the DMF32 driver, someone at 'harvard' has been running with
them under 4.2 or 4.3bsd for at least several months.  You might try
contacting 'sasaki at harvard'.

My question is which serial async interface to get for our VAX-11/750 running
4.2bsd, soon to be 4.3bsd.  The choices available seem to be the DZ11, DMF32,
DHU11, and a bunch of third-party emulators.  We already have 8 DZ11 lines
and need to add 8 more lines very soon.  As usual, we are on a tight budget.
The DZ11 board would cost us about $800, and the DMF32 would be about $2200.

Our machine (mit-eddie) has a large amount of UUCP traffic going through it,
both mail and News feeds, via 2 1200-baud async modems on the DZ11.  We 
have observed (in fact, it's hard to avoid noticing) that the system gets
excruciatingly slow whenever one or both UUCP's are fired up.  I'm not 
sure to what extent the DMF or other interfaces would have an advantage
over the DZ11.  (The DZ11 produces an interrupt for each character input
or output, whereas the DMF has DMA output and a silo on input).  Any insight
into possible benefits / lack of benefits from getting a fancier interface
would be appreciated, as well as any suggestions on how to determine what
the other bottlenecks in our system performance might be.  I am quite
familiar with VAX hardware and VMS (no flames ;-) tuning, but I'm still
coming up to speed on Unix tuning.  Pointers on where to look would be
appreciated.

By the way, we are running with 2MB of the old 16K-chip memory.  We are
working on getting the funding for an upgrade to 4MB of 64K-chip memory.
Is this likely to be enough?  Besides the heavy UUCP traffic, we have
maybe 2-6 interactive users.  No database stuff.  Two Eagle disk drives
on an Emulex controller.  Possibly will transplant 2 RK07 disks (already
paid for long ago...); one for quick data interchange, the other possibly
as a dedicated swap disk.  Have a Cipher 1600bpi streamer magtape on
a Dilog D132 controller, may possibly get a MassBus Adaptor and a dual
port kit to share a forthcoming  TU78 magtape drive on a nearby machine.

I will summarize to the net if I get any helpful responses and if there
seems to be any interest.