DUP-11 vs. DUV-11

[David Herron, NPR Lover]

[All praise to the mighty line eater....  Please accept this sacr


Hi y'all!  I've just spent a few hours comparing the DUP-11 (Synch
board for Unibus machines) and the DUV-11 (Synch board for Q-bus's) and
I've got a few questions.  What is going on is that we have this "old"
11/750 with a DUP-11 which we're using to connect us up to BITNET.  We
also have these 4 "new" uVaxII's and we're very very very very pleased
with the performance on them.  Eventually the service contract costs on
the 750 will force us to replace it with something.  But we need to
remain attached to BITNET, meaning we either add a Synch port to one of
the uVaxIIen or have the replacement machine posess a Unibus.  (i.e. an
8xxx machine) (As an aside, is there a qualitative advantage to an 8xxx
machine over a cluster of uVaxII's?)

Now, with that as justification... The DUP and the DUV look very very
similar.  They have the same registers (though there are differences in
the actual bits), and the same sort of philosophy (i.e. very basic
synchronous interface).

The important difference seems to be in details about transmitting a
packet.  In the DUP-11 there are some bits in the TXDBUF register that
you set at special moments.  For instance, for the first character of
the packet you also set the TSOM bit, after the last character you set
the TEOM bit, and there's a couple more similar bits.  The DUV-11 has
NONE of those bits.  And, unfortunately, the manual I'm reading is a
"later" sort of DEC manual so it doesn't go into enough detail for me
to understand how it really works.  (I have the 1980 Microcomputer
Interfaces Handbook)

1) To send a packet out a DUV do you just light the SEND bit, wait
   for awhile while the DUV is idling synch characters out, then
   start shoving bytes into the TXDBUF register (waiting for TXDONE
   to light inbetween)?
2) The manual doesn't talk about doing lots of protocols like the DUP
   manual does.  And it doesn't throw around buzz-words like SDLC or
   ADCCP either.  Instead it says "internal synchronous", "external
   synchronous", and "isosynchronous".  It also mentions the word
   "bisynchronous support" at the beginning.

   What does that mean?  We're currently doing bisynch with ours
   to an IBM-308x.  I suppose that "bisynch support" means we can
   continue doing that if we get this board, however "support" usually
   means you have to do something a little strange (i.e. it's not
   what it was specifically designed for, however we left this
   hook so you can still do it but you gotta bend over backwards
   a little bit).
3) The DUV suffers from the same problem as the DUP.  That it is
   an INCREDIBLY DUMB board.  Is there a newer board that we can
   (or should) get?  (It'd be great if it were compatible with
   the DMF's synch port..)
4) Anybody have an idea when UREP V.3 will get out the door? :-)

advTHANKSance
-- 
David Herron,  cbosgd!ukma!david, david at UKMA.BITNET, david at ms.uky.csnet
	(I'm also "postmaster" at all those addresses)
	(And "news" and "netnews" and "uucp" and ....)