NetNews Usenet Archive 1992 #26/NN_1992_26.iso/spool/comp/sys/dec/5801

Internet Message Format | 1992-11-05 | 2.8 KB

Path: sparky!uunet!destroyer!gatech!concert!ais.com!bruce
From: [e-mail] (Bruce C. Wright)
Newsgroups: comp.sys.dec
Subject: Re: Q: What is a DUV11 ?
Message-ID: <[e-mail]>
Date: 5 Nov 92 11:43:04 GMT
References: <[e-mail]> <[e-mail]> <[e-mail]>
Followup-To: comp.sys.dec
Organization: Applied Information Systems, Chapel Hill, NC
Lines: 43

In article <[e-mail]>, [e-mail] (Alain Martineau) writes:
> In article <[e-mail]>, [e-mail] (Bill
> Laut) wrote:
>> If I remember correctly, the DUV11 was the Q-bus version of the DUP11, and
>> that card was used for doing bi-sync with IBM.  This was -way- before the
>> days of doing all of that IBM stuff using SNA bridges, etc.
>>
>> I think the card also could do DDCMP for a slower-speed DECnet link.
>>
>> The card is rather dated in terms of technology.  You can still plug it into
>> the Q-Bus, but I don't know if the drivers are still there in VMS to support
>> the thing.
>
> We have about 5 11/780 at my company with DUV11, and I think the guys
> responsible for them asked DEC to keep the driver in, and fix it to work
> with VMS 5.x.

I doubt it.  The DUV11 was a QBUS card, and the 780 had a UNIBUS.  You
probably either have a 780 with DU11 or DUP11 cards in it (which are
UNIBUS cards), or you have some MicroVAX (like a MicroVAX II) with the
DUV11 in it.  The DUV11 was very similar but not identical to the DU11
and DUP11 cards, implemented for the QBUS rather than the UNIBUS --
Bill's memory is essentially correct.  If you have a driver for any one
of those three cards (DU11, DUP11, DUV11), it would be trivial to modify
it for another;  in fact it would not be unlikely to be able to use it
unmodified.

BTW if you are thinking about implementing a sync communications
application on a QBUS machine, the DPV11 is probably a better choice
than the DUV11 because I believe it has a deeper silo than the DUV11 --
as I recall the DUV11 has only a 1-character deep buffer (receiver
buffer register + receiver shift register), while the DPV11 has a 4
character silo in addition to the receiver shift register.  (This is
from memory, I can't seem to find anything specific about this in the
device documentation.  I may be confusing these with other devices).
It's also rated for up to 56K baud as opposed to the DUV11's 19.2K
baud.  You'd likely get fewer data overrun errors on the DPV11.  Or,
if you can restrict your application to DDCMP, BISYNC, or SDLC/HDLC,
(the major but not the only sync protocols), you could use something
like the DSV11 card, which is a much nicer card (DMA support, for
example) if you can live with its restrictions.

Bruce C. Wright