kvc@scgvaxd.UUCP (Kevin Carosso) (12/14/83)
This is in response to the query about the DMF-32 parallel port.
VMS does indeed support the parallel port. It works just fine.
I know of at least one site who use the DMF as their sole printer
interface. No problems at all.
Also, I believe we got some kind of a DMF-32 parallel interface look-alike
with our QMS laser-printer. We had to hack together a driver for
UNIX (4.1bsd), but this wasn't *too* difficult. Since we run VMS
systems too, the person who did the UNIX driver had access to the
VMS source listings.
As far as I know, it works just fine. If anyone is interested in the
driver, let me know and I'll point you to the right person.
/Kevin Carosso {allegra | decvax!trw-unix}!scgvaxd!engvax!kvc
Hughes Aircraft Co.sdyer@bbncca.ARPA (Steve Dyer) (07/10/84)
Sorry to be a noodge, but I find it hard to believe that no one out there
has any opinion (not to mention actual knowledge) of this issue.
Therefore, I repeat the question:
Can anyone comment on the advantages of purchasing an ersatz DMF32
(e.g., Able VMZ32) instead of the corresponding DH/DM clone?
As some of you have heard, I am trying to configure several VAX systems,
and the advantages of one over the other of these terminal multiplexers
is beyond me. Also, comments on the DZ11/KMC combination are welcome, too.
For background, 20-25 active terminal lines at 9600 baud in a software
development enviroment.
Ah, for the good old days when only a DH-11 was reasonable...
--
/Steve Dyer
{decvax,linus,ima}!bbncca!sdyer
sdyer@bbncca.ARPAgwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (07/10/84)
The KMC11B/DZ11 combination is terrific, but I have not heard of a 4.2BSD version being made generally available yet. Anyone know to the contrary?
henry@utzoo.UUCP (Henry Spencer) (07/11/84)
Opinions you want, opinions you get:
~DMF + Dec software supports it.
+ Trendy.
- New, so not as well-understood as DHs.
- Software can thus be expected to have flaws and maybe performance
problems as well.
- The hardware manufacturers may not have shaken their DMF lookalikes
down as well as the DH ones yet.
~DH + Well-understood.
+ Lots of software support with the bugs worked out.
+ Lots of field experience, hardware likely to work well.
- Not supported by Dec software very much any more.
- Old design, could be improved. (Not clear the DMF represents
an improvement, though.)
DZ+KMC + All Dec hardware, so few maintenance worries.
+ AT&T likes it.
+ Programmable, so software interface is (in principle) changeable
to suit your whims. In particular, much of the terminal
driver could be moved into the KMC to offload the main cpu.
(Don't know how far the AT&T code goes on this.)
- Fair bit of extra bus traffic, because the KMC has to poll the
DZs regularly.
- The KMC is a weird beast and there may be Unibus problems.
- Programmability is offset by the KMC being horrid to program.
My personal (prejudiced) opinion is that I see no reason to buy anything
but DHs unless you have some sort of special situation. If you must have
Dec software (e.g. you run VMS part of the time), DMFs are probably the
thing to have. If you must have all-Dec hardware, Dec DMFs are probably
the thing to buy. Now that the DMF is available, the DZ+KMC combination
doesn't seem a good buy unless the offloading/programmability issues are
a big win for you. I don't think any of these devices has a really big
performance advantage over the others.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henrygwyn@brl-tgr.ARPA (Doug Gwyn <gwyn>) (07/15/84)
The KMC11 is not at all horrid to program, if you use the software supplied with every AT&T UNIX release since System III. The source language is very like C, and about all that one would want to do is to make some very slight changes to the distributed source code, which is a lot easier than writing the whole driver. Most of the terminal driver was put into the KMC11, including input canonicalization and echoing. There should be no "Unibus problems" with the KMC11B. It can and does serve as a bus master, but so what? That is part of the Unibus design. I used to have a display processor (VR48) that was a second Unibus master; it worked fine.
henry@utzoo.UUCP (Henry Spencer) (07/20/84)
Some comments on Doug Gwyn's comments: > The KMC11 is not at all horrid to program, if you use the software > supplied with every AT&T UNIX release since System III. ... Quite right. What I should have said was, roughly, "the KMC11 is horrid to program, unless you have the AT&T software package, and AT&T has packaged it properly and it's all there and working, and it is really suitable for your particular needs". The reservations in that don't indicate bad experiences, just paranoia. > There should be no "Unibus problems" with the KMC11B. It can and > does serve as a bus master, but so what? That is part of the Unibus > design. ... Of course having other bus masters works fine... *if* the things are designed right. Some aren't. People I consider reliable have mumbled about things like bus hangs and having to make hardware mods to KMCs to get them to run reliably. Perhaps these problems have been fixed, or were local to odd Unibuses like the 780's UBA. [It is a mistake to assume that all Unibuses are alike; they aren't. The Unibus specs permit a fair range of behavior patterns, and the only way to design boards that work on *all* Unibuses is to work entirely from the spec. Not all designers are conscientious enough to do this. Not even all Dec designers.] -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry
boylan@dicomed.UUCP (Chris Boylan) (07/21/84)
Does anyone have the DZ/KMC-11 code from SIII/SV working under
4.2bsd?
--
Chris Boylan
{mgnetp | ihnp4 | uwvax}!dicomed!boylan