henry@utzoo.UUCP (Henry Spencer) (07/21/83)
Does anybody have good/bad/indifferent comments on the Emulex CS11/H
DH lookalike? We are seriously considering getting one to replace a
bunch of DZs. The Able DHDM is the alternative, but we are tight for
both backplane space and cable-routing space, so the ability of the
CS11/H to run 64 lines from a single board is very attractive. Our
machine is an 11/44 running V7 with a fairly orthodox timesharing load.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henryhenry@utzoo.UUCP (Henry Spencer) (08/16/83)
A while ago I asked for comments on the Emulex CS11/H DH lookalike.
We were interested in it as an alternative to Able DHDMs, since we
need to replace some DZs but are short of backplane space and cable-
routing space. The following is a summary of the responses I got.
(For those who aren't aware of it, the Emulex CS11/H is a single
Unibus board which emulates up to four DHs. Most of the per-line
hardware is out in the distribution panels, and the board is just
basically the Unibus interface. There is *one* cable running out
of the board, and the distribution panels are daisychained together.
Also, although it is not of interest to us, one can get distribution
panels that speak current-loop (or whatever) rather than RS232.
Prices are competitive with the Able DH, and probably in fact better
if you are buying lots of lines. The Berkeley configuring-a-VAX
document spoke well of the CS11, but I thought I'd ask anyway.)
Overall reaction was highly favorable; I got a number of comments
that basically just said "we use them, they work fine, we like them".
The following are comments with information content other than that,
with identifying details deleted since I didn't originally specify
that I'd be publishing replies. They should, of course, be understood
to be the personal opinions of their authors.
-----------------------------------------
We've got three of the CS11/H beasties running on our systems - one CS11/H1
on an 11/70 supporting 48 lines, and a CS11/U2 supporting 64 lines on each
of two Vax 11/780s. We have had no problems with them that couldn't be
traced to sources other than the CS11 (e.g., one got zapped when our Physical
Plant people decided to try the circuit breakers in the building, etc.); in
fact, we have just purchased two more CS11/U2 systems for our Vaxen. The
64 lines/board feature is very nice; anytime you can save seven Unibus slots
(one board vs. eight, for DZs) is great. On those occasions when service is
required (EXTREMELY infrequently), we've gotten great response from Emulex
(overnight air shipment, reasonable prices for the stuff that's out of
warranty, etc.) I recommend them whole-heartedly.
-----
We used these at [...] with good success. Note that there are
several Emulex DH11s; you need the /V model for the VAX-11/780 at
least, due to a not-quite-Unibus on the /780. Look at the model
numbers and specs closely to be sure you get one that works with
your particular CPU/backplane.
-----
We decided on the Emulex CS11/H2 for the same reason you proposed:
saving hex slots on the backplane. So far I have been very pleased --
installation was a snap (except for the interpretation of what "open"
means on a dip switch -- it turned out to be the opposite of what you
would expect), and it has worked flawlessly since. We have 32 lines
on one Vax and 16 on the other. I believe we paid $5400 for the 32
lines, which was pretty good (cheaper than Able). We also have a
couple of Able DHDM's and they are also excellent, but if you want more
than 16 lines, you probably should go with Emulex.
-----
Do not buy one. We had one on our pdp 11/70 and it ran absolutly fine.
Then one day, Unix started crashing. I called DEC's remote diagnostic
center and they discovered that the problem was in the Emulex. Unix
would crash when it was testing the DM register of the Emulex. (Oh
yes, we have the 16 line version). The board was packed off to
Emulex but we informed [distributor] whom we had bought it from.
We were supposed to send it to [distributor] who would then mail it
on but we were given permission to mail directly.
Emulex got the board and informed us that they could find nothing
wrong. The did install 8 ECO's and were preparing to send it back.
They would charge us $950 for the ECO's and call it square. i asked
what the ECO's were for and was told that they would not tell me
due to company policy. If I told someone else that the ECO's were
available, they might want them too. (I did not make that up, thay
is what they said on the phone.)
A week passed. Another week passed. Suddenly, another week passed.
We phone Emulex to ask what happened to our board. The answer was
incredable..."It was damaged in shipment when they received it."
Talk about thivery!!! We informed them that we had been in
communication already with them, there was nothing wrong with the
board and we want it back now. I guess they were embarrased. They
sent us a new board and only charged us $450 for it rather than $950.
I doubt if that would have happened if they had not tried to lie.
I later talked to a [distributor] representative at the DECUS in
Ottawa. They now do not sell Emulex equipment [...]
The descision is still yours but if you do purchase an Emulex,
be sure you can fix it. Also, I have some real estate that you
might be interested in...
-----
I've got a 48 line cs-11 on my 11/780. Works like a charm. I've got 25'
cable between the cs-11 controller and the distribution boxes. This lets me
stick the distribution panels on an old cabinet directly adjacent to our
Micom port selector. This saves many bucks on cables plus keeps our
unibus cabinet free of junk (so we can stuff it full of Fuji Eagles).
I've heard random rumors of problems with 64 line cs-11s. I don't know
of any specifics.
The diagnostics are great. Both internal and external loopback tests
are built into the distribution panels. The panels are swapable in
8-line chunks.
-----
We have one CS11 in use for more then a year.
Our overall opinion of it is favourable, the UNIBUS
interface is reliable and never caused us any problems.
The terminal interface is somewhat less reliable then DEC DH11,
but definitily reliable enough for everyday use.
Our misgivings on the EIA drivers are :
1- The output drivers make more errors on long distance cable the those
of the DH11 ( we use cables of about 100 meters)
2- The input sensors sense a low input signal when left open, while DH11
input signals are considered high when left open. THis means you have
to connect CLEAR TO SEND and DATA TERMINAL READY to a positive signal,
the line doesn't react otherwise. You can use REQUEST TO SEND
for that purpose.
We use the CS11 under V7 UNIX on a PDP11/44.
-----
We are very happy with our CS11s. We currently have 8 of them. We chose
Emulex over Able because of the modem control support. The able board
supports no more than what is supported by a DZ. The Emulex supports
everything that a DM11 supports. This was very important because we
have most of our ports tied in to a local net which likes full session
control and CTS/RTS flow control. The Able board just didn't cut it.
-----
we have a 750 running 4.1Bsd. In march we replaced
three DZ11 (look-alikes) by one 48 line CS11. We have
had no problems whatsoever, hardware or software-wise.
The DH11 driver works without mods. The CS11 seems
pretty solid mechanically, and I very much like the
diagnostic facilities: each group of 8 lines can be
checked for internal operation, for internal operation
up to the line-drivers and for operation from the
terminal back to the line-drivers (thus allowing the
cables to be checked, a facility we very much
appreciate seeing as we have cables going through weird
convolutions all over our 20 floor building). The
diagnostic mode is switched from the front-panel (where
the RS-232 connectors are).
As you can see I rather like the CS11. Our maths
department also has a similar configuration and they
too have had no problems.
-----------------------------------------
In short, overall it looks pretty good. Only that one serious
negative note. I've mulled that one over for while, since the
guy who sent it is a friend of mine, but decided that the good
reviews from elsewhere and the technical advantages are strong
enough to justify chancing it. We're about to order one.
--
Henry Spencer @ U of Toronto Zoology
{allegra,ihnp4,linus,decvax}!utzoo!henry