Dec Pdp11

Would anyone know how to interface to one of these dinosaur?
I need to transmit a file to it from my Windows OS server. What sort of harware and software/driver is needed?
Thanks in advance.

good lord, i last worked on one of those in 1983. i haven't seen one since either. I believe the OS was RSX-11 or something like that. I bet there is a user group that you could find on google that still messes around with those "furnaces".

Don't make "silly" on the PDP-11.

The PDP-11 virtually defines a "solid system"... heavy stress on "solid".

PDP-11 came from DEC, Digital Equipment Corporation (Massachusetts).

That company virtually established the way that most of us operate computers today.

There were two ways at the time... the DEC way and the IBM way.

Thank God, at least in some cases, the DEC way prevailed. There were, however, some that followed IBM-think... that would be HP-think... and that would be AB-think (although, I have to admit, AB is coming along, kicking and screaming, to the DEC/TI way of thinking). HP still can't come to "human-terms". Apparently a Red-vs.-Blue thing.

I don't know if TI was driving DEC or DEC was driving TI, but, between the two, they came up with the ideal human-machine connection. GE followed right along with TI except GE, for whatever reason, decided on some weird element designations. (If you're used to the GE designations, fine. But, think about it.)

DEC was the first company to think of the human/computer relationship in "human terms".

After all, computers should be meant to serve humans... not the other way around. Ya think?

They (DEC) were the guys that came up with "pointers", as in "@"... gee, how much sense does that make?

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Terry Woods said:

Thank God, at least in some cases, the DEC way prevailed. There were, however, some that followed IBM-think... that would be HP-think... and that would be AB-think (although, I have to admit, AB is coming along, kicking and screaming, to the DEC/TI way of thinking). HP still can't come to "human-terms". Apparently a Red-vs.-Blue thing.

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curious viewpoint...in the 70's and early 80's A-B were virtually exclusively DEC and PDP-11. Then they built a VAX to share the back-plane with a PLC-5/250. Heck, they even adopted Ken Olson's matrix management system - just about the same time that DEC abandoned it.
And then DEC was absorbed by Compaq which was in turn absorbed by HP...

but to get back to the original question - I think a serial link would be the way to go.

And just to confuse things, Compaq was founded by a bunch of ex TI people ...

As far as I can remember all the various flavours of PDP11 had a serial interface, so the physical transmission of the data as ASCII is no problem. More likely to be a problem is whether or not provision has been made in the original software to transmit the data you want in this way. Most systems built before the mid-80s, when the first DCS systems started being built, would have no provision for this (although many may have been modified since).

@jstolaruk

You won't find many systems of any size using RSX11 - the main negative thing you can say about DEC S/W is that it was too much like Windows, in the sense that it tried to be all things to all people and as a result was far too slow. I remember Dutch State Mines experimenting with RSX11 in the mid-70s and the maximum they manged was four loops on 1 sec. scans. The Kent K90s, with their proprietary OS, were cable of handling over 500 loops on the same hardware!

I've got three K90 systems still running that I installed in 1980-81, the fourth was replaced about five years ago with PCS 7 V4 - it took Siemens nearly two years to get it running!

@DaveW

If you have problems with driver S/W come back with full H/W and S/W details. If the data is important enough to be worth the cost, I've still got contact to some friends who developed the S/W to link the above mentioned K90s to the outside world in the mid-80s. Even if it's a proprietary OS, if there's enough documentation available, they may be able to help.

Hmm, I just recall using a VT100 or maybe a VT50 terminal to access it. Maybe it wasn't an PDP-11 maybe it was a PDP-8 (was there such an animal?).

I yield to those with more experience; it stretches the gray matter to think back that far. But I'm betting there are some user groups that still play with these things lovingly and that would go out of their way to tell you everything you need to know.

DaveW said:

I need to transmit a file to it from my Windows OS server.

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Just one file ? Use a floppy disk.

More details please. Text / binary file ? How big ? How often ? What compilers do you have on the -11 ? Do you know PEARL ? X-modem was common on -11's.

In any case, an easy way is to connect a serial line to it, write a program on the WIN server to log on to the -11, open a text edit / X-modem sesion and send the file that way.

Is it a plain old -11 or a MicroVax like a 11/70 ? If so you might have DecNet (Pathworks) or other networking in it.

jstolaruk said:

Maybe it wasn't an PDP-11 maybe it was a PDP-8 (was there such an animal?)

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Yes, many flavors of 8's were made: -8, -8S -8L ...

maybe it was a PDP-8 (was there such an animal?).

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Yup, that was a 12 Bit predecessor, but it was nothing like the breakthrough that the PDP11 was.

Oops, hadn't noticed that somebody beat me to it! I'll crawl back into my hole then.

Is it a plain old -11 or a MicroVax like a 11/70 ?

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The 11/70 was a classic PDP11, the MicroVaxes, if I remember correctly, never actually carried the PDP11 name. Maybe your mixing it up with the VAX 750 / 780 etc. I don't think many people ever used the VAX in DCS systems, the development costs would have been enormous and the PLC movement was already getting under way.

However, you're right that we need a bit more information before we can give much useful help.

The 11/70 was a classic PDP11, the MicroVaxes, if I remember correctly, never actually carried the PDP11 name. Maybe your mixing it up with the VAX 750 / 780 etc. I don't think many people ever used the VAX in DCS systems, the development costs would have been enormous and the PLC movement was already getting under way.

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You're right - I was mixing and matching numbers / PDP / Micro / Vax. Too many, too long ago.

Just checked, it's a MicroPDP-11/73 that I have in the basement. It was used as a SCADA / OIT / recipe downloader to a packaging machine that used a AB 2/17 plc. We replaced the the MicroPDP-11/73 with a CTC P1 touch screen HMI and they gave me the computer as it was destined for the scrap bin.

Thankyou all for replying. Basically, our plant have 5 of these DEC PDP11 that control and reports for some of our equipment. We have decided to upgrade the first of the 5 PDP11 to Windows HMI/SCADA and PLC control system. The conversion is straight forward but we've found that this first PDP11 periodically is transfering a status file (I think it's ASCII but will have to check) to one of the other PDP11. So our question is how would we go about doing this with Windows.

Here's some more info I found on the existing PDP11.

The DEC PDP 11/84 IRV44 systems operate under the DEC RSX-11M-Plus operating system, version 4.6.

The DEC PDP 11/84 IRV44 computer system supports the transfer and receipt of data using the LAT/DECNET network protocol or direct cable link.

Desktop computer systems (PCs) access the DEC PDP 11/84 IRV44 through the LAT/DECNET network using SmarTermÒ terminal emulation.

Hi,


I did exactly this about 10 years ago. I am not sure of what type of PDP. We hired a PDP11 specialist(expensive) to make a program that transmitted a file to us after a batch was finnished. It seems that you already have this done and this is probably the hard part.

I wrote a simple PC proram in Superbase(BASIC) that read data from the RS232 port on the PDP. I remember that the baudrate etc was hardwired on the PDP. Try connect your PC with the hyperterminal. Experiment with baudrates etc and see what you get.

MRQ, thank you for replying. We actually want to do the opposite, transfer the file from the Windows PC to the PDP11. We're looking at some expert here in SoCal but like you said, they are expensive and a little hard to come by.

OK, sorry for not reading..........


The specialists where hard to get 10 years ago so I can imagine how it is today.

We're looking at some expert here in SoCal but like you said, they are expensive and a little hard to come by.

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As you say, such people aren't cheap, it depends on the importance of what you want to do, but I have 2 people here in Germany who may very well be able to help. To the best of my knowledge, however, they are not active in this forum (DCS company, PLCs are toys!).