Ultrix-11 Networking
Douglas Taylor
dj.taylor4 at comcast.net
Sun Aug 29 12:41:28 CDT 2021
On 8/28/2021 6:19 PM, Bill Gunshannon via cctech wrote:
> On 8/28/21 4:13 PM, Douglas Taylor via cctalk wrote:
>> On 8/28/2021 1:15 PM, Bill Gunshannon via cctalk wrote:
>>> On 8/28/21 1:03 PM, Douglas Taylor via cctalk wrote:
>>>> Yes, I did create a new kernel and copy it to the correct place and
>>>> chmod 644 the new unix file.
>>>
>>> Did yo have fun playing with the overlays? :-)
>>
>> I don't know what this means. The kernel creation was automatic, it
>> seemed to check for enough room.
>
> I guess you did the bare minimum to get the network up. When I buld
> a new kernel I tend to add all the devices (like multiple network cards
> and serial cards) that I may want in the future. I have often had to
> manually shift things around and usually create one or two additional
> overlays to get it all to fit. I actually enjoy doing it. :-)
I had only toyed with the idea of adding a dzv11 so real terminals could
be connected to a real pdp11 Ultrix-11 system. I guess I'll find out
once I get there.
>
>>
>>>
>>>> On my Debian system I can install ftpd and telnetd (they are still
>>>> in the Debian package list) which are the unsecure ones, but I
>>>> don't know how to configure them or start them. As in, # systemctl
>>>> restart ftpd
>>>
>>> Probably easier to turn them on on Ultrix-11. Just modify inetd.conf.
>>> Actually, I just looked and ftp is on by default. Telnet is not.
>> I edited inetd.conf to uncomment telnet. It helped.
>>>
>>>>
>>>> It turns out to not be a hot topic: "How do I make my Liinux system
>>>> less secure?", but for us that noodle around with old computers
>>>> with obsolete operating systems it is exactly what we need. In the
>>>> past I remember using Filezilla to go from a Windows7 machine into
>>>> a Vax without any problem.
>>>
>>> I suspect you will be somewhat disappointed with networking in
>>> Ultrix-11. Not that there is something wrong with it, just that
>>> the hardware is nothing like you are used to. In the early days
>>> of networking it was not unusual for systems like the PDP-11 to
>>> crash just because of the traffic passing by on their network
>>> connection. The advent of switches helped alleviate that but it
>>> is still common to crash a system by pushing data at it from a
>>> modern ftp. I expect FileZila will do it. To be honest, I always
>>> preferred Kermit for moving files. It is possible to keep packet
>>> sizes down and even slow down the transfer rate to give the PDP
>>> time to handle it.
>>>
>>> bill
>>>
>>>
>>>
>> I brought up a Vax Alpha 3000-300 and tried interacting with the
>> Ultrix-11 simulation:
>>
>> Starting in Ultrix-11 I could log into the vax via telnet. Ultrix-11
>> ftp was able to transfer a short ascii file from the Vax to the
>> Ultrix-11 sim.
>
> Just another note. remember that ulimit is only 1024 on Ultrix-11 by
> default. That means no file larger than 10M. Unless you raise ulimit.
>
>
>>
>> Going the other way, Ultrix-11 would reject an ftp request from the
>> vax, here is the error message -
>>
>> $ ftp 192.169.0.52
>> %TCPIP-E-FTP_NETERR, I/O error on network device
>> -SYSTEM-F-UNREACHABLE, remote node is not currently reachable
>> $
>
> Been a long time. Could have to do with PTYs. Remember, FTP takes two
> open connection and the number of possible connection on Ultrix-11 is
> very limited.
I think I noticed that I only had 2 PTY's during the install/kernel
process. Glad you mentioned this, it had gone over my head.
Ignore the VAX error, the error was mine. I typed the ip wrong, should
have been 192.168.0.52, not 192.169.0.52. Blame it on bad eyes, old
age, small font, clumsy fingers.
>
>>
>> Ultrix-11 would allow a telnet connection (after the change to
>> inetd.conf) and I could do an ls, but when I asked for a man page it
>> hung up. Nothing after that, had to kill it.
>
> I told you it was very unstable. :-)
>
>>
>> I got the same result whether I was telneting in from the Vax or
>> Linux computer. Probably not news to you. I wonder if real hardware
>> works just like this....
>
> Sometimes, but I always found SIMH less reliable with my limited use
> of it. I always preferred real hardware.
>
>>
>> It was good to find out that you can get things in/out of the
>> Ultrix-11 simulation.
>
> Like I said, I usually find Kermit over emulated serial lines to be more
> efficient at moving stuff on and off. The network may be faster but
> failures after 4 hours of a transfer can be very frustrating. Better
> to let kkermit have it over night and then get a fresh start in the
> morning.
>
> bill
>
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