[HECnet] Announcing TCP/IP for RSX-11M-PLUS

Johnny Billquist bqt at softjar.se
Thu Jan 22 10:47:48 CST 2015

I just thought I'd make yet an announcement.
(Maybe I should find a better forum for this?)

The last week I've been busy with FTP improvements and performance, and 
I've managed to improve this a lot.
Enough that it is worth sending information out that people should 
upgrade if they have installed this.

The FTP client and server have improved performance and some additional 
features. Along with this I also changed the protocol format for RSX 
special mode transfers. This is not backwards compatible, and due to an 
initial design miss, the old ftp client/server will not reliably detect 
this incompatibility, resulting in broken files if RSX mode is used 
between the old and new version. This will not be a problem going 
forward. If you run FTP from RSX to fetch the new package, use BLOCK 
mode instead of RSX mode, and fetch the disk image and not the tape 
image, and you'll be fine. Once upgraded, RSX mode is definitely the 
recommended mode for the future. For all kind of files.

TCP itself increased the receive buffer size, which also improves 
performance for everything that would be interested in higher throughput.

I've also gone over the distribution and installation scripts and fixed 
a few minor details.

As usual, the distribution is available from:

The documentation is also available through ftp on Madame, or also at 


All in all,
On 2015-01-16 04:47, Johnny Billquist wrote:
> There have been lots of positive comments, and obviously some people
> have even tested using the software.
> Of course, a bug was also found. A really weird corner case with
> severely loading the network stack and having a socket in listen state
> programatically could trigger a corruption of kernel memory.
> So I've cut a new release with the bug fixed.
> While I'm at it I also realize that I forgot to mention that included in
> the distribution is also a simple IRC client as well as a simple IRC robot.
> I've also taken a little time to slightly improve the documentation, and
> the documentation is now also available directly by ftp from
> Madame.Update.UU.SE, so you do not need to get the whole distribution
> and unpack it to just read something.
> So - same as before. Disk image and tape image are available at
> Madame.Update.UU.SE. Use anonymous ftp.
> Disk image is also available at ftp://ftp.update.uu.se/pub/pdp11/rsx/tcpip.
> The disk image is a virtual RL02 disk. Can be used with any emulator, or
> also directly inside RSX if you have virtual devices available.
> Happy hacking.
>      Johnny
> On 2015-01-14 00:40, Johnny Billquist wrote:
>> Well, it's been a long time project, but I'm happy to finally announce a
>> more public initial release of TCP/IP for RSX-11M-PLUS.
>> This is the result of over 20 years of development. Needless to say,
>> I've been doing a lot of things over the years, and this code have been
>> through four reimplementations over the years.
>> What I now release is something that I believe is a nice and useful
>> piece of software. I am aware of the fact that most people do not use
>> these machines any longer, but if someone actually wants to talk to me
>> about support for this or other RSX software, let me know.
>> Also, feel free to spread this information to anyone who might be
>> interested, anywhere.
>> So - what is in this release?
>> It is a complete implementation of ARP, IP, UDP, and TCP for
>> RSX-11M-PLUS. It has been tested on RSX-11M-PLUS V4.6, but should work
>> on any V4 release. There might be some small tweaks or fixes required,
>> but nothing major.
>> It do require a system with split I/D-space, or else at least the TCP
>> part will not fit.
>> For Unibus machines, it should be possible to run without any additional
>> software except what is in a base RSX distribution.
>> For Q-bus machines, DECnet is required for ethernet networking.
>> The TCP/IP stack can co-exist with DECnet.
>> Some utilities also utilize RMS for file access.
>> A bunch of tools, utilities and libraries are also included. These
>> include:
>> . IFCONFIG network configuration tool.
>> . NETSTAT network information tool.
>> . PING
>> . DNS client
>> . FTP daemon
>> . FTP client
>> . HTTP server
>> . TELNET client (rudimentary)
>> . TFTP client
>> . TFTP server
>> . INET server that can do SINK, ECHO, DAYTIME, QUOTE, and IDENT
>> . NTP client
>> . LPR client that sits in the queue manager (rudimentary)
>> . FORTRAN-77 library
>> . BASIC+2 library
>> . PDP-11 C library
>> The implementation fulfills most of the requirements put forth in RFC
>> 1122. There are a few limitations because of restrictions in the PDP-11,
>> but none of them should really cause any problems.
>> Documentation is still on the thin side, but example configs are also
>> provided, along with installation scripts.
>> A bunch of test programs and example programs are also included, as well
>> as the sources of all tools and libraries.
>> The TCP/IP stack itself only comes in binary form.
>> All tools are also included precompiled in the distribution, so an
>> installation only have to build the stack itself for your system, and
>> then you should be ready to go.
>> The API only have a slight resemblance to the Unix sockets API. However,
>> if someone sits down to write code to use TCP/IP under RSX, I'm sure
>> they will discover that it is extremely easy to use the libraries, or
>> the basic functions.
>> The TCP/IP implementation is mostly written as device drivers. This also
>> have some other interesting implications, such as it is possible to
>> access TCP as a normal file. You can, for instance do something similar
>> to the Unix netcat command by issuing the MCR command:
>>  > PIP TI:=TC:"foo.com";4711
>> which would open a connection to foo.com, on port 4711, and any data
>> sent from that machine will be shown on the terminal.
>> The resources used by TCP/IP are modest. A memory area (size selectable
>> at generation/startup) is used internally. The amount of memory in the
>> private pool limits the amount of data that can be buffered. Normal pool
>> is used in a small quantity for each TCP port that is open.
>> People are welcome to play around with this, and make improvements.
>> Contributions of code is most welcome.
>> There are still lots of things to do. The programs marked as rudimentary
>> should be rewritten.
>> The most obvious thing still missing is a telnet daemon, which probably
>> is my next step.
>> However, the reason for now announcing the release is that it can
>> finally be distributed natively from an RSX host.
>> The main locations to download the TCP/IP for RSX are:
>> Madame.Update.UU.SE (anonymous ftp).
>> This is one of my development systems for this software. It runs under
>> E11, and if things are down, I blame E11. :-)
>> When connected, you are already in the right directory. There is both an
>> RL02 disk image there, which can be downloaded by anyone. If you happen
>> to have an RSX system which you are conneting from, you can also try
>> getting the BQTCP.TAP tape image. Such an image will not transport
>> cleanly to a non-RSX system, however. Sorry.
>> ftp.Update.UU.SE (anonymous ftp) - /pub/pdp11/rsx/tcpip
>> The disk image is normally duplicated to ftp.update.uu.se as well, so
>> the same file can be found there.
>> I hope some people will find this useful/amusing. :-)
>>      Johnny Billquist

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