[TUHS] My BSDcan talk

[TUHS] My BSDcan talk

[Paul Ruizendaal]

> It's another similar to the last two. I've uploaded a version to youtube until the conference has theirs ready. It's a private link, but should work for anybody that has it. Now that I've given my talk it's cool to share more widely.
> The link at the end is wrong. https://github.com/bsdimp/bsdcan2020-demos is the proper link.
> Please let me know what you think.

Watched it & liked it a lot!

I have one nit-pick in the section on early networking: BBN's VAX TCP did not allow the ‘/dev/net/host’ syntax. That particular semantic comes from UoI’s NCP Unix, where the 8-bit host number was encoded in the minor number of character special file ‘host’ - but it did not carry through to the BBN code.

Other systems used something similar. The Chaos network code made namei() break when it recognised the Chaos driver and left the remainder of the path for the driver to fetch & parse. I’m also being told that Greg Chesson experimented with using the given name of a Datakit channel device as the connection string for the switch, but that this approach was abandoned early on.

In my view, exposing the host names through integration in the Unix file name space makes a lot of conceptual sense, but it unfortunately falls down on the practicalities, with the host name set being hard to enumerate (it is large, distributed and not stable - even back then).

A question mark is hard pin-pointing the start of Unix networking to V4 / 1974. Yes, that is the earliest evidence we currently have. However, Sandy Fraser says that Spider came into operation in 1972 and it must have connected to something. Maybe that something was a lab-bench test setup, but it could have been a computer - maybe even one running Unix.

There is another candidate for earliest Unix networking as well. The tech memo’s from Heinz Lycklama include one on the Glance terminal. That memo includes a section on the network used, referencing a 1973 report by D.R. Weller, "A High-Speed I/O Loop Communication System for the DEC PDP-11 Computer”. That computer appears to be an 11/45 running Unix and the loop is not Spider (nor the Pierce loop discussed in 1970/71 BSTJ). I have an off-list question outstanding to better understand this.

Re: [TUHS] My BSDcan talk

[Clem Cole]

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On Sat, Jun 6, 2020 at 10:56 AM Paul Ruizendaal <pnr@planet.nl> wrote:

> The Chaos network code made namei() break when it recognised the Chaos
> driver and left the remainder of the path for the driver to fetch & parse.
>
Yep - cute hack -- Domain (Aegis) did the same trick (same code author most
likely).  The biggest advantage is that open(2) can be used unchanged and
'parameters' are passed in ASCII to the lower code.

You mentioned that BBN Vax code did not use it.  I've forgotten than how
parameters like IP addresses were passed down?  I had thought that Rob had
is also in at least one version of the BBN code, as I remember talking to
him about it at one point; but I have frankly forgotten.   I'm pretty sure
that wnj thought it was an ugly solution; which is why UCB did not try it.

We played with this solution also in the early Masscomp networking code (I
had seen it in the Chaos driver from MIT); but by then the UCB code was
coming out and user code was using sockets, so we just kept with that
interface for code reuse reasons.

Clem

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Re: [TUHS] My BSDcan talk

[Andrew Warkentin]

On 6/6/20, Paul Ruizendaal <pnr@planet.nl> wrote:
>
> In my view, exposing the host names through integration in the Unix file
> name space makes a lot of conceptual sense, but it unfortunately falls down
> on the practicalities, with the host name set being hard to enumerate (it is
> large, distributed and not stable - even back then).
>
With a proper dynamic VFS architecture, there is no reason why a
resolver with a filesystem API has to bother supporting enumeration at
all. All it needs to be able to do is respond to open() and stat()
calls, returning ENOENT when resolution fails.

Re: [TUHS] My BSDcan talk

[Paul Ruizendaal]

> On 6 Jun 2020, at 18:01, Clem Cole <clemc@ccc.com> wrote:
> 
> You mentioned that BBN Vax code did not use it.  I've forgotten than how parameters like IP addresses were passed down?  I had thought that Rob had it also in at least one version of the BBN code, as I remember talking to him about it at one point; but I have frankly forgotten.

In the surviving source code, BBN VAX TCP re-purposed the ‘mode’ parameter of open() to be a pointer to a block with connection data (“struct con”). Details are here:
https://www.tuhs.org/cgi-bin/utree.pl?file=BBN-Vax-TCP/doc/net.5.P

Re: [TUHS] My BSDcan talk

[Warner Losh]

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On Sun, Jun 7, 2020 at 5:42 AM Paul Ruizendaal <pnr@planet.nl> wrote:

>
> > On 6 Jun 2020, at 18:01, Clem Cole <clemc@ccc.com> wrote:
> >
> > You mentioned that BBN Vax code did not use it.  I've forgotten than how
> parameters like IP addresses were passed down?  I had thought that Rob had
> it also in at least one version of the BBN code, as I remember talking to
> him about it at one point; but I have frankly forgotten.
>
> In the surviving source code, BBN VAX TCP re-purposed the ‘mode’ parameter
> of open() to be a pointer to a block with connection data (“struct con”).
> Details are here:
> https://www.tuhs.org/cgi-bin/utree.pl?file=BBN-Vax-TCP/doc/net.5.P


That's... clever? Gross? I don't even know how I'd want to react to
this...  which likely means "too clever for its own good" :)

In any event, I've created a short, 2:00 correction to my talk. I'll have
the conference organizers tack onto the end before they upload it to
youtube.

https://www.youtube.com/watch?v=9uTjyfO6MM8

If people care :)

Thanks everybody for corrections...

Warner

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[TUHS] My BSDcan talk

[Warner Losh]

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OK. Must be off my game... I forgot to tell people about my BSDcan talk
earlier today. It was streamed live, and will be online in a week or
three...

It's another similar to the last two. I've uploaded a version to youtube
until the conference has theirs ready. It's a private link, but should work
for anybody that has it. Now that I've given my talk it's cool to share
more widely...  https://www.youtube.com/watch?v=NRq8xEvFS_g

The link at the end is wrong. https://github.com/bsdimp/bsdcan2020-demos is
the proper link.

Please let me know what you think.

Warner

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