From: Lawrence Stewart <stewart@serissa.com>
To: TUHS main list <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] Origins of PPP
Date: Thu, 5 Dec 2019 21:05:37 -0500 [thread overview]
Message-ID: <74614869-B858-40B0-B5CB-F806FD5CAEAE@serissa.com> (raw)
In-Reply-To: <698E9378-80A6-48F2-8B46-389B4A90ECD9@planet.nl>
At the other end of PPP history, I’ve always felt that the best part of IP is that it will run, more or less, over a piece of wet string.
In 2006 at SiCortex we were building a modest supercomputer with 972 six-core MIPS-64 chips connected by a rather nice high speed interconnect. The chips were booted over JTAG, which is another story, but in addition the chip had a “communications register” that could be written and read in I/O space from the kernel and over JTAG from the module level coldfire microcontroller.
This was at first used for the console, and all 972 console streams were collected on a front end machine. However, it was a small step from there to multiplexing the comm register to provide two serial ports. We used the second one for PPP using a standard driver on the MIPS end and a somewhat strange JTAG driver on the coldfire end. This scheme let us SSH into the machine nodes when the high speed interconnect needed debugging. In spite of the bit-banging JTAG-ness of it all, it was usably fast at 100 Kbps or so.
It was much easier to spin up PPP than to write a new network driver for this low-speed application.
-Larry
next prev parent reply other threads:[~2019-12-06 2:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-05 10:34 Paul Ruizendaal
2019-12-05 10:58 ` Michael Kjörling
2019-12-05 15:50 ` Richard Salz
2019-12-05 16:39 ` Clem Cole
2019-12-05 19:41 ` Warner Losh
2019-12-05 21:03 ` Clem Cole
2019-12-05 23:09 ` Doug McIntyre
2019-12-06 2:05 ` Lawrence Stewart [this message]
2019-12-06 18:31 ` Warner Losh
2019-12-05 19:05 Noel Chiappa
2019-12-05 19:21 ` ron
2019-12-05 19:37 ` Warner Losh
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=74614869-B858-40B0-B5CB-F806FD5CAEAE@serissa.com \
--to=stewart@serissa.com \
--cc=tuhs@minnie.tuhs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).