From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 0cb63e73 for ; Fri, 6 Dec 2019 18:31:44 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id AD5EE9BFB3; Sat, 7 Dec 2019 04:31:43 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id DB5C194BF4; Sat, 7 Dec 2019 04:31:25 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=bsdimp-com.20150623.gappssmtp.com header.i=@bsdimp-com.20150623.gappssmtp.com header.b="drhhAXJ8"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 79FDD94BF4; Sat, 7 Dec 2019 04:31:23 +1000 (AEST) Received: from mail-qt1-f176.google.com (mail-qt1-f176.google.com [209.85.160.176]) by minnie.tuhs.org (Postfix) with ESMTPS id E346993D35 for ; Sat, 7 Dec 2019 04:31:22 +1000 (AEST) Received: by mail-qt1-f176.google.com with SMTP id j5so8006522qtq.9 for ; Fri, 06 Dec 2019 10:31:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=gCXkwRigc0QpffhcHzFzF6lcXdR+vjjrS5Mo2kLtTVI=; b=drhhAXJ8jUH3q1T2EdO8CABBuJH3t1u0enSeq00lXCGhS94OgDB6weo0ji+1XeJiV8 sIKw99lQY9cu/0Q+Wxe3HR7ZMVUPHES4FGMBOpwVPtBwFeADBdjhtnpAIaMi9/qE0kWX 2vJnotcu1WLxyPM6EhEg8b6YqRV8rlXOeFt8bjOxXyYM1bUqwW6fbRuraa7eD16Lzgap OOUc8szib/y6vq7XhLHDNXffNbdyTUf9LlPyX2mEHBgMfA485+xhUB1tku0R8hYS9HHO kU73tuxyF3rOYYQ/lhgwq5/tSaYviP8Uq90mX7er0/K97GlZWoXXH/OSmJqfH4DMd8ZR 6W7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=gCXkwRigc0QpffhcHzFzF6lcXdR+vjjrS5Mo2kLtTVI=; b=VGB/Dccfkrx6lbTdde/1T0byG8aniuN4LKBv/p26/LaBF6mTN/00yjOTpZG4uRtQS+ lDrjgYwH2LChk9YWaCAXC68M9iPA7Qct85W6YoKKwbz+rrDPIsY/hzX3lFetYXYIhCSd ME1tCJ0fbCbHFJjEzHp3jjiJFRXwGo/VFfzMp6n5xL1ZNdJbk6Sw8Px6MbqjbVraW64P BsRXdpvpOcfH9i8fVcaVDLig70dIn5YXB/Lk6eGDkiAkW1HNYSiXmsMBap90tQ+DJD4I UCTc/wDKdPSIH/AZ3kbwbLWrqCFzYzkJPIu5Nfba82p+ffS/vApgxqryGorWYcMty/Rk PV/Q== X-Gm-Message-State: APjAAAVFnCAJRNzM80aQIMaUvw6yxV0ijVTdFVy9zHLYMqqNtvylLsor i93yDHQD3WXqYNHSMUA8ahuHaGYdOBtFniy4SUjBzXbNNj8= X-Google-Smtp-Source: APXvYqy3YUEwYM19aXVwBu9cBRKT8PP0An8hn2uTxHEPWLC4iLM/o3puoxHxH5QGICHBnNhCtfuYwgzpC1lgQJx6Kbo= X-Received: by 2002:ac8:7198:: with SMTP id w24mr13398611qto.32.1575657081940; Fri, 06 Dec 2019 10:31:21 -0800 (PST) MIME-Version: 1.0 References: <698E9378-80A6-48F2-8B46-389B4A90ECD9@planet.nl> <74614869-B858-40B0-B5CB-F806FD5CAEAE@serissa.com> In-Reply-To: <74614869-B858-40B0-B5CB-F806FD5CAEAE@serissa.com> From: Warner Losh Date: Fri, 6 Dec 2019 11:31:11 -0700 Message-ID: To: Lawrence Stewart Content-Type: multipart/alternative; boundary="000000000000a8426005990d40e3" Subject: Re: [TUHS] Origins of PPP X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: TUHS main list Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --000000000000a8426005990d40e3 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, Dec 5, 2019 at 7:06 PM Lawrence Stewart wrote= : > At the other end of PPP history, I=E2=80=99ve always felt that the best p= art 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 =E2=80=9Ccommunications register=E2=80=9D that could be wr= itten 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 ther= e > to multiplexing the comm register to provide two serial ports. We used t= he > 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 spit= e > 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. > Seconded... At a past life, we had a SONET circuit that we were using for timing signals, but needed some way to do networking... The timing signals and driver chips we were using precluded using the front door, so we used the 1-byte service field per frame to do PPP, which we did have access to (and was the only data field we had access to). Warner --000000000000a8426005990d40e3 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Thu, Dec 5, 2019 at 7:06 PM Lawren= ce Stewart <stewart@serissa.com> wrote:
At= the other end of PPP history, I=E2=80=99ve 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-co= re MIPS-64 chips connected by a rather nice high speed interconnect.=C2=A0 = The chips were booted over JTAG, which is another story, but in addition th= e chip had a =E2=80=9Ccommunications register=E2=80=9D that could be writte= n 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 co= llected on a front end machine.=C2=A0 However, it was a small step from the= re to multiplexing the comm register to provide two serial ports.=C2=A0 We = used the second one for PPP using a standard driver on the MIPS end and a s= omewhat strange JTAG driver on the coldfire end.=C2=A0 This scheme let us S= SH into the machine nodes when the high speed interconnect needed debugging= .=C2=A0 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 th= is low-speed application.


=
--000000000000a8426005990d40e3--