From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FROM,HTML_MESSAGE,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 8239 invoked from network); 3 Sep 2021 17:11:43 -0000 Received: from minnie.tuhs.org (45.79.103.53) by inbox.vuxu.org with ESMTPUTF8; 3 Sep 2021 17:11:43 -0000 Received: by minnie.tuhs.org (Postfix, from userid 112) id 541A49C875; Sat, 4 Sep 2021 03:11:41 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 0B5CE9C870; Sat, 4 Sep 2021 03:11:14 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="jjCdL6It"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id 22DE09C870; Sat, 4 Sep 2021 03:11:12 +1000 (AEST) Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) by minnie.tuhs.org (Postfix) with ESMTPS id 11C2A9BA1E for ; Sat, 4 Sep 2021 03:11:10 +1000 (AEST) Received: by mail-pl1-f179.google.com with SMTP id m17so3671077plc.6 for ; Fri, 03 Sep 2021 10:11:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=6fsiS5rOBC/dLDHEU7JvfCVjxLykJ7njGo9PK7NYu04=; b=jjCdL6ItQu86+j54ANAUuCK9F03NKIvCgqUKq+Dsui72kHDCyxlnjzK/33Zn9cAYs6 rPlj6+YB8rRrP7HbtbsaYqhyyG3X4hcC/nPH1gugoT1+IYoq23+kHZ08M8hW2Hagbb4w VC571R6fKhGSaEN2K9txfTqG/m9A7AhaShHmxkpSi/WcgqOF8VCsOWm4lWnuJP+6i1uD mdaEgayhJTO1N5FEJxqYMsEY9KYFLYXV4Tuz0c0I2DqGQQ6Y+3LxJhF+0rGKmY2RpL97 04mmg38WVTI961HXeNohK0fvVimHof1yC7z2hCgoygQStICNpXBA5i7Qn5wM7RqhHsFC +yHg== 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; bh=6fsiS5rOBC/dLDHEU7JvfCVjxLykJ7njGo9PK7NYu04=; b=OLRsRTapUWnb1Dc0kjCS9iNNj052e8L55G/3QP9Tt5dGgL+J4MMJm9l9Aq6fJcIR8s 7obcpSSL5hqnd164M392QOyFXbtuzJy95kHzCE9LgUyTH6eylZE9NiBDSC+owKXafBzZ rQW+7pim7EW/wFBPQtmpS3HCcF7aUC5UknOE/ZTw1EJbcJDsr+7FfgWWGsI+Ivf6zGKe XopUHjp5unDgD3/3gLa4Uoth18x0y9QIJAr3ujhdr1LWqtAL2W3C+KRjNXQRSI5pdWn2 tCa9/EyLVHOni3gDuDpDEfmfF3dOlopAqr/4qVx+2WxGCr/EatML0SGl5aiEUTkY6wI9 17DA== X-Gm-Message-State: AOAM531h6yCXOAlouakILgtl0fZ4w+LqbiY5hqdx/QOHp3eRifJTV40t tZOLzmYBFrTp6zBthM6ve0xVrCCaMRqo+n9W0NDuzvZ/ X-Google-Smtp-Source: ABdhPJzK6u66bLx+/TSf/BdVa+SUr0RRc2auqwD/r6vJjzxZ5h+v8cp58Sf0J5BnYe6rm7XqW8DSa0YlDr0jrbBzBCA= X-Received: by 2002:a17:902:c246:b0:136:c582:ebd with SMTP id 6-20020a170902c24600b00136c5820ebdmr4058021plg.61.1630689069124; Fri, 03 Sep 2021 10:11:09 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Adam Thornton Date: Fri, 3 Sep 2021 10:10:57 -0700 Message-ID: To: Warner Losh , The Eunuchs Hysterical Society Content-Type: multipart/alternative; boundary="000000000000b44e2e05cb1a62d2" Subject: Re: [TUHS] ATC/OSDI'21 joint keynote: It's Time for Operating Systems to Rediscover Hardware (Timothy Roscoe) 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: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --000000000000b44e2e05cb1a62d2 Content-Type: text/plain; charset="UTF-8" Much of the problem, I think, is that: 1) an idealized PDP-11 (I absolutely take Warner's point that that idealization never really existed) is a sufficiently simple model that a Bear Of Little Brain, such as myself, can reason about what's going to happen in response to a particular sequence of instructions, and get fairly proficient in instructing the machine to do so in a non-geological timeframe. 2) a modern CPU? Let alone SoC? Fuggedaboutit unless you're way, way smarter than I am. (I mean, I do realize that this particular venue has a lot of those people in it...but, really, those are people with extraordinary minds.) There are enough people in the world capable of doing 1 and not 2 that we can write software that usually mostly kinda works and often gets stuff done before collapsing in a puddle of nasty-smelling goo. There aren't many people at all capable of 2, and as the complexity of systems increases, that number shrinks. In short, this ends up being the same argument that comes around every so often, "why are you people still pretending that the computer is a PDP-11 when it clearly isn't?" Because, as with the keys and the streetlight, that's what we have available to us. Only a grossly oversimplified model fits into our heads. Adam On Fri, Sep 3, 2021 at 8:57 AM Warner Losh wrote: > > > On Wed, Sep 1, 2021 at 4:00 PM Dan Cross wrote: > >> I'm curious about other peoples' thoughts on the talk and the overall >> topic? >> > > My comment is that the mental map that he presents has always been a lie. > At least it's been a lie from a very early time. > > Even in Unibus/Qbus days, the add-in cards had some kind of processor > on it from an early time. Several of the VAX boards had 68000 or similar > CPUs that managed memory. Even the simpler MFM boards had buffer > memory that needed to be managed before the DMA/PIO pulled it out > of the card. There's always been an element of different address spaces > with different degrees of visibility into those address spaces. > > What has changed is all of these things are now on the SoC die so > you have good visibility (well, as good as the docs) into these things. > The number of different things has increased, and the for cross domain > knowledge has increased. > > The simplistic world view was even inaccurate at the start.... > > Warner > --000000000000b44e2e05cb1a62d2 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Much of the problem, I think, is that:

=
1) an idealized PDP-11=C2=A0 (I absolutely take Warner's poi= nt that that idealization never really existed) is a sufficiently simple mo= del that a Bear Of Little Brain, such as myself, can reason about what'= s going to happen in response to a particular sequence of instructions, and= get fairly proficient in instructing the machine to do so in a non-geologi= cal timeframe.

2) a modern CPU?=C2=A0 Let alone So= C?=C2=A0 Fuggedaboutit unless you're way, way smarter than I am.=C2=A0 = (I mean, I do realize that this particular venue has a lot of those people = in it...but, really, those are people with extraordinary minds.)
<= div>
There are enough people in the world capable of doing 1 = and not 2 that we can write software that usually mostly kinda works and of= ten gets stuff done before collapsing in a puddle of nasty-smelling goo.=C2= =A0 There aren't many people at all capable of 2, and as the complexity= of systems increases, that number shrinks.

In sho= rt, this ends up being the same argument that comes around every so often, = "why are you people still pretending that the computer is a PDP-11 whe= n it clearly isn't?"=C2=A0 Because, as with the keys and the stree= tlight, that's what we have available to us.=C2=A0 Only a grossly overs= implified model fits into our heads.

Adam
<= /div>

On Fri, Sep 3, 2021 at 8:57 AM Warner Losh <imp@bsdimp.com> wrote:


On Wed, Sep = 1, 2021 at 4:00 PM Dan Cross <crossd@gmail.com> wrote:
I'm curious about other p= eoples' thoughts on the talk and the overall topic?

My comment is that the mental map that he presents= has always been a lie.
At least it's been a lie from a very = early time.

Even in Unibus/Qbus days, the add-in c= ards had some kind of processor
on it from an early time. Several= of the VAX boards had 68000 or similar
CPUs that managed memory.= Even the simpler MFM boards had buffer
memory that needed to be = managed before the DMA/PIO pulled it out
of the card. There's= always been an element of different address spaces
with differen= t degrees of visibility into those address spaces.

What has changed is all of these things are now on the SoC die so
you have good visibility (well, as good as the docs) into these things.
The number of different things has increased, and the for cross do= main
knowledge has increased.

The simpli= stic world view was even inaccurate at the start....

Warner=C2=A0
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