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From: Larry McVoy <lm@mcvoy.com>
To: Will Senn <will.senn@gmail.com>
Cc: TUHS main list <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] Macs and future unix derivatives
Date: Mon, 8 Feb 2021 10:21:23 -0800	[thread overview]
Message-ID: <20210208182123.GI13701@mcvoy.com> (raw)
In-Reply-To: <f5977ed8-b5ac-b626-a5cf-ec18b1778f91@gmail.com>

On Mon, Feb 08, 2021 at 12:11:08PM -0600, Will Senn wrote:
> And a bonus question, why, oh why, can't we have a contained kernel that
> provides minimal functionality (dare I say microkernel), that is securable,
> and layers above it that other stuff (everything else) can run on with
> auditing and suchlike for traceability?

I can answer the microkernel question I think.  It's discipline.
The only microkernel I ever liked was QNX and I liked it because it was
a MICROkernel.  The entire kernel easily fit in a 4K instruction cache.

The only way that worked was discipline.  There were 3 guys who could
touch the kernel, one of them, Dan Hildebrandt, was sort of a friend
of mine, we could, and did, have conversations about the benefits of a
monokernel vs a microkernel.  He agreed with me that QNX only worked
because those 3 guys were really careful about what went into the
kernel.  There was none of this "Oh, I measured performance and it is
only 1.5% slower now" nonsense, that's death by a hundred paper cuts.
Instead, every change came with before and after cache miss counts
under a benchmark.  Stuff that increased the cache misses was heavily
frowned upon.

Most teams don't have that sort of discipline.  They say they do,
they think they do, but when marketing says we have to do $WHATEVER,
it goes in.

  reply	other threads:[~2021-02-08 18:21 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-08 18:11 Will Senn
2021-02-08 18:21 ` Larry McVoy [this message]
2021-02-08 18:32   ` Justin Coffey
2021-02-08 18:39     ` Larry McVoy
2021-02-09  1:59     ` Theodore Ts'o
2021-02-12 13:48     ` Angel M Alganza
2021-02-08 18:42 ` Henry Bent
2021-02-09  6:55   ` John Gilmore
2021-02-09  7:05     ` Michael Huff
2021-02-16 22:55       ` Greg A. Woods
2021-02-09  7:17     ` Will Senn
2021-02-09 19:02     ` Theodore Ts'o
2021-02-10  1:34       ` Larry McVoy
2021-02-09 22:59     ` Wesley Parish
2021-02-08 18:43 ` Dan Stromberg
2021-02-12 13:39   ` Angel M Alganza
2021-02-08 18:45 ` Thomas Paulsen
2021-02-25 22:45   ` Dave Horsfall
2021-02-08 20:07 ` Al Kossow
2021-02-09  5:10 ` Andrew Warkentin
2021-02-09  7:42   ` [TUHS] QNX John Gilmore
2021-02-09 11:03     ` Robert Brockway
2021-02-09 18:24       ` Nemo Nusquam
2021-02-09 20:18         ` Jose R Valverde via TUHS
2021-02-09 14:05     ` Larry McVoy
2021-02-09  3:58 [TUHS] Macs and future unix derivatives M Douglas McIlroy
2021-02-09  4:07 ` Adam Thornton
2021-02-09  4:13 ` Will Senn
2021-02-09  5:21 ` Andrew Warkentin
2021-02-09  5:29 ` Theodore Ts'o
2021-02-09  6:37   ` Andrew Warkentin
2021-02-09 16:13     ` Theodore Ts'o
2021-02-09 17:31       ` John Cowan
2021-02-09 19:06         ` Chet Ramey
2021-02-10  2:31       ` Andrew Warkentin
2021-02-09 19:00   ` Jon Steinhart
2021-02-10  1:41     ` Larry McVoy
2021-02-10  1:52       ` George Michaelson
2021-02-10  2:24         ` Larry McVoy
2021-02-10  2:44           ` Dan Cross
2021-02-10  3:10             ` Larry McVoy
2021-02-10 20:03             ` Kevin Bowling
2021-02-10  2:57         ` Warner Losh
2021-02-10  2:56       ` Warner Losh
2021-02-10  3:02         ` Larry McVoy
2021-02-10  3:53       ` Andrew Warkentin
2021-02-09 11:34 ` Thomas Paulsen
2021-02-09 18:29 ` Nemo Nusquam
2021-02-09  8:30 Bakul Shah
2021-02-09 12:22 M Douglas McIlroy

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