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From: George Michaelson <ggm@algebras.org>
To: Larry McVoy <lm@mcvoy.com>
Cc: TUHS main list <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] If not Linux, then what?
Date: Wed, 28 Aug 2019 08:30:01 +1000	[thread overview]
Message-ID: <CAKr6gn2V_T_EnYaz3OYassHSpLecoKTkqZe+By8A9kQQ=7jnMA@mail.gmail.com> (raw)
In-Reply-To: <20190827145556.GD13570@mcvoy.com>

BSD, but with the original STREAMS semantics, not sockets.

DARPA did us no favours accepting sockets in place of simple file I/O
semantics for networks.

Newcastle connection put the namespace into
/.../remote-part/path/to/thing which I felt was also good.

So for me, 7 -> BSD -> got worse for some values of worse

On Wed, Aug 28, 2019 at 12:56 AM Larry McVoy <lm@mcvoy.com> wrote:
>
> On Mon, Aug 26, 2019 at 11:14:45PM -0400, Arthur Krewat wrote:
> > On 8/26/2019 10:45 PM, Larry McVoy wrote:
> > >  Which was that the page cache is
> > >*the*  cache.  There is nothing else.
> > Yeah, I re-read what you wrote a few times after I replied, and realized
> > what you meant ... eventually ;)
>
> I might be making too big of a deal about it.  mmap semantics mattered
> a lot when SMPs first showed up and main memory was small.  It meant
> that you could have multiple CPUs seeing and working on the same chunk
> of data at the same time.
>
> It's very similar to way that IOMMUs are exposed to user space these
> days, enabling virtual machines direct access to the I/O devices.
>
> ZFS breaks that model, the data is all in the ARC and if you mmap
> it they have to bcopy the data out of the ARC, into the page cache
> and now they have a consistency problem, you could modify stuff
> via mmap or write and they have to manage that.
>
> That consistency problem is the main reason that Sun almost completely
> killed the buffer cache (it still was used for inodes and directories
> but that was it).  That consistency problem is a pain in the rear,
> all sorts of race conditions and it tended to bit rot.
>
> Jeff and Bill are smart people so I suspect they got it right but I'm
> still stunned that they took such an architecturally bad approach.
> And even more stunned that the oversight people approved it.  There
> is zero chance that the Sun I worked at would have allowed that.
>
> --lm

  reply	other threads:[~2019-08-27 22:30 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-26 23:13 Arthur Krewat
2019-08-26 23:27 ` Warner Losh
2019-08-26 23:37   ` Larry McVoy
2019-08-26 23:56   ` William Pechter
2019-08-27  0:19     ` Arthur Krewat
2019-08-27  0:30       ` Larry McVoy
2019-08-27  0:58         ` Rob Pike
2019-08-27  1:06           ` Clem Cole
2019-08-27  2:53           ` Larry McVoy
2019-08-27  9:47             ` Rob Pike
2019-08-27  7:47           ` arnold
2019-08-27 16:05           ` [TUHS] Running v10 Angelo Papenhoff
2019-08-27 16:27             ` Henry Bent
2019-08-28  4:22               ` Jason Stevens
2019-08-28  7:34                 ` Angelo Papenhoff
2019-08-28 16:46                   ` Henry Bent
2019-08-27  0:59         ` [TUHS] If not Linux, then what? Arthur Krewat
2019-08-27  1:26           ` Dan Cross
2019-08-27  2:45             ` Larry McVoy
2019-08-27  3:14               ` Arthur Krewat
2019-08-27 14:55                 ` Larry McVoy
2019-08-27 22:30                   ` George Michaelson [this message]
2019-08-27 22:40                     ` Larry McVoy
2019-08-27 22:46                       ` George Michaelson
2019-08-27 22:59                         ` [TUHS] [SPAM] " Larry McVoy
2019-08-27 23:10                           ` [TUHS] " Clem Cole
2019-08-28  0:07                             ` George Michaelson
2019-08-28  3:22                           ` [TUHS] [SPAM] " Rob Pike
2019-08-28  3:25                             ` Rob Pike
2019-08-28  4:05                             ` Larry McVoy
2019-08-28 13:52                               ` Clem Cole
2019-08-28 14:31                                 ` [TUHS] " Larry McVoy
2019-08-28 14:57                                   ` Clem Cole
2019-08-28  6:19                         ` Wesley Parish
2019-08-28  6:30                           ` Peter Jeremy
2019-08-28 11:05                             ` Jason Stevens
2019-08-28 11:11                               ` Arrigo Triulzi
2019-08-28 14:04                               ` Clem Cole
2019-08-28 16:34                                 ` Henry Bent
2019-08-28 17:32                                   ` Larry McVoy
2019-08-28 17:51                                     ` Jon Forrest
2019-08-28 18:56                                     ` Clem Cole
2019-08-28 20:23                                       ` Arrigo Triulzi
2019-08-29  3:24                                       ` Lawrence Stewart
2019-08-29 10:55                                         ` Tony Finch
2019-08-28 13:57                             ` Clem Cole
2019-08-28 12:46                           ` Warner Losh
2019-08-27 23:16                       ` Bakul Shah
2019-08-27 23:33                         ` Larry McVoy
2019-08-28  0:21                           ` Bakul Shah
2019-08-28  1:21                             ` Arthur Krewat
2019-08-28  1:46                               ` Larry McVoy
2019-08-27  0:48   ` Clem Cole
2019-08-27  1:25     ` Gregg Levine
2019-08-27  2:16   ` Theodore Y. Ts'o
2019-08-27  2:39     ` Larry McVoy
2019-08-27  5:54       ` Adam Thornton
2019-08-27  6:05         ` Gregg Levine
2019-08-27  1:17 ` Dan Cross
2019-08-28  3:53 ` Charles H. Sauer
2019-08-28  4:30 ` Jason Stevens
2019-08-28  9:36 ` Angus Robinson
2019-08-28  9:50   ` Michael Kjörling
2019-08-28 10:48     ` arnold
2019-08-28 14:10   ` Earl Baugh
2019-08-28 14:55     ` Clem Cole
2019-08-28 14:22   ` Charles H Sauer
2019-08-28 15:00     ` Steve Nickolas
2019-08-28 15:37       ` Richard Salz
2019-08-28 19:54         ` Peter Jeremy
2019-08-28 20:05           ` Christopher Browne
2019-08-28 20:07 ` Christopher Browne
2019-08-28 20:27   ` Adam Thornton
2019-08-28 20:56     ` William Pechter
2019-08-28 22:24       ` Clem cole
2019-08-28 22:27     ` William Pechter
2019-08-28 22:53       ` Arthur Krewat
2019-08-29 18:40       ` Nemo Nusquam
2019-08-29 19:18         ` Steffen Nurpmeso
2019-08-28 22:28     ` Clem cole
2019-08-28 22:48       ` Adam Thornton
2019-08-28 23:01         ` William Pechter
2019-08-28 23:09           ` Adam Thornton
2019-08-29  6:37           ` Wesley Parish
2019-08-28 23:04       ` Gregg Levine
2019-08-29 11:12     ` Tony Finch
2019-08-28 23:19   ` Theodore Y. Ts'o
2019-08-29 13:31     ` A. P. Garcia
2019-08-29 13:55       ` Arthur Krewat
2019-08-29 15:54         ` Thomas Paulsen
2019-08-29 19:19           ` Steffen Nurpmeso
2019-08-31  1:35             ` Dave Horsfall
2019-08-31 15:14               ` Steffen Nurpmeso
2019-08-31 16:58     ` Christopher Browne
2019-08-31 21:20       ` Theodore Y. Ts'o
2019-08-28 21:02 ` Thomas Paulsen

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