From: Dan Cross <crossd@gmail.com>
To: Larry McVoy <lm@mcvoy.com>
Cc: Bakul Shah <bakul@iitbombay.org>,
The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: [TUHS] Re: Clever code (was Re: Re: Stdin Redirect in Cu History/Alternatives?
Date: Thu, 15 Dec 2022 09:18:42 -0500 [thread overview]
Message-ID: <CAEoi9W7F73OL_Mro1PPqdS7H4xTCx6YdsWujrpUn1ytROuQhFg@mail.gmail.com> (raw)
In-Reply-To: <20221215140659.GE21275@mcvoy.com>
On Thu, Dec 15, 2022 at 9:07 AM Larry McVoy <lm@mcvoy.com> wrote:
> On Thu, Dec 15, 2022 at 09:02:08AM -0500, Dan Cross wrote:
> > On Thu, Dec 15, 2022 at 12:38 AM Bakul Shah <bakul@iitbombay.org> wrote:
> > > Don't see how unless they put multiple related services in the same
> > > address space, which reduces context switching but tends toward a
> > > monokernel (& increased coupling). Unless I am misunderstanding you.
> >
> > I don't see why two services in a microkernel couldn't arrange to
> > share a region of memory and implement bidirectional queues
> > between themselves. With an appropriate signalling mechanism,
> > you'd still be context switching but avoiding a lot of copying.
>
> My mind went to similar thoughts. How did QNX manage the page cache?
> Did they have mmap?
I don't know if they did historically, but I kind of doubt it; QNX predates
4.2BSD, and I imagine there wasn't much influence from TENEX/PMAP).
But they seem to now:
https://www.qnx.com/developers/docs/7.1/#com.qnx.doc.neutrino.getting_started/topic/s1_resmgr_io_mmap.html
No idea how they handle page caching. That's an interesting question,
given how they adopted POSIX and try to at least give the outward
appearance of being Unix-y.
Given the emphasis on the message-based architecture, where messages
can be sent between nodes, I doubt there's that much support for shared
memory as a basis for IPC; I think they favored explicit messaging copying
facilitated by the ukernel. Whether you could build something bespoke using
the provided primitives is another matter.
- Dan C.
next prev parent reply other threads:[~2022-12-15 14:20 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-10 19:38 [TUHS] " segaloco via TUHS
2022-12-11 0:22 ` [TUHS] " Clem Cole
2022-12-11 2:37 ` segaloco via TUHS
2022-12-11 13:59 ` Michael Kjörling
2022-12-11 14:28 ` Steve Nickolas
2022-12-11 15:04 ` Dan Cross
2022-12-13 1:54 ` Larry McVoy
2022-12-11 17:18 ` Adam Thornton
2022-12-11 18:54 ` Michael Kjörling
2022-12-11 19:55 ` Dave Horsfall
2022-12-11 20:03 ` Larry McVoy
2022-12-11 23:22 ` segaloco via TUHS
2022-12-12 2:15 ` [TUHS] Clever code (was " Bakul Shah
2022-12-12 2:44 ` [TUHS] " Steve Nickolas
2022-12-12 3:09 ` Andrew Warkentin
2022-12-12 3:34 ` Larry McVoy
2022-12-12 5:00 ` Kevin Bowling
2022-12-12 5:26 ` Andrew Warkentin
2022-12-12 15:02 ` Larry McVoy
2022-12-12 15:29 ` Clem Cole
2022-12-12 15:39 ` Dan Cross
2022-12-12 16:04 ` Larry McVoy
2022-12-12 16:26 ` Clem Cole
2022-12-12 22:20 ` Liam Proven
2022-12-12 23:10 ` segaloco via TUHS
2022-12-12 23:24 ` Larry McVoy
2022-12-13 2:00 ` Andrew Warkentin
2022-12-13 13:37 ` Larry McVoy
2022-12-13 23:00 ` Andrew Warkentin
2022-12-14 1:05 ` Larry McVoy
2022-12-14 1:40 ` segaloco via TUHS
2022-12-14 6:32 ` Rich Morin
2022-12-14 2:01 ` Andrew Warkentin
2022-12-14 7:49 ` arnold
2022-12-14 11:54 ` Brad Spencer
2022-12-14 12:08 ` [TUHS] Re: (TUHS -> COFF?) Re: Clever code Michael Kjörling
2022-12-14 15:14 ` [TUHS] Microware's OS-9 (was: Clever code) G. Branden Robinson
2022-12-14 22:41 ` [TUHS] " John Cowan
2022-12-14 9:46 ` [TUHS] Re: Clever code (was Re: Re: Stdin Redirect in Cu History/Alternatives? Harald Arnesen
2022-12-15 18:33 ` Liam Proven
2022-12-16 10:42 ` Harald Arnesen
2022-12-18 14:05 ` Liam Proven
2022-12-18 15:08 ` Stuff Received
2022-12-19 11:47 ` Liam Proven
2022-12-20 8:30 ` Andrew Warkentin
2022-12-20 11:57 ` Liam Proven
2022-12-15 0:29 ` Bakul Shah
2022-12-15 2:54 ` Larry McVoy
2022-12-15 5:36 ` Bakul Shah
2022-12-15 14:02 ` Dan Cross
2022-12-15 14:06 ` Larry McVoy
2022-12-15 14:18 ` Dan Cross [this message]
2022-12-15 14:02 ` Larry McVoy
2022-12-15 8:01 ` Andrew Warkentin
2022-12-12 9:48 ` [TUHS] Re: Clever code Michael Kjörling
2022-12-12 21:34 ` [TUHS] Re: Stdin Redirect in Cu History/Alternatives? Dave Horsfall
2022-12-12 21:46 ` Chet Ramey
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=CAEoi9W7F73OL_Mro1PPqdS7H4xTCx6YdsWujrpUn1ytROuQhFg@mail.gmail.com \
--to=crossd@gmail.com \
--cc=bakul@iitbombay.org \
--cc=lm@mcvoy.com \
--cc=tuhs@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).