From: Bakul Shah <bakul@iitbombay.org>
To: Larry McVoy <lm@mcvoy.com>
Cc: Paul Ruizendaal <pnr@planet.nl>,
The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: [TUHS] Re: DG UNIX History
Date: Tue, 15 Nov 2022 07:48:23 -0800 [thread overview]
Message-ID: <D7F9B8CC-16FD-47C1-95B6-1D66B9B2B0ED@iitbombay.org> (raw)
In-Reply-To: <20221115151133.GL16293@mcvoy.com>
On Nov 15, 2022, at 7:11 AM, Larry McVoy <lm@mcvoy.com> wrote:
>
> On Tue, Nov 15, 2022 at 01:03:05AM -0500, Theodore Ts'o wrote:
>> P.S. I remember back in the day when I was engaging in a friendly
>> competition with a FreeBSD hacker on improving the serial driver for
>> the 8250 chip (with no FIFO's!), and I shared with him my idea of
>> using a pair of ring buffers that would get flipped back and forth
>> between the interrupt handler and the tty "bottom-half" (read:
>> software interrupt) handler, and I was told that clists were handed
>> down from Olympus by the AT&T/Unix Gods and he could never get that
>> kind of change into the FreeBSD tty layer. Of course, I was free to
>> make all of the radical changes to Linux's tty layer --- and I did,
>> all in the name of the number of 115kbaud connections that could be
>> handled on a single 40 MHz 386 processor...
>
> I remember being pleasantly surprised that Linus/Linux was open to
> that sort of change. I get why the traditional Unix shops resisted
> be wacks like that but they went too far and it prevented good work.
>
> Linux seemed far more willing to realize that they had it wrong and
> there was a better way. That was refreshing.
>
> Of course they got beat up for it with "Linux is stable/compatible".
At Fortune Systems Dave Yost was able to achieve full-duplex 9600
baud speed on up to 5 ports in V7 Unix without changing the clist
design. This on a 5.6Mhz machine (with 4 cycle memory). The trick
was to specialize interrupt handlers for each port.
next prev parent reply other threads:[~2022-11-15 15:49 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-14 22:11 Paul Ruizendaal
2022-11-14 22:31 ` Clem Cole
2022-11-14 23:54 ` Warner Losh
2022-11-15 6:03 ` Theodore Ts'o
2022-11-15 15:11 ` Larry McVoy
2022-11-15 15:48 ` Bakul Shah [this message]
2022-11-15 17:47 ` Warner Losh
2022-11-15 1:21 ` Stuff Received
-- strict thread matches above, loose matches on Subject: below --
2022-11-14 11:44 arnold
2022-11-12 15:54 [TUHS] " Clem Cole
2022-11-12 16:09 ` [TUHS] " Larry McVoy
2022-11-12 16:52 ` arnold
2022-11-12 17:05 ` Larry McVoy
2022-11-12 17:09 ` Miod Vallat
2022-11-12 17:12 ` Warner Losh
2022-11-12 17:39 ` arnold
2022-11-12 17:13 ` David Barto
2022-11-12 17:37 ` Brad Spencer
2022-11-12 18:04 ` Clem Cole
2022-11-12 18:36 ` Larry McVoy
2022-11-12 19:36 ` Clem Cole
2022-11-13 1:56 ` Larry McVoy
2022-11-12 19:16 ` Dave Horsfall
2022-11-12 19:31 ` Clem Cole
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=D7F9B8CC-16FD-47C1-95B6-1D66B9B2B0ED@iitbombay.org \
--to=bakul@iitbombay.org \
--cc=lm@mcvoy.com \
--cc=pnr@planet.nl \
--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).