From: pnr@planet.nl (Paul Ruizendaal)
Subject: [TUHS] Another odd comment in V6
Date: Tue, 14 Feb 2017 13:27:48 +0100 [thread overview]
Message-ID: <0B8503D7-D696-4BB6-A2C7-75A95B603036@planet.nl> (raw)
In-Reply-To: <CAH1jEzZsHqxEJpiMizkg6-cLDaaEhzjb9vzicrK0AJaRQT8muQ@mail.gmail.com>
Hi Nick,
Many thanks for that background!
I think the quote from the Gabriel paper indeed refers to software
interrupts, i.e. signals -- it would not make sense otherwise. The
ITS system that the MIT guy referred to is 'large', it ran on PDP10
mainframes.
I understand how executing a signal handler is piggy-backed on the
return from kernel mode. However, when the signal handler is
finished it could either continue with the next instruction or
re-excute the system call trap instruction. See
http://minnie.tuhs.org/cgi-bin/utree.pl?file=2.9BSD/usr/src/sys/sys/trap.c
(towards end) for details how this is actually done in 2.9BSD.
I think you referred to that mechanism as well.
However, my question remains: why is that mysterious comment there,
above ttread() in V6, and is there a link with the Gabriel story?
Paul
On 14 Feb 2017, at 12:27 , Nick Downing wrote:
> Well I don't know about this actual conversation in history so I can't
> help with that. But I can describe how interrupted system calls work.
> [..more..]
next prev parent reply other threads:[~2017-02-14 12:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-14 8:46 Paul Ruizendaal
2017-02-14 11:27 ` Nick Downing
2017-02-14 12:27 ` Paul Ruizendaal [this message]
2017-02-14 12:46 ` Nick Downing
2017-02-14 14:03 ` Lars Brinkhoff
2017-02-14 14:18 ` Nick Downing
2017-02-14 15:50 ` Random832
2017-02-14 14:14 Noel Chiappa
2017-02-14 14:35 ` Paul Ruizendaal
2017-02-14 15:48 ` Random832
2017-02-14 16:06 ` Dan Cross
2017-02-14 15:40 Noel Chiappa
2017-02-14 16:17 Noel Chiappa
2017-02-21 19:23 Norman Wilson
2017-02-22 9:59 ` Tony Finch
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