From: jnc@mercury.lcs.mit.edu (Noel Chiappa)
Subject: [TUHS] Unix with TCP/IP for small PDP-11s
Date: Mon, 22 May 2017 21:33:41 -0400 (EDT) [thread overview]
Message-ID: <20170523013341.CAA4118C095@mercury.lcs.mit.edu> (raw)
> From: Clem Cole
> So some other mechanism (also discussed here) needed to be created to
> avoid blocking in the application.
> ...
> Rand, UNET & Chaos had something else that gave the save async function,
> who's name I've forgotten at the moment
I don't think the RAND code had the non-blocking stuff; AFAICR, all it had was
named pipes (effectively). Jack Haverty at BBN defined and implemented two new
calls (IIRC, 'capac()' and 'await()') to do non-blocking I/O. The
documentation for that is in the 'BBN' branch at TUHS:
http://minnie.tuhs.org/cgi-bin/utree.pl?file=BBN-V6/doc/ipc/await
http://minnie.tuhs.org/cgi-bin/utree.pl?file=BBN-V6/doc/ipc/ipc
My memory might be incorrect, but I don't think it was asynchronous (i.e. a
process issued a read() or write(), and that returned right away, before the
I/O was actually done, and the system notified the process later when the I/O
actually completed).
I actually did implement asyn I/O for an early LAN device driver - and just to
make it fun, the device was a DMA device, and we didn't want the overhead of a
copy, so the DMA was direct to buffers in the process - i.e. 'raw' I/O. So
that required some major system tweaks, to keep the process from being swapped
out - or moved around - while the I/O was pending.
> I believe Noel posted the code for same in the last year from one of the
> MIT kernels
I found it on the dump of an MIT machine, but it was never run on any machine
at MIT - we just had the source in case we had any use fot it.
Noel
next reply other threads:[~2017-05-23 1:33 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-23 1:33 Noel Chiappa [this message]
-- strict thread matches above, loose matches on Subject: below --
2017-05-24 15:21 Noel Chiappa
2017-05-24 17:19 ` Jeremy C. Reed
[not found] <mailman.1.1495591202.25149.tuhs@minnie.tuhs.org>
2017-05-24 9:20 ` Paul Ruizendaal
2017-05-23 13:43 Noel Chiappa
2017-05-23 11:35 Paul Ruizendaal
2017-05-23 1:14 Noel Chiappa
2017-05-22 9:28 Paul Ruizendaal
2017-05-22 14:09 ` Clem Cole
2017-05-22 14:51 ` Steve Simon
2017-05-22 16:29 ` Clem Cole
2017-05-22 16:35 ` Ron Natalie
2017-05-22 22:07 ` Paul Ruizendaal
2017-05-22 23:25 ` Clem Cole
2017-05-23 0:36 ` Paul Ruizendaal
[not found] <mailman.1.1495245601.20449.tuhs@minnie.tuhs.org>
2017-05-20 10:46 ` Johnny Billquist
2017-05-20 17:39 ` Henry Bent
2017-05-20 20:40 ` Johnny Billquist
2017-05-20 20:44 ` Henry Bent
2017-05-20 18:18 ` Warner Losh
2017-05-20 19:05 ` arnold
2017-05-20 20:29 ` Warner Losh
2017-05-20 21:41 ` David Arnold
2017-05-20 21:59 ` Erik E. Fair
2017-05-20 20:40 ` Johnny Billquist
2017-05-20 21:05 ` Warner Losh
2017-05-20 21:34 ` Johnny Billquist
2017-05-21 5:13 ` Random832
2017-05-21 11:04 ` Ron Natalie
2017-05-19 15:15 Noel Chiappa
2017-05-19 16:29 ` Henry Bent
2017-05-19 19:04 ` Ron Natalie
2017-05-20 0:15 ` Warner Losh
2017-05-20 0:21 ` Warner Losh
2017-05-19 17:39 ` Clem Cole
2017-05-21 16:16 ` Dave Horsfall
2017-05-21 19:58 ` Clem Cole
2017-05-21 20:57 ` Ron Natalie
2017-05-21 21:26 ` Clem Cole
2017-05-21 21:46 ` William Pechter
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