From: paul.winalski@gmail.com (Paul Winalski)
Subject: [TUHS] Control-T (was top)
Date: Tue, 29 May 2018 13:10:15 -0400 [thread overview]
Message-ID: <CABH=_VRNs1dt=6tKBPcpuk84g9bd6jonPqWejn7kB9zO9DtcEA@mail.gmail.com> (raw)
In-Reply-To: <20180529025511.C6E0318C08A@mercury.lcs.mit.edu>
On 5/28/18, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
>
> The thing that killed an OS was the fact that output was programmed I/O, a
> character at a time; using interrupt-driven operation, it took an interrupt
> per character.
>
> The DH11 used DMA for output, and was much easier on the machine.
Yes, I meant output. Thanks for refreshing my hazy memory. I found
the TU58 technical manual online. It turns out that the TU58 did have
a data buffer, but it's only 128 bytes, so transferring each 512-byte
block required multiple messages and interrupts, and that introduces
the overrun/underrun problems.
Most large VAX timesharing systems used the DH11.
-Paul W.
next prev parent reply other threads:[~2018-05-29 17:10 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-29 2:55 Noel Chiappa
2018-05-29 17:10 ` Paul Winalski [this message]
[not found] <mailman.1.1527732002.17884.tuhs@minnie.tuhs.org>
2018-05-31 15:02 ` Johnny Billquist
2018-05-31 21:42 ` Nemo
[not found] <mailman.1.1527559201.18622.tuhs@minnie.tuhs.org>
2018-05-29 22:45 ` Johnny Billquist
2018-05-30 0:19 ` Clem cole
2018-05-30 0:20 ` Clem cole
2018-05-30 22:10 ` Johnny Billquist
2018-05-30 23:14 ` Pete Turnbull
2018-05-30 1:10 ` Dave Horsfall
-- strict thread matches above, loose matches on Subject: below --
2018-05-29 21:21 Norman Wilson
2018-05-30 9:06 ` arnold
2018-05-29 18:49 Noel Chiappa
2018-05-30 1:05 ` Dave Horsfall
2018-05-24 12:20 [TUHS] History of top Noel Chiappa
2018-05-24 14:09 ` Clem Cole
2018-05-24 14:50 ` [TUHS] Control-T (was top) Ronald Natalie
2018-05-24 15:01 ` Clem Cole
2018-05-24 15:48 ` Lars Brinkhoff
2018-05-24 15:08 ` Arthur Krewat
2018-05-28 22:32 ` Paul Winalski
2018-05-28 23:11 ` Clem cole
2018-05-28 23:32 ` Arthur Krewat
2018-05-29 1:12 ` Dave Horsfall
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