From: dave@horsfall.org (Dave Horsfall)
Subject: [TUHS] pdp11 UNIX memory allocation.
Date: Wed, 7 Jan 2015 17:29:45 +1100 (EST) [thread overview]
Message-ID: <alpine.BSF.2.11.1501071722340.58880@aneurin.horsfall.org> (raw)
In-Reply-To: <2509FDBD-67C4-4552-BB58-01281049DCB6@ronnatalie.com>
On Tue, 6 Jan 2015, Ronald Natalie wrote:
> Yep, the only time this [the 407 magic number] was ever trully useful
> was so you could put an a.out directly into the boot block I think.
But why would you include an a.out header in a boot block? When you only
had 512 bytes, every one of 'em counted, and I, oops, I mean others, had
to resort to vile stuff such as self-modifying code...
> During normal operations the a.out header was never actually loaded into
> the user memory.
I heard a story that on sufficiently-early Unices, the header was indeed
loaded, hence the "407".
Any grey-beards here like to comment?
--
Dave Horsfall DTM (VK2KFU) "Bliss is a MacBook with a FreeBSD server."
http://www.horsfall.org/spam.html (and check the home page whilst you're there)
next prev parent reply other threads:[~2015-01-07 6:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.147.1420574271.3354.tuhs@minnie.tuhs.org>
2015-01-06 20:20 ` Johnny Billquist
2015-01-06 20:33 ` random832
2015-01-06 21:57 ` Ronald Natalie
2015-01-06 22:00 ` Clem Cole
2015-01-06 22:04 ` Ronald Natalie
2015-01-07 1:46 ` Dave Horsfall
2015-01-07 2:00 ` Ronald Natalie
2015-01-07 6:29 ` Dave Horsfall [this message]
2015-01-07 6:39 ` Warren Toomey
2015-01-07 10:06 ` Brantley Coile
2015-01-07 13:29 ` Jacob Ritorto
[not found] ` <CAC20D2PP1hGyYsep1yNtj9KO55a-V02+QHS+S7bX-4joJy222g@mail.gmail.com>
[not found] ` <1420583703.863814.210431037.61D6C6EC@webmail.messagingengine.com>
2015-01-06 22:36 ` random832
[not found] <mailman.149.1420581544.3354.tuhs@minnie.tuhs.org>
2015-01-06 22:20 ` Johnny Billquist
2015-01-06 22:36 ` Ronald Natalie
2015-01-06 23:14 ` Johnny Billquist
2015-01-07 2:39 ` John Cowan
2015-01-07 2:59 ` Johnny Billquist
2015-01-06 22:45 Noel Chiappa
2015-01-06 22:55 ` Clem Cole
[not found] <mailman.151.1420584979.3354.tuhs@minnie.tuhs.org>
2015-01-06 23:34 ` Johnny Billquist
2015-01-06 23:52 ` scj
2015-01-07 16:14 ` Clem Cole
2015-01-07 17:27 ` Dave Horsfall
2015-01-07 2:18 Noel Chiappa
2015-01-07 16:17 ` Clem Cole
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