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From: jacob.ritorto@gmail.com (Jacob Ritorto)
Subject: [TUHS] pdp11 UNIX memory allocation.
Date: Wed, 7 Jan 2015 08:29:11 -0500	[thread overview]
Message-ID: <CAHYQbfDEy1_BJGT9h6fYwUpgou4gAmiPRb112F1PYwvE28qRjQ@mail.gmail.com> (raw)
In-Reply-To: <alpine.BSF.2.11.1501071722340.58880@aneurin.horsfall.org>

>
> 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...
>
>
Ooh, can we see annotated examples?  This is the really delicious stuff!


>
> I heard a story that on sufficiently-early Unices, the header was indeed
> loaded, hence the "407".
> Any grey-beards here like to comment?
>

+1 for hearing that and wanting to see annotated examples of it as well!

On Wed, Jan 7, 2015 at 1:29 AM, Dave Horsfall <dave at horsfall.org> wrote:

> 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)
> _______________________________________________
> TUHS mailing list
> TUHS at minnie.tuhs.org
> https://minnie.tuhs.org/mailman/listinfo/tuhs
>
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  parent reply	other threads:[~2015-01-07 13:29 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
2015-01-07  6:39             ` Warren Toomey
2015-01-07 10:06               ` Brantley Coile
2015-01-07 13:29             ` Jacob Ritorto [this message]
     [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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