[TUHS] pdp11 UNIX memory allocation.

[Jacob Ritorto]

>
> 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)
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