7 Jan
2015
7 Jan
'15
2:29 p.m.
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(a)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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