[TUHS] pdp11 UNIX memory allocation.

[Dave Horsfall]

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."
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