[Unix-jun72] Early a.out headers
wkt at tuhs.org
Thu May 1 18:23:55 EDT 2008
On Thu, May 01, 2008 at 01:47:33PM -0400, Brad Parker wrote:
> yes, I think 0405 and 0407 a.out's are different.
I managed to scan in the 2nd Edition manuals, and they are available as a PDF
[ That URL is guaranteed to be ephemeral; Al, could you copy it to bitsavers? ]
The skew on some of the pages comes from the photocopy that I have. Apologies.
1st Edition a.out headers were 0405, 12 bytes long. 2nd Edition a.out headers
were 0407, 14 bytes long. In terms of the userland binaries we have from
this era (on the s2 tape at
http://www.tuhs.org/Archive/PDP-11/Distributions/research/1972_stuff/s2-bits.tar.gz), some binaries are 0405 and others are 0407. Here are the 0405 ones:
Here are the 0407 ones:
As you can see, as and as2 are 0407, hence they are V2 binaries, and so
would be likely to output the V2 header.
I haven't read the the OCR'd kernel source fully yet; in the section for
exec(), there must be code to parse an a.out header. Does it only know
about 0405, or 0407, or both?
Hope this helps,
> I believe the V7 headers are 16 bytes and the text section starts at zero.
> (heh, memory management)
> The v1 headers are 12 bytes and the text section starts at 014 (i.e. the
> header is part of the text section and *it* begins at zero, not the code)
> So, if we assemble with the v7 as we need to adjust things a bit.
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