mac attack

[muta...@gmail.com]

Today I made an attempt to run PDOS on an old Macbook
Pro that my wife has lying around. The computer is second
hand and 10 years old or something, so I assumed it would
still support legacy boot (Dell only seem to have stopped
supporting it in the last couple of years). It runs MacOS 10
currently.

I know nothing about the Mac so started doing a crash
course.

I was surprised that the USB stick was not recognized
when holding down the option key as a google search
suggested. I searched for how to fix that problem, and
found a potential solution, and tried that, holding down
even more keys, in a more bizarre sequence, but still no
luck.

I then went to confirm that the Mac actually supported
legacy boot, and didn't get a straight answer on that,
and then I had the idea to search to confirm that the
Mac actually had a BIOS. No, it does not have a BIOS!

So that completely rules out the USB option.

I then went to install Bochs and went back to 2004
to find some Mac executables.

I finally got to a command prompt, confirmed the
rumors that it was Unix (FreeBSD), confirmed that
it had unzip, a life-saver, and hunted around a bit,
got the Bochs executables in place, ran bximage,
and I was told:

the powerpc architecture is no longer supported

Wow. I wasn't expecting it to be a 64-bit system at
all, as well as invalidating 32-bit executables. Then
I realized - Power PC is a different CPU entirely, and
the Mac has switched to Intel.

I think this is my first encounter with anything
Power PC related, even if it's just a non-working
executable.

So now I need to figure out how to build an x86
version of Bochs that works on x86 MacOS.

BFN. Paul.

[muta...@gmail.com]

I had a brainwave - Unix always comes with a "cc".

But no, "cc" was "command not found".

"gcc" was "command not found" too.

A C compiler would have been the other lifeline
I needed.

BFN. Paul.

[muta...@gmail.com]

I wonder - is it possible to produce 32-bit command-line
executables that work under both "normal" FreeBSD and
also MacOS?

That would be a cool target.

BFN. Paul.

[muta...@gmail.com]

On Monday, May 10, 2021 at 10:10:19 PM UTC+10, muta...@gmail.com wrote:

> I wonder - is it possible to produce 32-bit command-line
> executables that work under both "normal" FreeBSD and
> also MacOS?

It occurs to me that although my custom GCC 3.2.3
was written sometime around 2004 I think, I think
prior to Apple switching to x86, so there won't be a
Mac target, there would hopefully be a FreeBSD target,
and using my existing software as a base, ie GCC 3.2.3,
binutils 2.14a and PDPCLIB, I can probably crank out
FreeBSD executables, and thus hopefully Mac executables.

And yep, I just checked - there is a freebsd and a
freebsd-aout. That latter is particularly appealing
because I have already built binutils to produce
a.out executables.

I just checked the other one, and it is ELF.

BFN. Paul.

[James Harris]

On 10/05/2021 13:10, muta...@gmail.com wrote:
> I wonder - is it possible to produce 32-bit command-line
> executables that work under both "normal" FreeBSD and
> also MacOS?

If you want two or more OS interfaces then there's nothing to stop you
writing them and running programs under them.

But you were talking of different CPUs. For those, a HLL like C should
be ideal as you can write the code of a program once and, if you've
written it to be portable, compile it for the different processors.


--
James Harris

[anti...@math.uni.wroc.pl]

Mac OS has a funky executable and object file format.
Critial piece of code is assembler and linker. Unfortuntely,
they change rather frequently and you need to match them
to Mac OS version. For current Mac OS you can download
them from Apple (as a part of rather large developement
package). I am not sure if you can get them for older
versions of Mac OS, you should ask for advice in Mac OS
groups.

--
Waldek Hebisch