[Simh] RT-11 source

[Ray Jewhurst]

Thank you Johnny. I may ruffle some feathers, but I hate C.  I am mildly
autistic and the way my mind works I actually prefer assembly over high
level languages. I would really like a blueprint to see what I am doing. Is
there commented code for DOS/BATCH? Or even CAPS-11. I would like love to
see a fully commented kernel to see what I am up against.

Thanks
Ray

On Oct 22, 2016 9:11 PM, "Johnny Billquist" <bqt at softjar.se> wrote:

While we're at it then... Ray asked for RT-11, since he felt that it was
smaller and simpler than most other operating systems available, and also
because he felt more comfortable with assembler than some other language.

Both those points are missed with any Unix-like OS, even if the intention
is good.

I could just as well offer up RSX, since it actually comes with source
where the comments are still in place, and it's actually written in
assembler for the most part as well. However, it is a much more complex
system than RT-11, and in some ways probably more complex than Unix as
well. So I don't think it might be a good choice if you just want to
understand how an OS works.

In fact, I would probably suggest Ray start with just writing some code to
do some simple things without looking at existing code. The first thing
needed would be to just have something that can load programs from a
device, and run them. This will require some simple device driver, some
simple file system, and a simple command line interpreter. Then you can go
on an expand from there. You'll soon realize things you want to abstract
away, and deal with in a somewhat coherent way.
I wouldn't bother with interrupt system, MMU, or any more fancy stuff to
start with. A plain 64K PDP-11, with the program loader just located in one
end, and then go from there. Do system calls through TRAP, EMT or some
other instruction, and then have a vector installed. If the user program
overwrites that, tough luck.

        Johnny


On 2016-10-23 02:45, Nelson H. F. Beebe wrote:

> Ray Jewhurst <raywjewhurst at gmail.com> asks today for documented
> operating system source code for the PDP-11.  Besides the Lions' Unix
> v6 code, there is also Doug Comer's Xinu project about which he wrote
> several books.  Current versions are targeted at x86 and ARM CPUs,
>
>         http://www.xinu.cs.purdue.edu/
>
> but he still provides code for older systems (PDP-11, SPARC, VAX):
>
>         ftp://ftp.cs.purdue.edu/pub/comer/
>
> There is more about him here, including links to his books Web site:
>
>         https://en.wikipedia.org/wiki/Douglas_Comer
>
> ------------------------------------------------------------
> -------------------
> - Nelson H. F. Beebe                    Tel: +1 801 581 5254
>     -
> - University of Utah                    FAX: +1 801 581 4148
>     -
> - Department of Mathematics, 110 LCB    Internet e-mail:
> beebe at math.utah.edu  -
> - 155 S 1400 E RM 233                       beebe at acm.org
> beebe at computer.org -
> - Salt Lake City, UT 84112-0090, USA    URL:
> http://www.math.utah.edu/~beebe/ -
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-- 
Johnny Billquist                  || "I'm on a bus
                                  ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol
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