[Simh] RT-11 source

Sun Oct 23 12:34:21 EDT 2016

You might think that the Tanenbaum book would be narrowly focused on 
Minix. It isn't -- it covers operating system concepts in general.

I recommend the book more than the OS. Minix is written to be an 
understandable classroom example. It does things that a serious OS 
probably would optimize better. For example a generic hardware interrupt 
handler adds a device specific interrupt handler to the process queue 
that is scheduled as a high priority process by the process scheduler. 
Unibus interrupts on a 780 weren't that bad.

On 10/23/2016 12:23 PM, Dave Wade wrote:
>
> Ray,
>
> I really suggest that you look at the Tanenbaum book. It goes into 
> each component of an operating system and explains the structures that 
> it uses and how the parts fit together. Looking at the code often does 
> not explain this. Even were there are comments the usually don’t 
> explain how things mesh, which is all important.
>
> Dave
>
> *From:*Simh [mailto:simh-bounces at trailing-edge.com] *On Behalf Of *Ray 
> Jewhurst
> *Sent:* 23 October 2016 03:20
> *To:* Johnny Billquist <bqt at softjar.se>
> *Cc:* simh at trailing-edge.com
> *Subject:* Re: [Simh] RT-11 source
>
> 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 
> <mailto: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
>         <mailto: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
>
>         -------------------------------------------------------------------------------
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>     -- 
>     Johnny Billquist                  || "I'm on a bus
>                                       ||  on a psychedelic trip
>     email: bqt at softjar.se <mailto:bqt at softjar.se>            || 
>     Reading murder books
>     pdp is alive!                     ||  tryin' to stay hip" - B. Idol
>
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