[Simh] RSX-20F

[Johnny Billquist]

On 2015-03-19 23:57, Timothe Litt wrote:
> On 19-Mar-15 18:43, Johnny Billquist wrote:
>>
>> All true. Except I don't think VMS actually do relocation at load
>> time. The VAX instruction set was capable enough that pretty much all
>> code you ever wrote was already PIC. The only things to resolve were
>> external symbols, but I don't think VMS allowed shareable images to
>> refer to external, unresolved symbols to start with. But I might be
>> wrong on that.
>>
> You are.  The image activator dealt with G^ symbol fixups.  One tried to
> avoid them, as they caused imgact to do extra work, and the instructions
> that needed to be fixed-up made their pages non-sharable.  You can write
> PIC code, on VAX, but don't have to.  But that's another diversion, and
> I have other things to do.

So do I. Bringing in VMS was in itself very tangential to the thread, 
which was already very tangential.

>> And yes, -20F looks truly like a weird hybrid, with even the
>> documentation not correct.
>>
> The documentation is correct, as far as it goes.  It's just not
> complete.  Any doc has some errors.  And this was reverse-engineered.
> Be grateful that some of us fought for funding to get the internal notes
> and training materials published.

Well, I still consider that more wrong than incorrect.

>> Probably.  But unless you also have 11D code, don't be too sure.  11M
>>> practiced code reuse before it was popular.  M may have started with D's
>>> BOOT.
>>
>> Nope. The comments in the BOOT sources even says it is 11M.
>>
> That doesn't contradict my point.  Its origin may well have been 11D,
> before 11M adopted it.

You can continue to argue that. That don't make it correct. And then we 
could go on arguing that it all comes from RSX-11C one way or another. 
It is clear that the code in the listing of BOOT.MAC included in the 
Tops-20 files are directly imported from RSX-11M either way.

>>> his was the basis of the 20F drivers.
>>
>> Loadable device drivers have been around for a long, long time in 11M.
>> But, unlike 11D, device drivers in 11M were never tasks.
> I've been around longer.  When I first used 11M, they had to be sysgened
> into the exec.  It was big news when they became (optionally) loadable.
> And somewhat of a pain to upgrade, though avoiding the full exec TKB was
> helpful when developing.

Yes. And now we're talking about RSX-11M V2 or earlier. Which place us 
at or before the KL was released.

>> And the drivers in -20F do appear to be like tasks, and they even
>> define the RSX11D symbol, so they definitely are in the 11D vein.
>>
>
> As I said, keep looking and you'll keep validating what I wrote.  This
> started when I said the drivers came from 11D, and you disbelieved me...

Yes, because that was not what was suggested by the RSX-20F manual...

> As far as I'm concerned, this conversation is over.

I don't know where this hostility comes from. Noone demanded that you 
reply. I'm trying to figure some things out, as it turned out some 
things I believed was proven wrong.

	Johnny