Hello again from Gregg C Levine
I've got a PDP-11/53 on order, call it. Would that board work there?
And where could I find one of these, RX02 (DSD 4140) board(s)? Also,
what exactly is this RX02 (DSD 4140) board? Its one that I don't quite
remember hearing about.
-------------------
Gregg C Levine hansolofalcon at worldnet.att.net
------------------------------------------------------------
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> -----Original Message-----
> From: pups-admin at minnie.tuhs.org [mailto:pups-admin at minnie.tuhs.org]
On
> Behalf Of Jonathan Engdahl
> Sent: Sunday, February 23, 2003 11:33 PM
> To: cctech at classiccmp.org; pups at minnie.tuhs.org
> Subject: Re: [pups] Re: PDP11 - RQDX1 standalone format utility? -->
XXDP
> 
> Now that I think of it,
> 
> > 000137
> > 145702
> 
> is wrong too. Assuming that the program is relocatable (which in
this case
> it probably is not), and you simply loaded the entire file into
memory, it
> would be offset by the 16 byte header, so you would want to jump to
145722.
> 
> I think I will remove that patch at 20 altogether.
> 
> Did you know that the output from PDPXASM can be loaded to a barely
> twitching PDP-11 via VTserver? I used PDPXASM to write scope loops
for an
> RX02 (DSD 4140) board I resurrected.
> 
> --
> Jonathan Engdahl
> http://users.safeaccess.com/engdahl
> 
> "The things which are seen are temporary,
>  but the things which are not seen are eternal."  II Cor. 4:18
> 
> 
> ----- Original Message -----
> From: "Michael Davidson" <michael_davidson at pacbell.net>
> To: "Jonathan Engdahl" <j.r.engdahl at adelphia.net>
> Cc: <cctech at classiccmp.org>; <pups at minnie.tuhs.org>
> Sent: Sunday, February 23, 2003 4:40 PM
> Subject: Re: [pups] Re: PDP11 - RQDX1 standalone format utility? -->
XXDP
> 
> 
> > Jonathan Engdahl wrote:
> >
> > >I documented the procedure to extract a program from XXDP and put
a
> header
> > >on it so that you can boot it from VTserver or a UNIX disk. It
has been a
> > >long time since I did this to ZRQCH0, so I practiced on the
program that
> I
> > >think Christos needs (ZRQBC1) and sent it to him.
> > >
> > >There's a lot I don't know about the a.out header, so if someone
can
> improve
> > >my method, let me know.
> > >
> > >http://users.safeaccess.com/engdahl/xxdp.htm#hackXXDP
> > >
> > There isn't very much to know about the a.out header,
> > and what you are doing looks OK although I would probably
> > have set a_text to 160000 and left a_data and a_bss as 0.
> >
> > While I am not really familiar with the BSD boot code that
> > vtserver uses when loading a program I am almost certain that
> > it will use the entrypoint address in the a.out header and
> > not just jump to address 0. (remember it's an actual program
> > loader that understands a.out format, not just something that
> > only knows how to load a boot block and jump to it)
> >
> > This is confirmed by the fact that the code you are patching
> > into the image at address 0 is wrong if you want it to get
> > you to the restart address.
> >
> > In your example you have:
> >
> > 000020/ 000167
> > 000022/ 145702
> >
> > If this was loaded at address 0 in memory and the boot code
> > jumped to address 0, you would end up at 145706 *not* 145702
> > (of course, you might very well get lucky and still land on
> > an instruction boundary, but you would have skipped the first
> > 2 words of the restart code).
> >
> > If this code were really necessary (and I'm 99.99% sure that
> > it isn't) you would want either:
> >
> > 000137
> > 145702
> >
> > or:
> >
> > 000167
> > 145676
> >
> >
> >
> >
> >
> > _______________________________________________
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> > PUPS at minnie.tuhs.org
> > http://minnie.tuhs.org/mailman/listinfo/pups
> 
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