[pups] Re: PDP11 - RQDX1 standalone format utility? --> XXDP

[j.r.engdahl@adelphia.net (Jonathan Engdahl)]

The DSD-4140 (Data Systems Design) is an RX-02 compatible floppy controller.
I had a couple, but they're gone. You can find them on the web here and
there. I have the manual for it as a directory of .jpg files. I had one that
was malfunctioning. It was sort of fun diagnosing it. I found a bad bus
buffer and fixed it.

I think it's an 18-bit DMA board. Might not work with the 11/53. Wait,
though, I have a disk with a special RT-11 driver for it. It puts the DMA
buffers in the first 256K, then copies the data if the final destination is
higher. I'm not sure if BSD can deal with this issue. I've never had to
worry about it. I have all the diags for the 4140 also.

DSD was bought by Qualogy, so some of their stuff has that name on it.

Arclight (www.arcind.net) shows three in stock. The board number is
804140-1.

Second picture down on this page:
http://users.safeaccess.com/engdahl/spare_parts.htm

Here's how it boots:
http://www.classiccmp.org/mail-archive/classiccmp/2001-06/0032.html

--
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: "Gregg C Levine" <hansolofalcon@worldnet.att.net>
To: "'Jonathan Engdahl'" <j.r.engdahl at adelphia.net>; <pups at minnie.tuhs.org>
Sent: Monday, February 24, 2003 12:40 AM
Subject: RE: [pups] Re: PDP11 - RQDX1 standalone format utility? --> XXDP


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
------------------------------------------------------------
"The Force will be with you...Always." Obi-Wan Kenobi
"Use the Force, Luke." Obi-Wan Kenobi
(This company dedicates this E-Mail to General Obi-Wan Kenobi )
(This company dedicates this E-Mail to Master Yoda )



> -----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
> >
> >
> >
> >
> >
> > _______________________________________________
> > PUPS mailing list
> > PUPS at minnie.tuhs.org
> > http://minnie.tuhs.org/mailman/listinfo/pups
>
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