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Can RT-11 be loaded into memory using PDP11GUI?

GreyHairedDECfan

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I've been experimenting with PDP11GUI on my PDP-11/73 and know how to load file images into memory.

Is RT-11 tiny enough that I could load it into the memory of the 11/73, and then start it up? Or am I completely off-base with this thinking?
 

tradde

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How much/little memory are we talking? As far as I know RT-11 is one of the smallest of DEC OS's that can run on just about anything with minimal memory. And there are various versions of it too for different purposes.
 

tradde

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Oh, yeah. That is much more than RT-11 requires. I think there are versions that can run in 28k words. I have never run it. I was thinking of installing it just to see how it works. My Professional-350 runs a version of RT-11 but it's not the normal version. I have run BSD 2.11 on my 11/84 and also RSTS v10.
 

AK6DN

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I don't know a version of RT-11 that won't work without some type of attached filesystem device, at minimal an RX floppy drive or even a TU58 drive (or emulator). It is not a fully memory resident system.

That being said, back in the day when I worked at DEC I had a very compute intensive application that ran using RT-11 as the operating system. So I ran it after hours on an 11/70 with 4MB of core (yes core) using a driver called VM: that turned extended memory into a virtual drive. So I would boot from an RK05, init the VM: device, copy the RK05 image to VM:, and then set VM: as the system drive and could then eject the RK05 and run a pure memory resident system. It was VERY fast.

But I don't think PDP11GUI is capable of doing this by itself, it still needs to emulate some type of filesystem device.
 

wa2flq

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I don't know a version of RT-11 that won't work without some type of attached filesystem device, at minimal an RX floppy drive or even a TU58 drive (or emulator). It is not a fully memory resident system.

That being said, back in the day when I worked at DEC I had a very compute intensive application that ran using RT-11 as the operating system. So I ran it after hours on an 11/70 with 4MB of core (yes core) using a driver called VM: that turned extended memory into a virtual drive. So I would boot from an RK05, init the VM: device, copy the RK05 image to VM:, and then set VM: as the system drive and could then eject the RK05 and run a pure memory resident system. It was VERY fast.

But I don't think PDP11GUI is capable of doing this by itself, it still needs to emulate some type of filesystem device.
You could probably do it from a snapshot of an idle image of RT11SJ booted from and including the entire VM with all the necessary bits included. Copy it to a machine. That version of RT-11 would reset then turn on interrupts for devices on a control-c. Jumping to one of the error traps may accomplish the same thing. Slow load and speedly as mentioned, if you could do all your work in 4MB.

Jerry
 

cbscpe

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I think it is much easier to boot RT11 via a second SLU (DLV11 or compatible) and using a TU58 Emulator so I would suggest you get a second SLU.
 

PG31

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AK6DN's comment above about a virtual device reminds me of a configuration that I used to support on 11/70's. The customer had a 4MB Dataram BC202 attached at the end of the Unibus as a "fast disk" called DF0: in RSX11M. I think it emulated a DEC RF-11. Comparable now to an SSD cache tier in a modern storage array:unsure:
 

daver2

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Unfortunately (in another thread) the OP doesn't have any spare DLV11 equivalent serial ports (other than the console).

All of the DEC "standard" operating systems that I know of require some form of disk drive to be present (although - as Don has already pointed out - unused high memory can be used as a virtual disk under certain circumstances). Unfortunately, this has to be initially loaded. This would be painfully slow over the console serial port via PDP11GUI...

EDIT: Unless you had core store or battery backed RAM on your PDP11 of course...

You either require a disk drive (or some form of disk emulation) or a second DLV11-type serial port (to run the TU58 emulator).

At work we have our own Operating Systems and Languages for the DEC PDP-11. These can be loaded from ROM (MRV11-C or MRV11-D cards) or booted over an ETHERNET card from a host machine (another PDP-11 - although I developed a version of our server running on a DOS PC that can boot them). I am trying to persuade my Company to release these Operating Systems and Languages for hobbyist use. But that is taking a while...

Dave
 
Last edited:

Hunta

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You either require a disk drive (or some form of disk emulation) or a second DLV11-type serial port (to run the TU58 emulator).
Or a disk emulator running over a terminal connection. For example:
Code:
PDP-11/23 (2044KW) (PDP-2011 based) FullODT for halt mode (in development :))

>>>B HX5
HX 2.2  RT-11 Cold boot..

HX DSK/TTY multiplexer   v3.3  2016

RT-11SB (S) V05.07

.R MSCPCK

.
 

Hunta

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Another example of loading
Code:
PDP-11/23 (2044KW) (PDP-2011 based) FullODT for halt mode (in development :))

>>>165020G
000027 000000 000000 000000
@
@L 10000
@D 12706
@D 10000
@D 12746
@D 340
@D 12746
@D 10016
@D 2
@D 4567
@D 32
@D 176401
@D 41411
@D 122
@D 0
@D 0
@D 1000
@D 227
@D 105737
@D 177560
@D 100375
@D 113703
@D 177562
@D 207
@D 12704
@D 16
@D 105737
@D 177564
@D 100375
@D 112537
@D 177566
@D 5304
@D 1371
@D 12700
@D 5
@D 4715
@D 5300
@D 1375
@D 12700
@D 1000
@D 4715
@D 110324
@D 5300
@D 1374
@D 4715
@D 4715
@D 5007
@L 10000
@S
HX 2.2  XXDP  Cold boot..



BOOTING UP XXDP-XM EXTENDED MONITOR


XXDP-XM EXTENDED MONITOR - XXDP V2.5
REVISION: F0
BOOTED FROM HX0
124KW OF MEMORY
UNIBUS SYSTEM

RESTART ADDRESS: 152000
TYPE "H" FOR HELP !

.
 

DDS

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To refresh my memory, I went back to your original thread, as suggested by Daver2, and saw that you have a (possibly) working RQDX3 board. I'm not about to tell you which puzzles are more interesting than another, or how you should be spending your spare time. But if I were in your position I would be looking at this:


or perhaps this:


There should be enough info there to let you test your RQDX3 with a readily available 3.5" 1.44m or 5.25" 1.2m floppy drive. If it turns out that your RQDX3 is toast, replacements can be had for not a whole lot of money. In any event, with a bit of tinkering you should be able to put something together that would let you boot RT11 or XXDP off of a floppy disk and debug whatever is not quite right with your 11/73. There's a pretty good walk through at those links on the hardware, software, and equipment needed to pull it off. You likely already have the DEC equivalent board needed to interface a floppy with your RQDX3. Getting something workable might be as simple as preparing a disk, hooking up a floppy drive, and booting up.

Be advised that the originator of the site linked to above is a frequent flyer on this site.
 

GreyHairedDECfan

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To refresh my memory, I went back to your original thread, as suggested by Daver2, and saw that you have a (possibly) working RQDX3 board. I'm not about to tell you which puzzles are more interesting than another, or how you should be spending your spare time. But if I were in your position I would be looking at this:


or perhaps this:


There should be enough info there to let you test your RQDX3 with a readily available 3.5" 1.44m or 5.25" 1.2m floppy drive. If it turns out that your RQDX3 is toast, replacements can be had for not a whole lot of money. In any event, with a bit of tinkering you should be able to put something together that would let you boot RT11 or XXDP off of a floppy disk and debug whatever is not quite right with your 11/73. There's a pretty good walk through at those links on the hardware, software, and equipment needed to pull it off. You likely already have the DEC equivalent board needed to interface a floppy with your RQDX3. Getting something workable might be as simple as preparing a disk, hooking up a floppy drive, and booting up.

Be advised that the originator of the site linked to above is a frequent flyer on this site.
Interesting concept. I have a 2nd DLV11 on its way, so my plan is to use TU58FS to run xxdp to determine exactly what is working and what is not. Thanks for this option though.
 

Hunta

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Is that a bespoke boot ROM?

Is there anything on the web related to this?

Loading via the console is built into the VT-52 terminal emulation program on the PC side. Loading via FullODT in PDP-2011 was added by me. Physical computers, of course, do not support booting directly from HX, but, at least for KDJ11-B, I can add a bootloader into ROM. On processor boards I know, booting through a terminal emulation program is worked.

There is a website, but it is in Russian. The author of the concept, drivers and terminal emulation program is also from Russia.

The author's driver for XXDP was slightly modified by me to support a maximum device size of 32MB - so that all XXDP tests can be copied
 
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