[vcf-midatlantic] LSI-11 simulator

Richard Cini rich.cini at gmail.com
Thu Sep 10 13:32:15 EDT 2020

I've used PDP11GUI for various things, as well as the TU58, so I will give that a try. Thanks.

Rich Cini

On 9/10/20, 1:16 PM, "vcf-midatlantic on behalf of Bill Degnan via vcf-midatlantic" <vcf-midatlantic-bounces at lists.vcfed.org on behalf of vcf-midatlantic at lists.vcfed.org> wrote:

    Sorry I forgot my web page notes:
    Let me know how it goes.
    On Thu, Sep 10, 2020 at 1:13 PM Bill Degnan <billdegnan at gmail.com> wrote:
    > PDP11GUI allows you to create bootable media by simulating tape storage
    > via PC rs232 port.  What I did was use simH to create the boot disk I
    > wanted, tested to make sure it worked and then used PDP11GUI to dump the
    > image onto an awaiting RL02 disk.  You can do the same with RK05 and I
    > presume RX01/2 as well.
    > Bill
    > On Thu, Sep 10, 2020 at 12:25 PM Herb Johnson via vcf-midatlantic <
    > vcf-midatlantic at lists.vcfed.org> wrote:
    >> > No RT-11 disk image I’ve used will boot,
    >> > I was hoping someone could point me to a listing of what the on-disk
    >> boot block code on an RT-11 floppy might look like.
    >> Rich, I don't understand your problem. If you have access to RT-11 disk
    >> images on the Web, my guess is some of them are "bootable". By
    >> "bootable" that means by your account, they have PDP11 boot code on
    >> their first sector. If they have boot code on their first sector - then
    >> extract the first sector and *hand disassemble the binary*. Then you
    >> know what that code quote "looks like".
    >> 256 words (512 bytes) is just a handful of disassembly work - hardly
    >> worth bothering to run an emulator to run some debugger to produce some
    >> PDP-11 code. and you seem so deep into this custom  emulator and the
    >> LSI-11 architecture, that you seem to know what you'd need to make sense
    >> of the boot code. I'm familiar with PDP-11's a little, it's not
    >> horrendous binary code.
    >> YOu also say, this emulator apparently needs a custom RT-11, presumably
    >> with custom boot code. But the creator doesn't recall the details. Well,
    >> 24 years is a long time to remember such things. That being the case,
    >> you will have to figure out the boot process anyway. You already have to
    >> dig into the emulator. And you seem to know the hardware. Thus doing the
    >> hand disassembly will be, er, "informative".
    >> What am I missing here? Do you need some known bootable RT-11 diskettes,
    >> so you can put one in some drive and read off the boot sector? Or
    >> someone to send you that binary or disk image?
    >> Likewise:
    >> >  It’s like looking for a disassembly of the MS-DOS boot sector.
    >> (snort) MS-DOS DEBUG will do that, with a IBM PC tech manual in hand.
    >> I don't mean to belabor the point, but maybe this is as I suspect: a
    >> desire to avoid hand-disassembly. If that's a personal issue, my
    >> apologies, but I think it's a very useful skill. And if it's not a
    >> desirable task, well, there's usually debuggers which do that, or one
    >> can cobble up a disassembler in one's favorite language (or borrow one
    >> and rework it). I've done all those things, and still do, but that's
    >> just me.
    >> Puzzled, Herb
    >> --
    >> Herbert R. Johnson, New Jersey in the USA
    >> http://www.retrotechnology.com OR .net
    >> preserve, recover, restore 1970's computing
    >> email: hjohnson AT retrotechnology DOT com
    >> or try later herbjohnson AT retrotechnology DOT info

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