[Simh] 8" Floppy disk image getting HALT error

[Walker Sampson]

Hi everyone,

Let me preface this by saying that I’m unfamiliar with the original PDP machines. I work as a digital archivist and have received 8” floppy disks from which I need to recover data.

I believe I have recovered at least partial data from these disks; I’ve connected a Y-E Data 8” floppy drive to a KryoFlux floppy disk controller and gotten positive sector results setting the format to a DEC RX02 sector image. When I investigate the resulting disk image in a hex editor, I am seeing clearly a report document, so I don’t believe I have a false positive.

Outside of observing in a hex editor however, I don’t know how to access the disk or its contents. Using SIMH, I haven’t gotten the virtual machine to boot the floppy disk image.

Commands “AT RK01 <disk_image>” and then “BOOT RK01” give me a “HALT instruction, PC: 000002 (HALT)” message for the PDP-11 program. The PDP-8 stalls indefinitely and the PDP-10 outputs “Non-existent device” as well.

I can’t go back to the donors and ask what machines these 8” floppies were used with, so I’m not sure how to begin troubleshooting.

Any advice in that area is much appreciated!

Thanks,

Walker


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