17 Jul
2023
17 Jul
'23
9:58 a.m.
On Mon, Jul 17, 2023 at 12:48 PM Ethan Dicks <ethan.dicks(a)gmail.com> wrote:
On Mon, Jul 17, 2023 at 12:28 PM Henry Bent via
cctalk
> I'm almost thoroughly unfamiliar with IMD - is there some obvious
> extraction/conversion option that I am missing here?
As mentioned previously, yes. There's an additional step that has to
happen to any direct imaging of RX50 disks. John Wilson's PUTR
happens to do this convolution internally.
If you desire is to snapshot physical media for rewriting later, IMD
is excellent. If you want logical-block-order files for simh, you
need one more step (keep reading).
Were these disks actually imaged correctly? I would
appreciate any suggestions.
Yes they were.
From: http://www.chdickman.com/pdp11/pro380.txt
"The RX50 floppy starts at track 1. Track 0 is logically placed after
track 79. The sectors are interleaved 1, 3, 5, 7, 9, 0, 2, 4, 6, 8,
10. The track shift and interleave must be taken into account when
moving disks between real PDP-11 and emulators."
I have had good luck with a secfor convolver from the same page as this comment:
http://www.chdickman.com/pdp11/lbn2rx50.c
It will go both ways, to and from physical block order and logical block order.
Cheers,
-ethan