On 7/17/23 09:28, Henry Bent via cctalk wrote:
> Hi all,
> 
> I just noticed that images of a full RX50 floppy set for Ultrix-32m 1.2 was
> posted on Bitsavers (
> http://bitsavers.trailing-edge.com/bits/DEC/vax/ultrix/1.2/ULTRIX-32M_V1.2_RX50_1986.zip
> ).  I am having difficulty parsing these images into a usable raw format
> for SIMH.
> 
> As a reference, TUHS has a set of 1.0 floppies (
> https://www.tuhs.org/Archive/Distributions/DEC/Ultrix-32M/ ) that are
> usable for installation purposes.  (You can ignore the 1.2 floppies in that
> archive, they aren't actually a full set).  The first disk of that
> installer, 32m-1.0-bin/01, has a bootloader that starts at byte zero as we
> would expect.  This should be approximately equivalent to disk 1 in the
> Bitsavers set.  Oddly though, in the "raw" dump the bootloader doesn't
> start until 0x1400, and a number of the other disks I looked at appear to
> have odd holes/zeroes in them.  IMD format dumps of the 1.2 disks are
> provided but when I converted the IMD format to a raw image I got the same
> issue.
> 
> I'm almost thoroughly unfamiliar with IMD - is there some obvious
> extraction/conversion option that I am missing here?  Were these disks
> actually imaged correctly?  I would appreciate any suggestions.

A quick glance at the RAW dumps tells me that the sectors are
interleaved.  I haven't checked to see if it's the standard FILES-11
interleave, but it looks likely.

--Chuck



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