Mounting old BSD filesystem

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

I have an Acorn A680 [1] which runs RISCiX which is a BSD 4.3 variant from 
1989. The hardware itself is currently not well (magic smoke problems), 
but the SCSI disk is fine. I have taken an image of it (using 
NetBSD/acorn32!).

dumpfs recognises it as a FFSv1 filesystem (mildly surprised as wasn't 
sure of partitioning, if any).

file system: /dev/vnd0a
format  FFSv1
endian  little-endian
magic   11954           time    Thu Nov 21 13:09:49 2002
cylgrp  static  inodes  4.2/4.3BSD      sblock  FFSv1   fslevel 0
nbfree  1938    ndir    160     nifree  6061    nffree  11
ncg     5       ncyl    160     size    40960   blocks  39603
bsize   4096    shift   12      mask    0xfffff000
fsize   1024    shift   10      mask    0xfffffc00
frag    4       shift   2       fsbtodb 1
cpg     32      bpg     2048    fpg     8192    ipg     2048
minfree 1%      optim   space   maxcontig 1     maxbpg  256
rotdelay 4ms    headswitch 0us  trackseek 0us   rps     60
ntrak   16      nsect   32      npsect  0       spc     512
symlinklen -1   trackskew 0     interleave 0    contigsumsize -1
maxfilesize 0xffffffffffffffff
nindir  1024    inopb   32      nspf    2
avgfilesize -1  avgfpdir -1
sblkno  16      cblkno  24      iblkno  28      dblkno  284
sbsize  2048    cgsize  2048    offset  16      mask    0xfffffff0
csaddr  284     cssize  1024    shift   8       mask    0xffffff00
cgrotor 4       fmod    0       ronly   0       clean   0x00
wapbl version 0x1       location 0      flags 0xffff0002
wapbl loc0 18446744073709486083 loc1 18446744073709551615       loc2 
18446744073709551615       loc3 18446744073709551615
usrquota 18446744073709551615   grpquota 18446744073709551615
flags   none
fsmnt   /
blocks available in each of 8 rotational positions
cylinder number 0:
   position 0:      0    4    8   12   16   20   24   28   32   36   40   44   48   52   56   60
   position 2:      1    5    9   13   17   21   25   29   33   37   41   45   49   53   57   61
   position 4:      2    6   10   14   18   22   26   30   34   38   42   46   50   54   58   62
   position 6:      3    7   11   15   19   23   27   31   35   39   43   47   51   55   59   63
cs[].cs_(nbfree,ndir,nifree,nffree):

        (616,31,664,0)
        (302,32,1179,3)
        (218,33,1557,3)
        (389,31,1083,1)
        (413,33,1578,4)

rump_ffs won't mount it:
# rump_ffs A680.vnd /mnt
rump_ffs: "A680.vnd" is a relative path.
rump_ffs: using "/usr/work/Software/Acorn/RISCiX/A680.vnd" instead.
[   1.0000000] entropy: ready
rump_ffs: mount: rump_ffs: puffs_daemon: Invalid argument
Invalid argument


I can share the image with anyone that is interested

[1] https://chrisacorns.computinghistory.org.uk/RISCiXComputers.html

--
Stephen