The 540 did come with a SCSI card (the acorn one that worked with RISCiX)
but that one was never so hot for speed... I suspect it was one of my own
scsi cards (I made and sold these way back).

I didn't reserve any blocks at the start of the drive though - when filecore
asked for sector zero, it got it - so I'm not sure there's even a partition
table. When I mounted it under linux, I didn't need to specify an offset -
it just worked.

The ADFS disk record at byte offset 0xdc0 appears valid, by manual parsing:

log2secsize=9 (512 bytes)
secspertrack=0x20 (probably immaterial on scsi)
heads=4 (again, probably immaterial)
density=0
idlen=0xf (any ideas?)
log2bpmp=0xb (2048 bytes... kinda could be reasonable, I guess this is the
allocation unit?)
skew=0
bootoption=0
lowsector=0
nzones=0x3f (allocation zones?)
zone_spare=0x20
root=0x27f (root dir offset sector? can't see anything that looks like a
rootdir at sector 27f though)
disc_size=0x1f000800 (520 decimal MB, which is correct)
disc_id=0
disc_name=null (hmm... usual?)
disc_type=0
disc_size_high=0

etc etc all zero. I have not hand-calculated the checksum but as it mounts
under linux I guess this is right.

It does look like there was some junk on the drive which is possibly there
from Fuji's factory test or similar - ie there's stuff in sector 0 and 7
which appears identical (and maybe is only there because nothing ever wrote
to it).

Would be great if there was some sort of error reporting in ADFS :)

Thanks,
Hugo

On Tue, Mar 1, 2011 at 12:18 PM, Ralph Corderoy <[email protected]>wrote:

>
> Hi Hugo,
>
> > Does anyone have any idea what ADFS looks for in the boot sector? The
> > image appears to be complete, I believe it was from either my A540 or
> > RISCPC, and it's mountable under linux without issue.
>
> The Risc PC didn't have SCSI support IIRC, and I've an odd idea the A540
> may have come with a SCSI podule?, have you any idea who manufactured
> the SCSI podule this drive it would have been connected to?  Acorn did
> one, Oak did another, don't know if there are more.  (Mine was Oak.)
>
> When you say it's mountable under Linux, does that mean
>
>    mount -o loop mnt acorn.img
>
> just works or did you have to specify an offset into the image?
>
> > In case it sheds any light, here's the first 32k od'ed (lots of zeros
> > omitted, obviously!).
>
> At first glance it looks a bit odd.  If Linux handles it then I guess
> the drive's particular partition scheme, there were various, must be in
> http://lxr.linux.no/#linux+v2.6.37.2/fs/partitions/acorn.c
>
> Cheers,
> Ralph.
>
>
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