[rescue] Using SCSI2SD on a Sun 3/110

Earl Baugh earl at baugh.org
Fri May 16 01:19:44 CDT 2014

Another note (keeping this as a separate thread, so as I work on both
approaches they hopefully don't get too tangled)

In my attempts to get the Sun 3 to boot, I've also been pursuing setting up
a disk image directly for the SCSI2SD board.

Based on comments from various folks, I figured it was worth trying to
directly build a UFS file system on the SD card that goes into
the board and give that a whirl.   First things, the latest Mac OS no
longer has UFS file support (that ended as of 10.5) so I had to come
up with another approach.

The best option (at least without another Sun to start from) I've found to
create a UFS file system was to get the FreeBSD virtual machine
image (fairly easily to Google and find it... contact me off list if you
need it) and work from that.

That I was able to import into Parallels (which involved basically creating
a new VM, telling it to work from the image you have... it then
converted it and gets stuff going).  From there, you can mount any standard
USB SD card reader via the Parallels Devices->USB menu.
>From there it was gpart time. I used gpart to delete any existing
partitions on the SD card, then re-created the gpart top mapping (gpart
and told it to use UFS (BSD is the type).   Then used gpart to add some
freebsd-ufs partitions to that (I don't know how to add the "c" partition
which represents the entire disk to the map... was able to make a root,
swap and 2 general partitions on the SD card.)

Copying files got a bit tricky.   Since the Mac can't read UFS anymore, I
had to stay within the FreeBSD image.  But mount_smbfs works to
mount an Apple share, so did that (after having to enable BRIDGED
networking for Parallels and rebooting the image) and can bring over files
from where I have them on the Macs (it's actually from a Windows 7 box that
acts as my NAS...)  So that lets me move files I want into the
FreeBSD image, and I can write them directly to the SD card.

However I'm then at a similar point as I was with netbooting.  What to put

Also, with the old boot PROM, there isn't any "probe-scsi" to check to see
if the Sun 3 even detects the card.
So, I haven't been able to sort out where any problems are in trying to
boot from the SCSI2SD.

If anyone has any suggestions as to how to verify that the card is good,
cabling is good, termination is good,
etc. esp on the Sun 3, it would be greatly appreciated.   So far the status
messages seem to indicate that
the drive isn't found, not that it's having trouble booting.  I've enabled
"TERM POWER" on the SCSI2SD card.
I turned off parity.  And I remembered the weird ID to sd mapping that was
present in Sun OS (ID 3 is SD 0, ID 0 is SD 3)
So have been testing both ID's and both sd(0,0,0) and sd(3,0,0) which I
believe are the correct things to specify
those two disks.

I did get confirmation from the SCSI2SD designer that I should be able to
directly use a disk partition that I've created
on the SD card on the Mac (via the FreeBSD path) since the card doesn't do
anything fancy, mapping wise, between
the SD card and the SCSI interface.   So, if I did have a boot image from a
Sun 3, I probably could try dd'ing it
back onto the card as well.   However, that gets back to the original
chicken-and-egg problem of trying to build
a boot disk :-)

So, similar overall problem... how to know what to put where... and make
the disk bootable...
Thoughts, comments, ideas all welcome..


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