Okay, for starters, I've switched to 1.2G in my attempts.  It clearly has
a much better suite of tools available on the installl floppy (and it's 
closer to current if we find any bugs anyway).


Now for the interesting part.  If I do the install "manually", I seem to
clobber the MBR after "installboot".  Below are the steps:


1) fdisk the disk using 707/32/63 as the geom.  Everything goes well, and
   I end up with the following fdisk output:

---
******* Working on device /dev/rwd0d *******
parameters extracted from in-core disklabel are:
cylinders=707 heads=32 sectors/track=63 (2016 sectors/cylinder)

parameters to be used for BIOS calculations are:
cylinders=707 heads=32 sectors/track=63 (2016 sectors/cylinder)

Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 0 is:
<UNUSED>
The data for partition 1 is:
<UNUSED>
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
sysid 165 (NetBSD or 386BSD)
    start 1, size 1425311 (695 MB), flag 80
        beg: cylinder    0, head   0, sector  2
        end: cylinder  706, head  31, sector 63
---


2) Install the following disklabel (with "disklabel -w -r wd0a mywd")

---
mywd|NetBSD installation generated:\
        :dt=ST506:ty=winchester:\
        :nc#707:ns#63:nt#32:\
        :se#512:\
        :pa#1171296:oa#0:ta=4.2BSD:ba#8192:fa#1024:\
        :pb#254016:ob#1171296:tb=swap:\
        :pc#1425312:oc#0:\
        :pd#1425312:od#0:
---

   ``disklabel'' asks "Erase the previous contents of the disk?"
   I answer "y".


3) "disklabel -r wd0a" confirms (?) that the label was written

4) "newfs /dev/rwd0a" does its job.

5) For kicks, I populate the file system with the binaries from the install
   floppy

6) Now the weird part.  I intsall the bootblocks with
   "/usr/mdec/installboot /usr/mdec/biosboot.sym /dev/rwd0a" and after it
   completes, I end up with the following ouput from fdisk:

---
******* Working on device /dev/rwd0d *******
parameters extracted from in-core disklabel are:
cylinders=707 heads=32 sectors/track=63 (2016 sectors/cylinder)

parameters to be used for BIOS calculations are:
cylinders=707 heads=32 sectors/track=63 (2016 sectors/cylinder)

Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 0 is:
<UNUSED>
The data for partition 1 is:
<UNUSED>
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
sysid 165 (NetBSD or 386BSD)
    start 0, size 50000 (24 MB), flag 80
        beg: cylinder    0, head   0, sector  1
        end: cylinder 1023, head 255, sector 63
---

It looks like it's clobbering the MBR.  If I don't install the bootblocks,
fdisk output remains as before, and a reboot off the HD predicably has 
the result: "Missing operating system".

If I write the bootblocks, I'm back to "Read error", but it clearly has
clobbered something, so that's to be expected too.

Just a note:  I check the output of "fdisk" after each stage.  It's definitely
the "installboot" that produces the change, not anything else.

Any further thoughts?


-wps