I, too, appear to have bad bits of hardrive that are tripping me up.
I'm trying to install NetBSD 1.3 on a Quadra 630 with 20MB ram. I
repartitioned a 1 gig drive with the required swap partition [40MB] and
root&user partition [290MB].

When I use Mkfs_1.45 to install base.tgz, I get this cryptic message
about 80% near completion:

-r--r--r--     3/7         10274 Thu Jan 01 02:32 1998 ./usr/lkm/fdesc.o
-r--r--r--     3/7         33763 Thu Jan 01 02:32 1998
./usr/lkm/if_ipl.o
-r--r--r--     3/7          9360 Thu Jan 01 02:32 1998
./usr/lkm/kernfs.o
-r--r--r--     3/7          7812 Thu Jan 01 02:33 1998 ./usr/lkm/mfs.o
-r--r--r--     3/7         41918 Thu Jan 01 02:33 1998
./usr/lkm/msdosfs.o
-r--r--r--     3/7          7143 Thu Jan 01 02:32 1998
./usr/lkm/nullfs.o
-r--r--r--     3/7          8392 Thu Jan 01 02:32 1998
./usr/lkm/portal.o
-r--r--r--     3/7         14286 Thu Jan 01 02:33 1998
./usr/lkm/procfs.o
-r--r--r--     3/7          7972 Thu Jan 01 02:33 1998
./usr/lkm/umapfs.o
drwxr-xr-x     0/0             0 Wed Dec 31 23:47 1997 ./usr/local
mkdir : File exists
drwxr-xr-x     0/0             0 Wed Dec 31 23:47 1997 ./usr/local/bin
mkdir : File exists
drwxr-xr-x     0/0             0 Wed Dec 31 23:47 1997 ./usr/local/lib
mkdir : File exists
drwxr-xr-x     0/0             0 Wed Dec 31 23:47 1997
./usr/local/libdata
Error on SCSIRead(), # 5
Error on SCSIWrite(), # 5
Error on SCSIRead(), # 5
Error on SCSIRead(), # 5
Error on SCSIWrite(), # 5
Error on SCSIRead(), # 5
pos = 0, i = 27, fs = /
alloccgblk: can't find blk in cyl

Assuming that it is a bad sector problem, my questions are the same as
the previous chap's with bad blocks:
Can Mkfs fix it? 
Can this be fixed without reformating the entire drive? 
Is there a Mac disk utility that can see the BSD partitions and format
them? FWB and APS can't: At least not in my meager hands...
[I used FWB HDT and did a Quick Format instead of a Low Level, in order
to save time]

Thanks...