It is possible to still use a hardisk even if track 0 is bad.  In the 
manufacturing of hard disk media it is not unusual to have 10% of the
total disk space unusable as bad tracks. So in a 10 meg drive  100,000
unusuable sectors is not considered bad. If you have a disk that has less
bad sectors than this then consider yourself luck. If you disk is clean
then consider that unusual. In a full height drive the error rate is less
and it is not unusual to have a clear disk with 0 bad tracks. Use a product
like scavenge or Nortons Utilities to isolate these bad tracks. If your bad
track is at track 0 all is not lost. Although fdisk from msdos or ibm formats
tracks from 0 to xxx cylinders and then will create up to 4 hard disk 
partitions starting at the first sector you can use fdisk 
to create a partition of 0 to 2, use the remainder as the dos partition and set
this to be the active partition. The disk is still usuable for dos although 
not bootable since if you reformat then all partitions are lost. 
However Digital's
CPM 86, or concurrent CPM also allows you to set up partitions, for CP/M and
DOS but in this case the CPM and dos partitions are formatted AFTER they are
designated. Thus you can designate a DOS partition from 2 to 
xxx cylinders, have 
CPM/86 format it in dos and transfer the system . THe disk is now bootable. My
33 meg has tracks 0-3 bad. Thats the boot sector and dir tracks. By using CP/M
86 to do the initial partitions I am able to reformat only the dos partition, 
in this case from 4 to 653 , transfer the system and it boots with no trouble.

Nathan Goldenthal