Aug  1 15:40:59 dhcli-192-168-0-6 /netbsd: viaide0:1:0: lost interrupt
  Aug  1 15:41:01 dhcli-192-168-0-6 /netbsd: type: ata tc_bcount: 8192 tc_skip: 0
  Aug  1 15:41:01 dhcli-192-168-0-6 /netbsd: viaide0:1:0: bus-master DMA error:

[The error messages were (incorrectly) line-wrapped, apparently by
your mailer, so they are a bit hard to read.]

Those errors indicate that either

  NetBSD's driver isn't quite right (most likely)
  the controller chipset is buggy
  perhaps a bad cable
  the disk itself could have a flaky IDE interface

These errors don't indicate that the disk is bad in the sense of bad
sectors.

I suggest reading viaide(4).

-- 
        Greg Troxel <gdt@ir.bbn.com>