<sklower@vangogh.CS.Berkeley.EDU> for the following, related to the -z (zero)
option in imageunzip/frisbee:

  1. For the case where a full-disk image is smaller than
     the disk the image is being unzipped onto, we added
     code to zero the area between the end of the image and
     the end of the disk.

  2. During the unzipping process, when zeros are being written
     at the end of a chunk, a write() that returned a length
     different from the expected value previously caused an
     infinite loop.  We noticed this problem at ISI, on a number
     of pc733s, which we suspect may have (relatively minor)
     hardware disk problems.

The latter addressed a Mike-o that has existed for 4 years.  Call it failure
resilient computing or just plain denial, but because of a botched conditional,
I was ignoring failed writes to the disk.  This lead to one of those infinite loop
thingees if you actually had a bad disk.