burncd -- possible problem

[Malcolm Kay]

I'm not sure whether I have a problem burning CD-Rs -- certainly
I don't understand what I observe.

The OS is FreeBSD 4.7-release.

I take a commercial CD-ROM and copy it as an image with:
# cp /dev/acd1c natins.cd
which creates the file natins.cd of around 673400*1024 bytes 
without any apparent problem. (I can't remember the exact size
but was certainly a multiple of 1024).

# md5 natins.cd
and
# cat /dev/acd1c | md5
produce identical results.

Now inserting a blank CD-R:
# burncd -f /dev/acd1c data natins.cd fixate
runs apparently normally and without error.

But now
# cat /dev/acd1c | md5
produces and IO error and a different checksum

# cp /dev/acd1c natins.back
produces the same IO error and a file 8*1024 bytes
shorter than natins.cd.

If I strip off the last 8k from natins.cd and compare the
result with natins.back I find they are the same.

When I look at the last 8*1024 bytes stripped from natins.cd I 
find these are all zero (ie NUL).

Re-running burncd on a new CD-R blank repeats the result 
exactly; i.e. IO error 8k short of the size of the original but the
rest matching.

As a mounted cd9660 file system the copy appears normal and 
the visible files test identical to those on the original.

Questions:
Is what I'm observing normal when writing with burncd?
Do I have a hardware problem?
Is this due to some bug in burncd?

Should I worry about this or just ignore?

Malcolm Kay