[Bug-tar] unusal bug in tar 1.14-1.15a

[Christopher B. Strong]

I have found what appears to be a new bug in tar-1.14, 1.15 and 1.15.1

I have not found documentation of this bug in 1.15.90 or 1.15.91, so I 
assume has not been corrected.

If I issue the following command:

tar -c -v -b 512 -M -f /dev/st0 .

Under tar 1.13, it works fine.

Under 1.14, 1.15 or 1.15.1, it prompts me to change the volume after 
writing only a small amount of data; the tape does not even move, so I 
assume it's less than 256K.

If I omit the "-M" command, it writes just fine until it runs out of tape.

If I omit the "-b 512", it writes just fine, but is very inefficient 
with this tape drive; plus the 256K block size is what I have selected 
to use for our existing archive.

If I write it to a file, rather than a tape, it works fine.

Please advise.

Thanks!
Christopher Strong