blocking factor

[bkohler51]

I am using Jtar in an application to tar a directory of files in windows. Analysis of the file created indicates that it is using a blocking factor of 3.
The application that extracts (tar -xfv filename) runs on a hpux box and apparently uses the default block size of 20 but is giving me the error "Tar: tape blocksize error". And when I use tar bxfv -b 3 filename, it works.
The problem is I can't change the extract application to use that factor so I need to know how to do it with Jtar on the front end so the default will work on the back end.
Thanks Bob

[bkohler51]

Did some more research and found Jtar only writes with a factor of one. So I created my own copy of Jtar with a modification to TarOutputStream class that would allow a blocking factor.
Added
private int blockingFactor;
...changed
public void close() throws IOException {
closeCurrentEntry();
write(new byte[TarConstants.EOF_BLOCK]);
//Now pad it to a multiple of the blocking factor
int blkFacSize = TarConstants.DATA_BLOCK * blockingFactor;
write(new byte[blkFacSize - ((int) (bytesWritten % blkFacSize))]);
super.close();
}
...Added
public void setBlockingFactor(int factor) {
this.blockingFactor = factor;
}

[kamranzafar]

Thanks for your contribution, I will try to incorporate the blocking factor change in next release.