> I've been trying to generate the basic block vectors using the
> code provided at
> http://www-cse.ucsd.edu/~calder/simpoint/simplescalar-bbv.htm.
> However, the .gz files generated appear to be invalid. What
> might be problem?

The tracker uses popen(3) to generate gzipped output:

sprintf( finalname, "gzip -c > %s/%s.bb.gz", outdir, outfile );
bbtrace = popen(finalname,"w");

You may have problems if your system does not support popen, or if
gzip is not in your PATH.

What does the .gz file look like? You can try the following commands
to get some information:

ls -l out.bb.gz
file out.bb.gz

gzip -t out.bb.gz
less -S out.bb.gz

-jeremy