Problem : archecker with compressed archive

Hello Forum, I am experimenting with compressed Level-0 archives which are generated like this : ontape -s -L 0 -t STDIO | gzip -qc > ontape-L0.gzso far so good - to verify the archive or to restore something from it, I don't want to inflate the compressed archive but the command gzip -qcd ontape-L0.gz | archecker -stdv # AC_TAPEDEV is set to STDIO leeds to strange and different results - sometimes I get a simple "Scan FAILED" even without recognizing the Tape type or the archive level or date, the next run on the same file says "Scan PASSED" and "Table checks FAILED" or "Table checks PASSED" without recognizing any table - the other time some hundred tables are reported as validated. Informix 10.00.UC5I1 on SuSE Linux 9.3 (i586) I hope this is understandable Stefan P.S.: it works fine with the uncompressed archive : archecker -stdv < ontape-L0