Paul Mather wrote: > By definition, random data are not compressible. It's my understanding that > the "compressed capacity" of tapes is based explicitly on an expected 2:1 > compression ratio for source data (and this is usually cited somewhere in the > small print). That is a reasonable estimate for text. Other data may > compress better or worse. Already-compressed or encrypted data will be > incompressible to the tape drive. In other words, "compressed capacity" is > heavily dependent on your source data.
Agreed. Looking at our library of around 100 LTO4 tapes, (800GB uncompressed/1600GB uncompressed), using hardware compression, the average full tape content is about 1000GB. >90% of the content is standard and high definition video frames - largely random. However there are some tapes with over 2TB on them, containing 2 bit images where large areas of the frame are the same pixel value. Regards, Richard ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Bacula-users mailing list Bacula-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-users
