[ Date Index ][
Thread Index ]
[ <= Previous by date /
thread ]
[ Next by date /
thread => ]
Jon Still wrote:
The good news is DDS-1 tapes are highly portable, and can be read be all later DDS standards! The bad news is they aren't very long.I understand this is 2GB raw, 4GB uncompressed. What can I use to compress the data - is gzip going to play nicely with tape devices?
Typically DDS devices do their own compression, but yes you can pipe stuff through a compression tool first, it'll be more efficiently compressed by gzip, what effect it'll have on throughput or memory demands is another question. I forget the terminology, "line compression"?, I think the devices do little more than spot short duplicated sequences to get their alleged 2 fold compression. The claim was always a factor of 2, and they usually used the higher number for marketing. I thought DDS-1 was 1GB raw, nominally HP sold 1.3GB tapes at 60 meters length. Quick Google suggests DDS-1 (Hey isn't it just DAT at that point?) tapes seem to be available that are longer than 60 meters. It is perfectly possible, indeed likely, that the 60 meter limit was to do with reliability than a technical limitation, but I seem to remember not using more than 60M with DDS-1 for some reason. -- The Mailing List for the Devon & Cornwall LUG Mail majordomo@xxxxxxxxxxxx with "unsubscribe list" in the message body to unsubscribe.