Kevin Ernst wrote: > Also, I gather DDS drives are supposed to have more sophisticated and > reliable tape-and-head alignment mechanisms, Rather, since they are helical-scan devices, alignment is not as critical, since they aren't trying to lay down parallel tracks on the tape (which is where alignment comes into play). The need for absolute vertical alighment is why linear tape media such as QIC and SLR have large metal base plates to keep vertical alighment constant. I dislike DLT too much to figure out how DLT solves this problem. (Sorry, just a case of perusing the DLT SCSI specs... should be called "DUMB linear tape", for how little functionality is provided to operting systems and applications programs). The theoretical disadvantage of helical scan devices is shorter tape life, due to the extra wear of having to go over a wide swathe of head at high speeds. It may be that helical scan tapes don't store as long either due to the tighter horizontal packing of bits. Both of these are so dependent on media material and composition, and tape head composition, that it's hard to make a tried-and-true rule here. > stores 4 gigabytes natively, which is just fine by me. As far as I > know, DDS drives are always backward compatible for reading and > writing older DDS format tapes, so you'll never have to ditch your > old media if you upgrade your drive. Note that this is not entirely true. Somewhere in the DDS line there was a media change similar to that in the QIC world, where the old tapes can be read, but not written, by the current drives. I'd have to check, but I suspect that DDS-4 tape drives cannot write DDS-2 or DDS-3 tapes, and absolutely cannot write DDS-1 tapes (which do not have the proper media recognition system). Nevertheless, one of those surplus DDS-2 drives is still a bargain if you have no need for more than 4 to 8 gb of storage (assuming that you're willing to undergo one tape change or split your backups into two pieces, which is that max that most people are willing to do). > I'm actually thinking about chunking my Ditto Max as a paperweight > and getting a used DDS drive. Not that my Ditto Max hasn't been > working exceptionally under Linux (ftape-4.02)--it's just that the > media is too expensive. Don't forget the speed difference. Nobody has ever accused a Ditto Max of being fast. The wonder is that it works at all :-). -- Eric Lee Green There is No Conspiracy [EMAIL PROTECTED] http://www.badtux.org
