how good is the data reliability with CD ROM and DVD RAM?

I wouldn?t touch 4mm DAT tapes with a ten foot pole, if I can help it. I?ve used them in the past, but only in special cases, OR more importantly when forced to. You can?t buy new LTO2 or DLT drives (I think the last DLT drives were DLT8000?s). Even Super-DLT tapes are obsolete. At this point, for tape, I recommend LTO8, and if this is for Archival purposes, you?ll need to refresh to LTO9 when released. LTO8 introduces an evil little gotcha. While previous versions of the drives, have been able to read two versions back, LTO8 can?t. I?ve failed to see any reason behind your questions. If you?re looking for a long-term archival solution, look to cloud storage (either on-prem, or off-prem). Sure tape is cheap, but when you start looking at other costs, such as storage and handling, it becomes expensive. This touches on one of my personal projects this year. I virtualized my backup infrastructure for my OpenVMS systems, and then I went a step further, and have virtualized most of my OpenVMS environment. I still need to virtualize my DECnet area router. While all the data is moved, I?m still working to move some apps. It makes protecting my data easy. My primary interest is the OS and software, while in the past I?ve been focused on running on real hardware, virtualization is looking real nice, even for working systems where I have plenty of spares. Zane