Patrick,

> Is there anyone using LTO2 drives with LTO1 tapes?
Yes - we've been using it to migrate from LTO1 -> LTO2. No problems 
encountered. We replaced all LTO1 drives with LTO2 in one go (with TSM 5.1.6.3 
at that time).

> How does the transferrate changes?
Not much, loading (and TSM labelling!) is much faster, datarates are about the 
same with LTO1 tapes.

> LTO2 drives with LTO1 tapes work??
> I have heard that the maximum speed for this case also would be 15MB/s.
LTO2 drives support variable speeds with LTO1 media as well (as I understand 
it) so there would be less prone to stop/start waits when the data rate does 
not much the tape transfer rate. We didn't measure gain with our LTO1 media 
because once we had the LTO2 drives in, the LTO1 media was set read-only.

> But what is the difference? Is the rotation of the drive slower?
More tracks per inch, different technology for the LTO2 media. Please checkout 
the LTO.org website.
LTO1 uses RLL1,7 as recording method, where LTO2 uses PRML.

> Does anyone know, if there are compatability problems combining those two
> technologies?
None whatsoever noticed. Be aware that compatibility is a design constraint 
within the whole LTO roadmap (see www.lto.org , or specific: 
http://www.lto.org/newsite/html/about_faqs.html)

Quote:
Q9: What are the backward compatibility characteristics of the Ultrium format 
Generation 2?
A9: The LTO Ultrium compatibility is defined with two concepts demonstrating 
investment protection:
  1) An Ultrium drive is expected to read data from a cartridge in its own 
generation and at least the two prior generations. 
  2) An Ultrium drive is expected to write data to a cartridge in its own 
generation and to a cartridge from the immediate prior generation in the prior 
generation format. 

For example: 
 - An Ultrium format Generation 2 drive will read and write data on an Ultrium 
format Generation 1 cartridge as specified by the Generation 1 format. 
 - An Ultrium format Generation 2 drive will read and write data on an Ultrium 
format Generation 2 cartridge as specified by the Generation 2 format. 



Marcel Anthonijsz
Shell Information Technology International B.V.
PO Box 1027, 2260 BA  Leidschendam, The Netherlands