A few weeks ago I saw an ad in the German magazine c't
about a so-called Videostreamer. This is an interface
between a PC's parallel port and any video-recorder for
backing up your data on a videotape. The company (DataSave?)
claims that it can store up to 7 GB on a 300 minutes tape.
                         ^^^^^^^^^^

It costs DM 250.- (about USD 200, I think)

My question is:
 Does anybody use this product, if yes, how many bytes 
 REALLY fit on a 300 minutes tape (7 GB sounds quite
 unbelievable to me). 

However, any comments on the interface are appreciated.
Please mail your replies directly to me, I will sum up
if neccesary. Thanks in advance...