better disk reliability on a desktop machine

[Chuck Swiger]

Stephen Hilton wrote:
> Chuck Swiger wrote:
[ ... ]
>> Sure.  But a single spare HD is a single point of failure.  Having one 
>> tape per week or per month going back 10 or 100 tapes gives much more 
>> redundancy....
> 
> But were the tapes all generated by the same tape-drive? if so it is
> once again a potential single point of failure. The created tapes
> may not be readable by any other drive due to mis-alignment etc...
> if that tape drive fails, the data on the tapes is lost also.

It is true that tape alignment problems can make tapes unreadable, but the 
frequency of that sort of problem varies a lot by format: helical scan tapes 
such as DAT tend to have a lot more problems then linear formats like DLT or 
LTO/Ultrium.

It is also a lot more likely that a data recovery company can make something 
out of a backup tape written by a misaligned drive than what you usually get 
from a blown hard drive.  People design tapes, tape drives, and the on-media 
data format against the common sources of tape read errors, in part by using 
ECC prudently (again, the quality here can vary by format, and by the backup 
software being used).

-- 
-Chuck