Posted by Eins on February 24, 2001 at 08:29:57:
In an ideal world, both computers would be the same. In a realistic world, there is a new one and an older one, and both are not of the same conservatism. So, which one would you use as a backup? (Forget for a moment that the newer one has the better features and therefore qualifies as the primary).
My though is: what do you bring a backup for in the first place? If it is to be able to continue diving after your primary dies, then it is the better idea to use the conservative one as backup.
Otherwise, in an extreme situation, a diver on multi day diving has always dived to the limit of reaching NDLs (with his dprimary, conservative computer) while his liberal one has all that time indicated that there is more NDL. Now, after primary dies, this diver may continue to limit-dive with the liberal one. Guess what's going to happen to him on the next dive!
In any event, as long as computers are used intelligently, i.e., the diver has an understanding of decompression theory, and s/he dives responsibly, it does not really matter. To be on the safe side (and that is what backups are for?), it makes more sense to use a more conservative computer as backup.
Only problem is: some computers lock up when you don't follow their deco obligation.
So, what do you think?
Eins