> > Yes. VERY IMPORTANT! Yet almost noone bothers to do it. NASA has tons
> > (literally) of data that is decaying into worthlessness, because they
> > didn't have viable plans for long-term retention.
>
> Is this really true or just another legend? I ask because many people
> also say that the old data the Census Bereau keeps in digital form is also
> decaying and partially unreadable.
>
The NASA one is definitely true. I was at a NASA workshop
sometime around 1990 where this was discussed. One of the
problems we discussed was actually using the data before it
became unreadable. At that point it was estimated that only
5% of the data collected by NASA was ever read. There were
several reasons stated for this:
1) NASA is very conservative in data collection, they always
collected more data than they need. The main reason for
this is the cost of sending out a probe, you don't want
to miss something important and have send another one.
2) There is a considerable time delay in programming a probe.
The probes can be programmed after launch, but due to the
distances involved (and slow transmission rates), it can
take a considerable length of time to send a new program.
At that time (1990), the probes were programmed several
weeks in advance. Again, if you see something interesting
coming for the probe, there is no time to reprogram it, so
you had better collect everything.
3) The volume of data was far too large for anyone to look
at. NASA was looking for better ways to visualize the
data, so more could be examined before it was lost. This
is the main reason why I was at the workshop.
--
Dr. Mark Green mark_at_cs.ualberta.ca
Professor (780) 492-4584
Director, Research Institute for Multimedia Systems (RIMS)
Department of Computing Science (780) 492-1071 (FAX)
University of Alberta, Edmonton, Alberta, T6G 2H1, Canada
Received on Tue Jun 13 2000 - 20:44:13 BST