response 51 of 61:

Aug 21 04:19 UTC 1997

Grex backups are currently made on 8 mm tape.  Actually, it seems that
zip disks would be cheaper (one source I just talked to says zip disks
are 1.8 cents each from meijers, after you get the mail-in rebate.)
Still, I'd have to say that getting a mail machine up and running, and
getting the 670 running, are higher priority.

More importantly however, would be considering exactly what kind of
disaster we are guarding against.  For instance, storing off-site
backups will protect against fire, flood, or other disaster (would you
believe a perfume explosion?) taking out the building.  Storing backups
in another city would protect against a larger natural disaster
destroying Ann Arbor.  Storing backups in another country would protect
against civil war, revolution, or a massive attack by a very unfriendly
and stupid foreign power.  One has to balance against this, the risk
that a particular disaster will happen.  For instance, a building fire
is certainly possible.  There are many other tenants in the building,
and some of them do smoke.  There is also a perfume distributor across
the hall from grex.  A flood is also possible.  The building used to be
an ice factory, and so has a very large water main running into the
building.  Off-site backups would be a good idea.

Other risks are not so high.  The huron river has never been noted for
flooding, and where I come from, would have been called a "stream" not a
"river".  Michigan is bare, wet and flat enough that the risk of a
forest fire or mud slide is pretty low.  Most tornadoes hit rural places
south of Ann Arbor.  The last "large" earthquake in Michigan was a
decade and a half ago, and produced less vibration than a large truck
going by outside.  In short, the risk of a large scale disaster hitting
Ann Arbor has got to be less than 1 every thousand years - or
infinitesimal compared to even an optimistic forecast of grex's expected
lifetime.

It's somewhat difficult to estimate the chances of some large scale
disturbance striking the US.  Certainly, the odds look pretty remote
right now.  So far as anyone can tell, the Canadians are not interested
in asserting their ancient territorial claims over Michigan or New York
State, and the Mexicans are not too interested in reclaiming their
northern provinces of California and Texas.  The south seems pretty
content to run chicken factories for the north, and not too many people
in Hawaii feel so strongly about restoring the monarchy that they're
throwing bombs through resort windows.  Cuba seems more interested in
the tourist trade than in the gun/rum runner trade.  While the odds of a
meteorite striking the US are pretty decent, the odds of something large
enough to cause the extinction of all the primates on the planet, or
even just Ann Arbor, appear to be pretty low, less than that of a civil
war between the smokers and the non-smokers.

Besides, anything large enough to destroy the US is almost certain to
render the internet unusable, and will probably leave any surviving grex
members with more important things to do than to worry about grex.

response 53 of 61:

Aug 21 10:58 UTC 1997

But Marcus, you forgot the Puerto Ricans!  It was only, what, 40 years ago
that they shot up Congress.

response 55 of 61:

Aug 21 12:43 UTC 1997

I can believe that regular 1.4 MB floppies can be had for 1.8
cents after rebate.  Can anyone confirm that 100 MBZip disks 
are available for less than $15 each?

response 57 of 61:

Aug 22 15:44 UTC 1997

The impression that I get is that zip disks suck. Certainly the concept is
suspect, being essentially a hard drive that you remove the disks from. Not
very robust. Instead, go for optical media.

As for UPSes, the ones I've heard about use (surprise!) lead-acid 12 volt
batteries. This, the endurance of a UPS should be indefinitely expandable just
by adding used car batteries. (Car batteries are typically in the 60 amp-hour
range.)

response 59 of 61:

Aug 22 20:24 UTC 1997

There's no inherent reason a zip disk should "suck" any more than a tape
drive.  High quality media and cleanliness are important, in both cases.
A zip disk does have a very important difference from a traditional
winchester hard disk.  In the winchester, the disk is a rigid aluminum
plate.  The head is generally even more rigid, consisting of ceramic
materials.  That means if for any reason (shock) the two should contact,
there is a high probability of data loss.  In a zip disk, the disk is
flexible, and in fact, the design of the unit *requires* that the disk
be flexible (if I remember right, the disk is microscopically deformed
as it passes over the head).  Because the disk is flexible, occasional
media contact is not a disaster, but at most will cause transient I/O
failures.  This makes the drive much more shock resistant.  It also
means the zip disk is a fundementally different kind of technology than
traditional removable pack winchester drives (which do tend to be kind
of finicky.)

Yes, you sometimes *can* add lead-acid 12V batteries; but not always,
and certainly not infinite quantities.  The limit is the charging
capacity of the unit.  If the unit is "smart" in the wrong way (for
instance, having a microprocessor that "knows" how long to charge the
batter, rather than looking at the voltage to decide this), the unit
might just plain not work right.  It would make more sense to use a new
car battery, and wherever the batteries are kept should be well
ventilated (to prevent the built-up of dangerous amounts of hydrogen
gas.)

response 61 of 61:

Aug 24 19:02 UTC 1997

Marine or RV batteries then. A bit more expensive.

Those considering an Iomega product should at least peruse comp.sys.scsi for
a while before deciding.