Archiving Data Permanently

[Mike McCarty]

Ezra Nugroho wrote:
> I kinda doubt it.
> 
> HDs are now built with precisions and standards that are equal or exceed
> those of jet engine making. Consider the engineering that people use to
> make micro HDs for IPods, etc.

This is not an apt comparison. People do not leave jet engines idle
for five (5) years, and then expect them to start right up and work.

> Tape cassettes only use a lot of moving objects. Not only that, the tape
> touches it self in the roll, the head of the reader touches the tape.
> This means wear and tear. Furthermore, tape is magnetized plastic. They
> are less heat resistant.

As I mentioned before, tape is very reliable. It has been shown to have
20+ year retention. One gets "wear and tear" only when the tape actually
moves. For data archival purposes, this is effectively never.

Note that the topic here is archival, not repeated backups.

> HD heads now float above the platters, they do not touch the platters at
> all. HDs are air tight.

Not when they are powered down, they don't. The heads sit right on
the landing track.

> The only advantage that tape has over HD is in shock resistance.
> The cassette may break from a drop, but you may still (expensively)
> recover the data from the tape, if it is not damaged.

This is, unfortunately, untrue. A shock great enough to damage the
case severely may also cause a thing called "edge damage", which
is often unrecoverable. But that takes a much greater shock than
to damage a disc, mostly because the case of a disc has very little
"give", and transfers the shock right on to the platters.

Mike
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