Re: How to care for an old computer?

[mjmahon@aol.com (Michael J. Mahon)]

Ernest wrote:

>As computers age, is there anything that we can do to keep them running for
>the long term? By that I mean, what parts are most likely to stop working,
>and can we do anything to prevent it? 
>
>My guess is that the power supply and ROM chips wwould fail first but I
>haven't had any ROMS fail yet (bit rot.) Power supplies go out but those
>can be repaired. What about the memory chips? Or the 74x's?
>
>The ROMs can be copied to .dsk images. Mechanical things can be fixed or
>remade but the is there anything else that one should worry about, beyond
>the obvious?

ROMs are a potential issue, since they have proprietary content that
is not replaceable off-the-shelf.  Fortunately, their images can be (and
many have been) preserved.

In machines with proprietary gate arrays and ASICs, like the later
Apple II series, these constitute irreplaceable chips, since they are
no longer being made.  Functional replacements could be created
by reverse-engineering, but the process would be difficult and the
resulting packages would require adaptation--probably this will never
be done.

Power supplies are certainly the most likely things to fail, but they
are easily replaceable, since more modern equivalents will always
exist that could easily fit within the original box if desired.  And,
old ones can be repaired, too.

Damage to the circuit boards from corrosion or wide temperature
excursions would be a long-term issue, but these problems can
usually be controlled by the owner.

Over all, I would expect a low failure rate for electronic devices
of this vintage, for at least the next 20-30 years.  After that, we
may be learning about hermeticity and passivation failures in
late-20th century IC production processes.  ;-)

My guess is that that term pretty will covers your question, but
I can't help but speculate about the longer term...

Ultimately, emulation will be the safe harbor for older computers.
Some emulation may be done at a hardware interface level to
permit continued use of surviving period peripherals.  But most
emulation will be software emulation on more modern machines
supporting "images" and other emulations of some peripherals.

We can hope that much of the software currently extant will
survive, simply by replication onto newer media.  The primary risk
is the currently misconstrued notion of intellectual property which
would "let the software rot in order to protect it".

Much of the period hardware will wither into non-working museum
pieces eventually.  How much of it survives physically depends on
how much interest is maintained by the culture.  Given that it is
regarded today as trash, and given the still fairly large quantity of
Apple hardware remaining, I'd say that we still have a generation
or more of "throwing it out" before we need to get serious about
preserving what's left for museums of the future.

-michael

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