Defining Disk Image Dump Standard

From: allisonp <allisonp_at_world.std.com>
Date: Tue May 30 19:28:12 2000

>If you're serious about creating an archive. It needs to be permanent, so
>it's essentially requisite that the media be write-once. I'd say you're
>better off with an OTP EPROM. Hardware to create them is dirt-simple to
>create, eraseable/rewritable equivalents are readily available, and even if
>the OTP's (very inexpensive, by the way) become scarce, there will still be
>rewritables available which can be write protected by removing the VPP or
>program pin. Use those and you'll have a real archive. What's more, there
>are no mechanical components, nothing to rust, become misaligned, or wear
>out.


Your kidding? Right? Eproms, have a finite random failure rate and while
better
in some ways over time you still run the risk of total failure due to:

 Environment, humidity increases failure rate.
                        Temperature
                        Time
                        Electrical stress.

This does not include ESD and circuit mishandling. it still assumes
compatable technology (try reading a ECL prom using TTL).

Add to this the great number of devices needed to contain said archive
your risking the boat in exactly the same way as CDrom or on shorter
time spans magnetic media.

All of this is seperate from the format that will assure recovery of the
data.

Myself I'd rather risk even floppies with their known weakness and use
redundant recording and added error detection/correction. Even when
applied to CDroms this is more viable.

Most of all it matters not what you do, what you do it on! It does matter
that sufficient data on what was done is available along with the archive
to reconstruct not only the data but the systems that archived it (or can
recover it!!!). Books work because they can be preserved and copied
if they start to decompose and we teach the languges needed to read
them.

Reminds me of an old theological arguement of how many angles can
dance on the head of a pin. Untill we have music, a pin and angles
it's simply an exercise with a meaningless outcome to all but the faithful.

Allison
Received on Tue May 30 2000 - 19:28:12 BST