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Re: Fairness in marketing


Verily I say unto thee, that AZ Nomad spake thusly:

> But, don't you know that expensive power cables ... can not only
> modify the data to make everything better, but fix the checksums to
> match.

How might one justify this claim, I wonder?

In order for this to be true, the effect of /power/ would somehow have
to affect the integrity of /data/. The primary source of power problems
in a PC is the transformer, when one or more of the (usually) three
rails is not stable due to poor regulation.

So now we'd have to establish that:

a) ... A particular power cable has an enhanced ability to suppress
       transformer voltage irregularities, and
b) ... Transformer voltage irregularities can cause soft errors on
       datum.

Even then, we'd need to assume that the "fix checksums" claim is meant
to imply that it actually assists other components to prevent the
occurrence of such problems and/or implement an error correction
mechanism (such as ECC memory), rather than assuming that the cable
itself somehow directly alters datum.

Addressing point a) ... unless the cable is faulty (e.g. loose
connection) or not built to a specification rated for mains supply (IOW
as long as it actually works at all) then I fail to see how one power
cable can possibly be better than another, and therefore how it can
possibly affect the regulation of voltage in the transformer.

Addressing point b) ... this is a known problem (hence the need for ECC
memory), and is indeed the cause of many (initially) mysterious problems
with PCs which are often mis-attributed to software errors (random
lockups and crashes).

However, since (otherwise functional and properly rated) power cables
are unlikely to have any effect, one way or another, on the regulation
of voltage on a PSU transformer, then in this case a) does not lead to
b), and therefore the claim is very obviously false.

There is a special case WRT point a), which concerns RF interference on
poorly shielded cables and/or transformers lacking RF filters, which is
only relevant to analogue signals in (typically) HiFi systems, but that
has nothing to do with either voltages or purely digital transmission,
and is only usually a problem at the amplification stage (since they
further amplify the transmitted RF interference).

-- 
K.
http://slated.org

.----
| "At the time, I thought C was the most elegant language and Java
|  the most practical one. That point of view lasted for maybe two
|  weeks after initial exposure to Lisp."   ~ Constantine Vetoshev
`----

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