[aklug] Re: [OT] Re: random bits vs random Hex

All,

        I believe the horse is now dead! I would like to extend a thank you
to all who provided such rich and thought provoking responses to my post! I
am both grateful and somewhat humbled by the knowledge base displayed thru
this thread. For my own part I learned several new things and some new ways
to consider the issues which led to the question to begin with. In the end
based on both the majority of your input as well as my own additional
research I believe the 'Bard' summed it up quite well in "Romeo and Juliet"
Act II Scene II in which Juliet argues that the names of things do not
matter, only what things "are". Or, more simply, "A rose by any other name
would smell as sweet".

Best regards,
Dan

-----Original Message-----
From: aklug-bounce@aklug.org [mailto:aklug-bounce@aklug.org] On Behalf Of
Arthur Corliss
Sent: Wednesday, May 29, 2013 3:51 PM
To: Doug Davey
Cc: aklug@aklug.org
Subject: [aklug] Re: [OT] Re: random bits vs random Hex

On Wed, 29 May 2013, Doug Davey wrote:

> The point is that we are discussing how compression works, how binary
> is displayed, and also bringing up some common mistakes when storing
> binary values. Namely storing it in a silly format. Typical data
> storage schemes for files will have unused space, and heavily repeated
> patterns, which make compression worthwhile. Random strings do not.
> If you make a mistake with storing your random number, and add a ton
> of space, you will see a compression algorithm work on it, and bring
> it back down in size to the actual data being represented.

I think people are likely to get themselves confused and tied up by what is
not a data issue, but a presentation issue. In order for this to have any
practical impact on the coder whatsoever said coder would have to go out of
their way to create this problem in storage, like taking a binary stream,
converting every octal value to string-encoded decimal, and storing *that*
all concatenated. I would be extremely surprised if anyone here, new coder
or not, would do something like that.

> And yes, James, sometimes you might get a random stream of bits that
> have some patterns in it that will be compressible, but that should be
> a warning sign that your stream might be less than random.

Anything truly random will be unpredictable in anticipation, but that does
not mean that a random stream is not compressable. Long enough streams will
almost certainly be, it is simply that the level of compression gained will
be low in comparison to, say, English text. Any given short sequence of
data can reoccur within a stream and as long as you can't predict in advance
*when* it will recoccur it will still be considered random.

In short, compression may be an indicator of randomness, but it is not a
guarantee. Just to clarify your point a bit.

         --Arthur Corliss
           Live Free or Die
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Received on Wed May 29 20:25:05 2013