April 23, 2018 Monday
Bedtime Story
Note B of Ada Lovelace - Part 3
Tonight it’s time to return back to Note B
from where we had left it in the night of April 01, 2018 and proceed to Part 3
of the note B.
Note B will not be a breeze as was A
because Note B is the description of the storehouse of the engine, which in
today’s parlance is called memory.
To briefly recap, the storehouse would be
series of columns of discs heaped one over the other to “a considerable height”
with each disc numbered 0 to 9 equidistantly at its circumference.
The Difference Engine would have seven of
these columns but the Analytical Engine would have “many more of these columns”.
These columns of numbered discs she labels
as Variable columns or sometimes simply as Variables with a capital “V” which
she clarifies has nothing to do with the variables and constants that are used
in mathematics.
Each column on top will have a empty circle
that can be assigned either a ‘+’ or a ‘-‘ sign thereby revealing whether the
number below it is a positive or a negative one.
The columns on the paper can be represented
as follows:
Continuation of Note B – Part 3
“The zeros beneath the symbolic circles represent
each of them a disc, supposed to have the digit 0 presented in front.”
Just to remind you, Ada Lovelace is talking
about the following diagram that she uses to represent the columns of discs of
both the Difference and the Analytical engines on paper.
“Only four tiers of zeros have been figured
in the diagram, but these may be considered as representing thirty or forty, or
any numbers of tiers of discs that may be required.
Since each disc can represent any digit,
and each circle any sign, the discs of every column may be so adjusted as to
express any positive or negative number whatever within the limits of the
machine; which limits depend on the perpendicular extent of the mechanism, that
is, on the number of discs to a column.
Each of the squares below the zeros is
intended for the inscription of any general symbol or combination of symbols we
please; it being understood that the number represented on the column
immediately above is the numerical value of that symbol, or combination of
symbols.
Let us, for instance, represent the three
quantities a, n, x, and let us further suppose that a = 5, n =7, x = 98.
We should have –
(Footnote- It is convenient to omit the
circles whenever the signs + or – can be actually represented)”
Stay tuned to the voice of an average story storytelling
chimpanzee or login at http://panarrans.blogspot.com
Good night mon ami and my fellow cousin ape.
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Another great educator and a teacher that I am aware of is
Professor Subhashish Chattopadhyay in Bangalore, India.
While I narrate stories, Professor Subhashish an electronic
engineer and a former professor at BARC, does and teaches real mathematics and
physics.
He started the participation of Indian students at the
International Physics Olympiad.
Do visit him here:
All his books can be downloaded for free through this link:
For edutainment and English education of your children, I
recommend this large collection of Halloween Songs for Kids:
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