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uber basics /very offtopic/

Posted: Sat Apr 16, 2005 3:19 pm
by worker201
This isn't really about Linux, but it is about computers and smart people, which ought to be this website's subtitle.

Last night, I laid awake for hours, wondering how a computer can take the expression "49 - 7" and come up with 42. Subtraction is pretty basic, but it makes contextual sense - if I have 49 oranges and eat 7 of them, well, there you go. But a computer is not able to grasp such a concept. Being that it is nothing more than electrons moving through some sophisticated conductors, after all.

If somebody would be kind enough to explain how electronics can decide that 110001 minus 111 equals 101010, that would be great. Off-forum, if necessary.

Posted: Sat Apr 16, 2005 4:19 pm
by Tux
For a basic overview, read this.

If you want the electronics of it check out a book like The Art of Electronics: Horowitz,Hill at the university library.

Posted: Sat Apr 16, 2005 4:22 pm
by caveman
Now - I'm not so sure whether you're joking or not :lol:

But back in '75 - in varcity we had to learn the basics of computers...
way before the PC revolution..
that included the logic and circuits to do simple jobs.

So two things to have a look at - lots of them on the net with google
a) the logic and circuit of an adder (thats like in counting, not the snake)
and a half-adder.
b) the logic and circuits for and, nand, or, nor and xor gates..

That at least should put your mind to working-out how a machine uses
binary logic to get to an answer :wink:
(I saw an add on the net a while ago for training tools that included
big circuit boards with which to build the above)

a quick link...
most varcity links on electronics and computers have something similiar.. ... probc6.pdf
and a nice presentation on the above ... er04DW.ppt

Posted: Sat Apr 16, 2005 8:51 pm
by worker201
Thanks for the link, Tux. I forgot all about "how stuff works". That was a nice discussion, and it was exactly what I was looking for. I spent a whole semester as a computer science major at CU, before I ended up switching to journalism. compsci is engineering at CU, and they require calculus and Physics every semester - something I would probably not pass, and certainly not enjoy. The first course was data structures, which was just a C++ class. The second course would have been circuits, where I would have learned all this stuff.