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The book is called "Introduction to Computing Systems: From Bits and Gates to C and Beyond". Section 3.3.5 Logical Completeness. It says "We say that the set of gates {AND, OR, NOT} is logically complete because we can build a circuit to carry out the specification of any truth table we wish without using any other kind of gate. That is, the set of gates {AND, OR, and NOT} is logically complete because a barrel of AND gates, a barrel of OR gates, and a barrel of NOT gates are sufficient to build a logic circuit that carries out the specification of any desired truth table". I just want to know the meaning of the word "barrel" in this context.

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    It seems you forgot to actually include the context. Or is this all the context that you have. Then the question is plain unanswerable.
    – RegDwigнt
    Jul 16 '19 at 13:51
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    It simply means "a large quantity".
    – Hot Licks
    Jul 16 '19 at 17:31
  • Knowing that a "barrel" of such gates is not a term from boolean algebra, I read the text referenced in the OP. The reader is lead to look for some mathematical term "barrel", where as all the author means is an arbitrary "box" of AND-gates, say. In other words, a English Usage issue and not a Mathematics issue.
    – fundagain
    Jul 16 '19 at 18:45
  • It literally means a barrel. You can't build a truth table if you have [a barrel / any number of] AND gates, i.e., just AND gates will get you where you need to go, no matter how many you have, even if you have enough to fill a whole big barrel. You can build the truth table if you have a NAND gate, btw, which probably comes up next in the book.
    – jimm101
    Jul 17 '19 at 1:28
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It's difficult to be sure because the example is not a complete sentence. It probably means something like "a large supply in no particular order or arrangement" in the manner of what you might get if you tossed a bunch of stuff into a large container like a barrel.

When I was a kid I had a game called "Barrel of Monkeys." The idea is that the plastic monkeys would be in there in any old arrangement, jumbled and tangled, and you had to lift them out by using a monkey to hook on to the next one. Then the next, and so on.

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In this case, a barrel of logic gates seems to refer to an arbitrarily large supply of them, from which you are required to construct all possible logic circuits. It's a standard problem in logic circuits. What is the minimum set of gate types you need to be able to construct any possible logic circuit?

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  • I can speculate, too. I can even speculate that I can speculate much better than you.
    – RegDwigнt
    Jul 16 '19 at 13:52
  • +1 I have read the original text referred to and this is precisely the context.
    – fundagain
    Jul 16 '19 at 18:42

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