Question

Hey 1st Ques! Why only 2,4,8,16,32 bits(power of 2), make 1 byte? Why not 3,5,6,7...? I've asked this to various ppl, lets see how you answer.

Answer 1

A single byte is conventionally 8 bits long, long enough to encode ASCII characters. However, there's a little more to that...

Answer 2

1byte=8bits=2^3bits

Answer 3

There are ones and there are zeroes, 2 symbols. We can use these two and a few operations to solve just about any logical problem.
http://en.wikipedia.org/wiki/Turing_machine

You can see 1/0 as yes/no or hole/no hole. Computers used to run on perforated tape on which you could determine these two states. Why not use no hole/square hole/round hole or somesuch? Well, it's just not neccessary it seems. We like to use 10 alot, probably because we have 10 fingers. That doesn't mean it's the optimal choice. For electronics it makes much more sense to construct elements that behave in one way if there is current and in a another when there isn't to have say 7 or 10 states for different currents.

I've heard some people argue that science will never be able to simulate a brain(create artificial intelligence) using the binary system because the brain is much more complicated. I have never understood where they get this idea.

And I have drifted off, haven't I?...I was trying to explain why powers of two are so common. A byte is an agreed upon unit just like a meter or a gallon and 8-bit bytes are standard. A signed byte for example has 7 bits for a number and 1 bit for the sign (+/-).

In short it's probably more convenient to divide an arbitrary number of bits into pieces of a power of two size. For example using 3 we would probably waste some memory because a double would then be 6 bits - one is odd, the other even and so on.

Answer 4

8 bits now = 1 byte. In the 60's and 70's there were various sizes of bytes. At that time they were thinking of making a byte 6 bits. Probably how octal got into the vernacular.

16, 32 and 64 bits are word sizes.

One clarification, technically, 7 bits are all that's needed for ASCII. Extended ASCII requires 8 bits.