The next generation computers will likely use a 64-bit word size, and the maximum
count possible with 64 bits is something like a trillion billions!
The ability to represent a large number directly is nice, but it comes at a cost of ???bit efficiency.??? Here??™s what
the number 6 looks like in a 32-bit word:
00000000000000000000000000000110
There are a lot of wasted bits (leading zeros) there! When memory was more expensive, engineers used to
see bit-efficiency as a consideration, but memory is now so inexpensive that it usually is no longer a concern.
INTEGER DATA FORMATS
So far our discussion has been of whole numbers only, and even of positive whole numbers. Computers
need to keep track of the sign of a number, and must also be able to represent fractional values (real numbers).
As you might expect, if we need to keep track of the sign of a number, we can devote a bit of the computer
word to maintaining the sign of the number. The leftmost bit, also known as the most significant bit (???msb?????”
in contrast to the least significant bit, ???lsb,??? at the right end of the word), will be zero if the number is positive,
and 1 if the number is negative. Here is a positive 6 for an 8-bit computer:
00000110
The msb is 0, so this is a positive number, and we can inspect the remaining 7 bits and see that the value is 6.
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