8th bit .. bit line number 8. Computer Archetecture

partyshoes · #1 $Old$ October 30th, 2009, 01:46 PM

Does anyone know what is meant by the eighth bit line 'counts up to' or 'relates to' 255 in decimal? How do bits hold information, either a 0 or a 1 so powers of 2, but if the eighth line is 2 to the power of 7 then why is it up to but not including 256.

earboth · #2 $Old$ October 30th, 2009, 03:35 PM

Quote:

Originally Posted by partyshoes $View Post$

Does anyone know what is meant by the eighth bit line 'counts up to' or 'relates to' 255 in decimal? How do bits hold information, either a 0 or a 1 so powers of 2, but if the eighth line is 2 to the power of 7 then why is it up to but not including 256.

If all 8 bits are 1 then you get:

$\sum_{n=0}^8\left(2^n\right) = 1+2+4+8+16+32+64+128 = 255$