Today's menu:

(1)review last class topics

Ascii code representation is computer chracters

analog to digital voice recoginition

textbook  on ASCI and binary  system

Programming errors and their cost  Y2kspace shuttle , prescription

What is binary number? today is not necessary to use light bulb or vacuum tube to represent on/off. other means ,such as electrical currents or magnetic filds,are commonly used to represent these two states, which we call binary states

bi-2

deci-10

heti-10

we are working with decimal system(0--9)

how do you represent 10 in decimal system

9 plus 1 we don't have really  represent the result, then we have  gone through entire system once

How much 9+1 in decimal? 10

how much is 1+1 in binary system : 10   (maximum 2 )

How much is 1+7 in octal system  :10 ( maximum 8)

how much is 1+F (means 15) in hexa system  :   10(maximum 16  )       

Today we learned the science of color R G B

How many colors would you have from 000000 to ffffff, each symbol has 16 variation and think of 16*16*16*16*16*16 or 16 6 power:4096