data representation Flashcards
how do you convert from hex to denary
go through binary and then to denary, you cannot go straight through
3 reasons hex is used
easier for humans to read. uses less digits than binary. less input errors
how do you times or divide a binary number
using binary shift. shift to the left for times and to the right for divide
how would you add two binary numbers
using column addition
what is an overflow error
when adding two 8 bit numbers gives a nine bit number
what is a problem with overflow errors
it gives an incorrect calculation
how do you convert from binary to hex
“split the 8 bit binary to two 4 bit binary numbers. assign each one to a hex no then
merge the two”
what is ASCII
most commonly used character set in english speaking world
how many bits are in ASCII and how many characters can it code for
7, 128
what is extended ASCII
same as normal ASCII but codes for 256 characters, using 8 bits
what does unicode do
“it tries to cover every possible character from all languages for example. 16 or 32
bit.”
how are images stored
as a series of pixels, which are coded through binary
what is the formula to work out how many colours are stored in an image
2^no of bits
what does resolution mean
density of pixels in an image
what is analouge
pieces of continually changing data
