There are 7,000,000,000,000,000,000,000,000,000 atoms in a 153 pound human body.
To map the location of each atom we need 3 coordinates. To allow the body to move the coordinate matrix can be 8 feet by 8 feet by 8 feet. This box would be enough for the limbs to reach up, to the side, forward and back.
To calculate the highest number needed on the grid we will figure out how many positions are available for an atom to be located at. In real life the number would be the number of planck lengths (The smallest theoretical distance allowed in physics) so if we want to be able to measure movement similar to how we experience every day, we'll use that.
1 foot is equal to 1.885905244757553 x10^34 E34 Plank lengths or 18,859,052,447,575,530,000,000,000,000,000,000, times 8 = 150,872,420,000,000,000,000,000,000,000,000,000. That means to keep track of the location of each atom you would need and x y z coordinate each ranging from 1 - 150,872,420,000,000,000,000,000,000,000,000,000.
Each atom's location requires 115 bits of information per direction, or 345 per atom. So the total amount of memory needed to store the location of all the atoms in the human body would be 2.41500 x 10^30 bits. Divided by 8 gives us 3.01875 x 10 ^29 bytes. Divided by 10^15 gives us 3.01875 x 10^13 bytes or about 30 Trillion Petabytes.
Eric Schmidt, the CEO of Google estimated the size of the internet at only 5 million terabytes.
So what kind of computer would we need to deal with this? IBM has been able to store 1 bit of information to just 12 atoms, which means just to store one instant of an image of a human body in memory would take 1380 times as many atoms as contained in the body itself. A very rough estimate puts the weight of the memory used at 105 tons.
Can you imagine what the computing power of the Matrix movies would be to do a whole world with 5 billion plus people? You could theoretically use a compression algorithm to reduce the storage needs but that would increase the processing power needed to deal with calculating it. The interesting thing is if you did run a program like this, you could take a million years to process just 10 minutes of time for the human and to it it would seem as 10 minutes of time had passes normally.
Theoretically he would be unable to tell he was a computer program as the laws of physics would be programmed in, unless he tried to split the atom with a particle accelerator as our most basic element in this program is the atom. I don't even want to do the math to figure out how much memory it would take to store a man on a sub-atomic level. You could save a lot of processing power by not calculating the inside of inanimate objects unless they were broken.
That's an interesting thought as the uncertainty principle notes that until something is observed it could be in either outcome. It's like the universe saves processing power calculating the location of an atom until something observes it and the calculation becomes necessary.
Special thanks to David Artman for helping figure out the bit data conversions.
Sources: http://education.jlab.org/qa/mathatom_04.html
http://www.computerworld.com/s/article/9223396/IBM_smashes_Moore_s_Law_cuts_bit_size_to_12_atoms