PLOTTING ON MAC HELP NEEDED

Hi everyone i know there isnot too much help on plotting on MAc but i will still try. I stumbled on some information regaurding plotting on MAc and i am stuck at this stage:
Code
./plot k 6891xxx9176xxx3xxx d /Volumes/ArchiveRB/plots s 0 n 409600 m 8192 x 2 t 3I am stuck becuase i dont understand this part: n 380928 # Each nonce = 256KB. Divide (disk size) by (262144), then divide by (stagger size m) : round down, multiply by (stagger size.)
i currently want to plott 4.7 terabytes can anyone help with this conversion please

Number of nonces = floor(( disk size in bytes / 262144) / stagger) * stagger
Floor() rounds a real number down to the next lowest integer  eg floor(3.5) > 3

ok i need to know if am on the right track here i have 4.7 TB in bytes this is 4.7E+12 which is the same as 14.71828182845905...then i divide that by
262144 will give me 0.00005614578945 then divide by "stagger" and multiple by Stagger ...dont know what the stagger is. Is it the memory size??

@bere No, you need to go to the properties of the drive and get the EXACT number of bytes. Different drives from different manufactures vary in how close to X TB they are  you need the exact value for your drive.
Your drive will be somewhere around 5,000,000,000,000 bytes  you need the exact value, then divide by 262144 which gives around 19073486.328125 nonces. Divide that by stagger, ( the m value), so 19073486.328125 / 8192 = 2328.3064365386962890625, floor() that to get 2328. Multiply that by the stagger again, 2328 * 8192 = 19,070,976 Nonces.
Repeat that calculation with your exact drive size.

my word.....i dont belive this..lol...mac developers please create a graphical user interface for plotting..this is crazy...But thank you anyways you were a great help...which i had some burst would give u a few..but as you can see am just trying to plot my drives...thank you much