Big Ideas, Little knowledge. Advice/Help - ComputerCraft Forums (archive)

Posted 23 September 2014 - 09:29 PM

Well you'd want to check out fs for writing to a file, and also the disk API for ejecting the disk

Examples

Writing to a file


-- This opens the file "disk/foo" in write mode
local f = fs.open( "disk/foo", "w" )
-- this writes "bar" and then starts on a new line in the file
f.writeLine( "bar" )
-- this closes the file, it's always important to close the file after you're done reading/writing from/to it
f.close()

Ejecting a disk


disk.eject( "left" ) -- this will eject a disk on the left side of the computer

I left a link below to the wiki, you can check out os.pullEvent there.
Now onto how you could do what you explained


while true do
    local e = { os.pullEvent( "disk" ) } -- wait for a "disk" event
    local path = disk.getMountPath( e[2] ) -- get the path of the disk
    local f = fs.open( path .. "/foo", "w" ) -- open a file called "foo" on the disk
    f.writeLine( "bar" ) -- write "bar" to the disk
    f.close() -- close the file
    disk.eject( e[2] ) -- eject the disk
end

Now since you're new to ComputerCraft and Lua I would suggest that you'd first go and check out the PIL and then the wiki of ComputerCraft, starting with making a bank system as the first program isn't that easy( you're new to CC right? ), or well.. it depends. Yes you can make a bank system, but if you're new to programming the quality and security of the program might not be so good. If you're seriously thinking of creating this then I would strongly suggest that you'd hash + salt the data before storing it into a file, and have like a "server computer" that would store the data.