Slot Disk Writer

local charset = {}  do -- [0-9a-zA-Z]
    for c = 48, 57  do table.insert(charset, string.char(c)) end
    for c = 65, 90  do table.insert(charset, string.char(c)) end
    for c = 97, 122 do table.insert(charset, string.char(c)) end
end

local function randomString(length)
    if not length or length <= 0 then return '' end
    math.randomseed(os.clock()^5)
    return randomString(length - 1) .. charset[math.random(1, #charset)]
end

write("Ready to receive disk...")

while true do
    turtle.suck()
    item = turtle.getItemDetail(1)

    if not item or item.name ~= "computercraft:disk" then
        turtle.drop()
    else
        turtle.dropDown()

        write("\nEnter Owner's Name: ")
        owner = read()

        diskId = disk.getID("bottom")
        diskKey = randomString(5)

        slotId = 0
        file = fs.open("slot/index", "r")

        if file then
            slotId = file.read()
            file.close()
        end
        file = fs.open("slot/index", "w")
        file.write(slotId + 1)
        file.close()

        --Write Key to Floppy
        file = fs.open("disk/keycard", "w")
        file.write(diskKey)
        file.close()
        file = fs.open("disk/slot", "w")
        file.write(slotId)
        file.close()

        --Write Key to Server
        file = fs.open("slot/"..slotId, "w")
        file.write(diskKey)

        disk.setLabel("bottom", owner.."'s Slot Key")
        write("Key Created, DiskID: "..diskId)
        disk.eject("bottom")

        os.sleep(5)
    end
end