os.pullEvent = os.pullEventRaw
while true do
    term.clear()
    term.setCursorPos(1,1)
    write("Checking for keycard.\n")
    sleep(2)

    if fs.isDir("disk") then
        write("Keycard found, checking for access.\n")
        sleep(2)
        if fs.exists("disk/xiaccess") then
            h = fs.open("disk/xiaccess", "r")
            access = h.readAll()
            if tonumber(access)>1 then
                write("Access granted!\n")
                disk.eject("bottom")
                redstone.setOutput("left", true)
                sleep(3)
                redstone.setOutput("left", false)
            else
                write("Access denied! Retrying..\n")
                sleep(2)
            end
        else
            write("Keycard invalid! Retrying..\n")
            sleep(2)
        end
    else
        write("No keycard! Retrying..\n")
        sleep(2)
    end
end