password = "password"
debug_char = "0"

term.clear()

function mainLoop()
while(true) do
event, driveSide = os.pullEventRaw()
if(event=="disk" and driveSide) then
path = disk.getMountPath(driveSide)
if(path) then
path = path.."/access"
file = fs.exists(path) and io.open(path, "r") or nil
end
disk.eject(driveSide)
if(file and file:read()==password) then
rs.setOutput("left", true)
sleep(3)
rs.setOutput("left", false)
end
if(file) then file:close() file = nil end
elseif(debug_char and event=="char" and driveSide==debug_char) then return("break") end
end
end

rs.setOutput("left", false)
sfile = io.open("/startup", "w")
sfile:write('shell.run("keycard")')
sfile:close()

repeat
ok, err, val = pcall(mainLoop)
if(not ok and err) then
if(err=="Terminated") then print ("Access denied.")
else
print(err)
end
end
until(ok and err=="break")