VLA 3

local modem;

local totalComputers = math.ceil(65536/(128 * 5))

function master()
  local currentID = 0;
  modem = peripheral.wrap("back");
  modem.open(0);
  local computers = {peripheral.find("computer")}
  for k, v in pairs(computers) do
    v.shutdown();
    sleep(0);
    v.turnOn();
    sleep(0);
  end
  sleep(1)
  modem.transmit(0, 0, "getID");
  for i = 0, (totalComputers - 1) do
    local ev, _, _, id, msg = os.pullEvent("modem_message");
    modem.transmit(0, id, textutils.serialize(i));
    i = i + 1
    print(i .. " / " .. totalComputers .. " online. (" .. id .. ")");
  end
  print("Activating array");
  modem.transmit(0, 0, "initiate");
  while true do
    local ev, _, _, _, msg = os.pullEvent("modem_message");
    local ary = textutils.unserialize(msg);
    print(ary[0] .. " -> " .. ary[1] ..  ": " .. ary[2]);
  end
end

function openModem(mod, i, offset, mult)
  local chan = offset + (mult * 128) + i
  if chan <= 65535 then
    mod.open(chan);
  end
end

function slave()
  local globalID = nil;
  modem = peripheral.wrap("bottom");
  modem.open(0);
  os.pullEvent("modem_message");
  modem.transmit(0, os.getComputerID(), "metoothanks");
  local done = false
  while not done do
    local ev, _, _, toID, msg = os.pullEvent("modem_message");
    if toID == os.getComputerID() then
      done = true
      globalID = textutils.unserialize(msg);
      print("Global ID: " .. globalID)
    end
  end
  local done = false
  while not done do
    local ev, _, _, toID, msg = os.pullEvent("modem_message");
    if msg == "initiate" then
      done = true
      local modem1 = peripheral.wrap("top");
      local modem2 = peripheral.wrap("left");
      local modem3 = peripheral.wrap("right");
      local modem4 = peripheral.wrap("front");
      local modem5 = peripheral.wrap("back");
      local offset = globalID * (128 * 5)
      for i = 0, 127 do
        openModem(modem1, i, offset, 0);
        openModem(modem2, i, offset, 1);
        openModem(modem3, i, offset, 2);
        openModem(modem4, i, offset, 3);
        openModem(modem5, i, offset, 4);
      end
    end
  end

  while true do
    local ev, side, sender, reply, msg = os.pullEvent("modem_message");
    if side ~= "bottom" then
      local data = {reply, sender, msg}
      modem.transmit(0, 0, textutils.serialize(data))
    end
  end
end

if fs.exists("/master") then
  master();
else
  slave();
end