eeprom.lua

local path = "/init.lua"

------------------------------------------------

local eeprom = component.proxy(component.list("eeprom")())
local write = function() end
local gpu = false

local function sleep(timeout)
  checkArg(1, timeout, "number", "nil")
  local deadline = computer.uptime() + (timeout or 0)
  repeat
    computer.pullSignal(deadline - computer.uptime())
  until computer.uptime() >= deadline
end

if component.list("gpu") then

  gpu = component.proxy(component.list("gpu")())

  local w, h = gpu.maxResolution()
  gpu.setResolution(w, h)

  gpu.setBackground(0xffffff)
  gpu.fill(1, 1, w, h, " ")

  write = function(text)

    local tag = "loading..."

    gpu.setBackground(0xffffff)
    gpu.setForeground(0x000000)
    gpu.set(w/2-string.len(tag)/2, h/2-1, tag)
    gpu.setForeground(0x646464)
    gpu.set(w/2-string.len(text)/2, h/2, text)

    sleep(0.5)

  end

end

write("Starting")

if not component.list("filesystem") then error("No bootable medium found") end
local fs = component.proxy(component.list("filesystem")())

local internet = false
if component.list("internet") then internet = component.proxy(component.list("internet")()) end

computer.setBootAddress = function(address)

  return eeprom.setData(address)

end

computer.getBootAddress = function()

  return eeprom.getData()

end

local function l_loadfile(path, address)

  local drive

  if address then

    drive = component.proxy(address)

  else

    drive = component.proxy(computer.getBootAddress() or component.list("filesystem")())

  end

  if not drive.exists(path) then return nil, "file does not exists" end
  if drive.isDirectory(path) then return nil, "file is directory" end

  local handle, reason = drive.open(path, "r")

  if not handle then return nil, "handle error: " .. reason end

  local code = drive.read(handle, math.huge)

  return load(code)

end

local function hex(r, g, b)

  local color
  if r>=0 and r<=255 and g>=0 and g<=255 and b>=0 and g<=255 then color = (r *(256^2)) + (g * 256) + b end
  return color or 0

end

write("Searching bootable drive")

local fss = component.list("filesystem")

local fs_address

for fs in pairs(fss) do

  local proxy = component.proxy(fs)

  if proxy.exists(path) and not proxy.isDirectory(path) then

    local handle = proxy.open(path, "r")
    local code = proxy.read(handle, math.huge)
    proxy.close(handle)

    if load(code) then fs_address = fs end

  end

end

if not fs_address then

  if gpu then

    gpu.setBackground(0x0000ff)

    local w, h = gpu.getResolution()

    gpu.fill(1, 1, 1, h, " ")

    for i = 1, w do

      gpu.copy(1, 1, w, h, 1, 0)
      sleep(0)

    end

    error("No bootable "..path.." found")

  else

    for i = 1, 3 do computer.beep(500, 0.1) end
    error("No bootable "..path.." found")

  end

else

  write("Booting from " .. fs_address)

  computer.setBootAddress(fs_address)

  for i = 255, 1, -8 do

    local w, h = gpu.getResolution()
    gpu.setBackground(hex(i, i, i))
    gpu.fill(1, 1, w, h, " ")
    sleep(0)

  end

  local func, reason = l_loadfile(path, computer.getBootAddress())

  if func then func() else error("Error with loading boot file: " .. reason) end

end