JBIOS

function invoke(address,method,...)
  local result = table.pack(pcall(component.invoke,address,method,...))
  if not result[1] then
    return nil,result[2]
  else
    return table.unpack(result,2,result.n)
  end
end

local cp = 1
local gpu = component.list("gpu")()
local screen = component.list("screen")()
invoke(screen,"turnOff")
invoke(screen,"turnOn")
if gpu and screen then
  invoke(gpu,"bind",screen)
end
function print(string)
 invoke(gpu,"set",1,cp,string)
 cp=cp+1
end

function loadOS(address)
  local handle = invoke(address,"open","/init.lua")
  local data = invoke(address,"read",handle,math.huge)
  invoke(address,"close,handle")
  load(data,"=init")
  init()
end








print("Loading JBIOS....")
print("Finding Bootable Devices....")
filesys = {}
c=1
for addr in component.list("filesystem")do
 filesys[c]=address-------------<<<Always empty
 print(address)--------<<<<<<<always blank
 c=c+1
end
i=1
i0=1
boots = {}
while i<11 do
  if filesys[i] then
   bool = invoke(filesys[i],"exists","/init.lua")
    if bool then
      boots[i0]=filesys[i]
      i0=i0+1
    end
  end
  i=i+1
end
print("Found: "..#boots.." Bootable Filesystems")-----------always 0
i=1
 print("Please Select Filesystem to boot from")
while boots[i] do
 label =  invoke(boots[i],"getLabel")
  print(i..": "..label)
  i=i+1
end
print("b: Boot Now")
print("Will auto boot in ten seconds if you dont select a system to boot.")
time = os.time()+11
codes = {0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0A,0x0B,0x30}
code = 0x00
while os.time()<=time do
  local ev,addr,char,code,name = computer.pullSignal(10)
  if(ev=="key_down")then
    i1=1
    if code==0x02 or code==0x03 or code==0x04 or code==0x05 or code==0x06 or code==0x07 or code==0x08 or code==0x09 or code==0x0A or code==0x0B then
      loadOS(boots[code])
      break
    elseif code==11 then
      char0=char
      break
    end
  end
end
if not computer.getBootAddress() then
  loadOS(computer.getBootAddress())
else
  loadOS(boots[1])
end