function tty(gA,sA,sI,mx,my)
 spawn("fastty: "..gA:sub(1,8)..","..sA:sub(1,8)..","..sI,function()
--  _G.nlog = ""
  local sb,lb = {},{}
  local cx, cy = 1, 1
  local sI = sI or os.getenv("sI")
  local gpu = component.proxy(gA)
  gpu.bind(sA)
  local sx, sy = gpu.maxResolution()
  sx, sy = mx or sx, my or sy

  local function wl(s)
   s=tostring(s) or ""
   for c in s:gmatch(".") do
    if c == "\f" then
     for i = 1, sy do
      sb[i] = nil
     end
     cx,cy=1,1
    elseif c == "\n" then
     cx,cy=1,cy+1
    elseif c == "\t" then
     repeat
      cx=cx+1
     until cx%8 == 0
    elseif c == "\127" then
     cx=cx-1
     if cx<1 then cx=1 end
     --(" "):rep(2)
     sb[cy] = sb[cy]:sub(1,cx-1).." "..sb[cy]:sub(cx+2)
    else
     sb[cy] = sb[cy] or ""
     while cx > sb[cy]:len() do
      sb[cy]=sb[cy] .. " "
     end
     sb[cy] = sb[cy]:sub(1,cx-1)..c..sb[cy]:sub(cx)
     if sb[cy]:len() > sx then
      sb[cy] = sb[cy]:sub(1,sx)
     end
     cx=cx+1
    end
   end
  end
  local function rd()
   while #sb > sy do
    table.remove(sb,1)
    cy=cy-1
   end
   for i = 1, sy do
    if sb[i] and sb[i] ~= lb[i] then
     if not sb[i] then
      lb[i] = nil
     else
      --lb[i] = sb[i]
     end
     local cs = sb[i]
     --nlog = nlog .. tostring(i) .. " " .. tostring(cs) .. "\n"
     while cs:len() < sx do
      cs=cs.." "
     end
     gpu.set(1,i,cs)
    end
   end
  end
  while true do
   _,si,str = event.pull("display")
   if si == sI then
    wl(str)
    rd()
   end
  end
 end,{sI=sI})
end