Swarmstart code

--Wojbie's Swarm Miner Main Program
--This is a Top Level Overwrite that removed rednet api and coorutine from system
--Also Contains Emergency Beacon that turns of if turtle crashes and drops to shell.
--This should lessen load that turtles make on server by cutting amount of events by half
--Top Level Coorutine Overwrite Downloaded from
--http://www.computercraft.info/forums2/index.php?/topic/14785-a-smaller-top-level-coroutine-override/
--This is part of set of programs
--To get rest of them make instaler Floppy Disk by placing empty disc in disc drive and using pastebin get LXLBZK25 disk/startup

--Setting up my globals table -- Mine Table no poking!!
if not _G["wojbieGlobalsTable"] then
_G["wojbieGlobalsTable"]={}
end

-- if redner exists preform overwrite and load up beacon
if _G['rednet'] then

    local function beacon()
        local channel=15151
        local modem=false
        local pos=false
        local bep=os.startTimer(1)
        local message={["run"]=false,["id"]=os.getComputerID(),["ERROR"]=true}
        local tosend=textutils.serialize(message)
        local function transmit(...) if modem then modem.transmit(...) end end
        for _,i in pairs(redstone.getSides()) do
            if peripheral.isPresent(i) then
                if peripheral.getType(i)=="modem" then
                    modem=peripheral.wrap(i)
                        if modem["isWireless"] then
                            if modem.isWireless() then
                                modem.open(channel)
                                break
                            end
                        else
                            modem.open(channel)
                            break
                        end
                    modem=false
                end
            end
        end
        while true do
            event={os.pullEventRaw()}
            if event[1]=="timer" then
                if event[2]==bep then
                    if wojbieGlobalsTable.getTopShellRunningProgram then
                        if wojbieGlobalsTable.getTopShellRunningProgram() then
                            bep=os.startTimer(10)
                        else
                            if not message.pos then local temp temp={gps.locate(2)} message.pos={x=temp[1],y=temp[2],z=temp[3]} tosend=textutils.serialize(message) end
                            transmit(channel,1,tosend)
                            bep=os.startTimer(2)
                        end
                    else
                        bep=os.startTimer(10)
                    end
                end
            end
        end
    end

--top level overwrite start here
    --# this would also cause the shell and rednet routine to stop
    os.startTimer(0)
    coroutine.yield('timer')

    os.queueEvent("modem_message")
    local p = _G.printError
    function _G.printError()
        _G.printError = p
        _G['rednet'] = nil
        print("OK")

        local ok, err = pcall( function()
            parallel.waitForAny(function() os.run({}, "/rom/programs/shell") end,beacon)
        end )
        -- If the shell errored, let the user read it.
        if not ok then
            printError( err )
        end
        pcall( function()
            term.setCursorBlink( false )
            print( "Press any key to continue" )
            os.pullEvent( "key" )
        end )
        os.shutdown()
    end

else -- if not give beacon shell function it needs and act like normal shell startup code
    wojbieGlobalsTable.getTopShellRunningProgram = shell.getRunningProgram
    if turtle then
        shell.run("/swarminer")
    else
        shell.run("/scanner")
    end
end