/tmp/x0-lock 是什么东西？

moonfine

图形界面突然没了，显示器黑屏，只看到鼠标在闪，进控制台 startx，
提示
Fatal Server error

server is already active for display 0

if the server is no longer running,remove /tmp/x0-lock and start agian

我就把x0-lock 删了，再startx就出来了

这是怎么回事？删了它对以后有没有影响？

qqboy608

xauth:  creating new authority file /root/.serverauth.3489

Fatal server error:
Server is already active for display 0
        If this server is no longer running, remove /tmp/.X0-lock
        and start again.
这是怎么回事呀？