:: Re: [DNG] F1 and special usernames …
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Autor: Didier Kryn
Data:  
Para: dng@lists.dyne.org
Assunto: Re: [DNG] F1 and special usernames on the login screen
Le 19/07/2016 16:03, Simon Hobson a écrit :
> Didier Kryn <kryn@???> wrote:
>
>>     I guess this is exactly what "multi-seat" means: severall keyboards and severall grapical cards connected to the same host. It certainly does not include serial terminals. Serial terminal fall in the category "multi-user", like ssh connections, not "multi-seat".

>
> I disagree there. In the context of "graphical consoles" being discussed I see where you are coming from, but serial terminals are just a sub class of multi-seat - while the "multiple graphics card-keyboard-mouse" setup is another sub-set. The key difference is that there is a long historyof multi-seat via serial (and more recently, network) terminals and (forexample) the serial etc systems inherently support multi-seat.
> The way the problem is solved for serial terminals is simple - abstractthe hardware into a stable device API, and run multiple instances of the"login" program (one per seat). "In theory" the same should be possible with the graphics-keybourd-mouse combo - EXCEPT that (AIUI) the software components involved were mostly written a) without that standard abstraction and b) without regard to the possibility of multiple instantiations.
> Just think how easy it musty have seemed at one point to just "intertwine" the software and hardware such that a single instance of "something" acted as the sole gatekeeper between the serial line and the machine - for a single seat. There'd then be discussions on how to work around that to enable multi-seat. As it happens, the serial line one was such a "no brainer" given how many different things used the serial lines - the solution we have must have seemed so obvious from the very beginning.
>


     I don't understand all your explanations, sorry :-) . I understood 
the concept of "seat" as the combo you describe (graphics-keyboard-mouse).


    If the concept of "seat" includes serial terminals, I see no reason 
to not include remote logins: until the middle of the 80's, serial 
terminals could be far remote, by the means of modems, and, 
conceptually, this isn't different of a telnet connection. If multi-seat 
involves all that, then the concept is not relevant in this discussion. 
Which is relevant is wether the user  can push the shutdown button of 
the DM or "send" ctrl-alt-del, and neither serial terminals, nor remote 
sessions can do that - except, possibly remote graphic sessions through 
XDMCP.


     To come back to Slim, why should it behave differently of wtfdm and 
ask a password to halt/reboot? It makes no fundamental difference wether 
this is obtained by clicking a button or by entering a special text in 
the login window.


     Didier