Skip to comments.The Most Awesome, Least-Advertised Fedora 17 Feature
Posted on 05/07/2012 11:20:58 AM PDT by Halfmanhalfamazing
There's one feature In the upcoming Fedora 17 release that is immensly useful but very little known, since its feature page 'ckremoval' does not explicitly refer to it in its name: true automatic multi-seat support for Linux.
A multi-seat computer is a system that offers not only one local seat for a user, but multiple, at the same time. A seat refers to a combination of a screen, a set of input devices (such as mice and keyboards), and maybe an audio card or webcam, as individual local workplace for a user. A multi-seat computer can drive an entire class room of seats with only a fraction of the cost in hardware, energy, administration and space: you only have one PC, which usually has way enough CPU power to drive 10 or more workplaces. (In fact, even a Netbook has fast enough to drive a couple of seats!) Automatic multi-seat refers to an entirely automatically managed seat setup: whenever a new seat is plugged in a new login screen immediately appears -- without any manual configuration --, and when the seat is unplugged all user sessions on it are removed without delay.
In Fedora 17 we added this functionality to the low-level user and device tracking of systemd, replacing the previous ConsoleKit logic that lacked support for automatic multi-seat. With all the ground work done in systemd, udev and the other components of our plumbing layer the last remaining bits were surprisingly easy to add.
Currently, the automatic multi-seat logic works best with the USB multi-seat hardware from Plugable you can buy cheaply on Amazon (US). These devices require exactly zero configuration with the new scheme implemented in Fedora 17: just plug them in at any time, login screens pop up on them, and you have your additional seats. Alternatively you can also assemble your seat manually with a few easy loginctl attach commands, from any kind of hardware you might have lying around. To get a full seat you need multiple graphics cards, keyboards and mice: one set for each seat. (Later on we'll probably have a graphical setup utility for additional seats, but that's not a pressing issue we believe, as the plug-n-play multi-seat support with the Plugable devices is so awesomely nice.)
Plugable provided us for free with hardware for testing multi-seat. They are also involved with the upstream development of the USB DisplayLink driver for Linux. Due to their positive involvement with Linux we can only recommend to buy their hardware. They are good guys, and support Free Software the way all hardware vendors should! (And besides that, their hardware is also nicely put together. For example, in contrast to most similar vendors they actually assign proper vendor/product IDs to their USB hardware so that we can easily recognize their hardware when plugged in to set up automatic seats.)
Currently, all this magic is only implemented in the GNOME stack with the biggest component getting updated being the GNOME Display Manager. On the Plugable USB hardware you get a full GNOME Shell session with all the usual graphical gimmicks, the same way as on any other hardware. (Yes, GNOME 3 works perfectly fine on simpler graphics cards such as these USB devices!) If you are hacking on a different desktop environment, or on a different display manager, please have a look at the multi-seat documentation we put together, and particularly at our short piece about writing display managers which are multi-seat capable.
What do it mean?
Sounds like a somewhat simpler version of the multi-user Unix systems I was building at my job 20 years ago. They had one PC (usually a then-current 386/20) with special multi-user serial cards that supported 4 or 8 terminals, and ran SCO Unix.
So this is basically thin-client/server?
This is great news!
I clicked on this thread expecting to see some new hat styles—LOL!
Plugable DC-125 USB 2.0 Laptop Docking Station and Multiseat Thin Client - VGA up to 1440x900 / 1280x1024, Audio, 2 USB ports. $64.95 @ Amazon
It’s actually better than a thin client, since you don’t have any firmware, ROM, or processing power at the seat. It acts like a KVM extender, from what I can tell.
I wonder if this would work with PS3
“A seat refers to a combination of a screen, a set of input devices (such as mice and keyboards), and maybe an audio card or webcam, as individual local workplace for a user.”
40 years ago terminals were “work stations”- now they’re “seats”.
Less theatening I guess- or just ‘truer’.
OMG, you mean Dad could get rid of the 25 computers we have sucking electricity in our house??????
I scarcely understood a word of that. I thought I was going to read about a hat that could direct my car gps-style or play cds as I walked.
I remember those days. We would install a 16 or 32 port serial multiplexor and hang dumb terminals off of them. SCO called it “Instant Mainframe”
Those where the days!
From what I've been reading about LTSP, this isn't quite the same. Sounds to me like you're just plugging keyboards, mice, and monitors into one box. However, I think the two would complement each other quite well. Rather than having to build and configure individual thin clients, if you had a setup like these for the clients, each client workstation could service multiple users. For a classroom setting, that would be kind of cool.
Yeah, pretty much. Pick the fastest of the bunch and have everybody use the one computer.
That could be a logistical problem, so one computer per room perhaps. Would still save you a ton of money, and space too.
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