http://en.wikipedia.org/wiki/MultiseatMultiseat configurationFrom Wikipedia, the free encyclopedia (Redirected from Multiseat)
A four-head multiterminal.
A multiseat, multi-station or multiterminal configuration is a single computer which supports multiple independent users at the same time. The configuration typically consists in a set of input (e.g. keyboard and mouse) and output (e.g. monitor and headphones) devices for each user.
[edit] MotivationWith the increasing capacity of processors and memory, commodity personal computers can now perform significant numbers of tasks simultaneously without slowing down. However, using standard computer configurations, only one user is able to use the computer at a time, limiting the effectiveness of the system as it remains idle most of the time. With a multiterminal, a lot of users can share the same computer, so more of its total capacity is going to be used. For example, if someone is just using a web browser or word processor, no one else can use the computer and 90% of the system's resources may be idle - but with multiterminals, other people will be able to use the otherwise idle resources. However, if someone is using all of the system's resources (playing an resource-intensive computer game, for example) the other users will have a very slow system. Multiseats are also more cost-effective: it is not necessary to buy separate motherboards, microprocessors, RAM, hard disks and other components for each user. For example, buying one high speed CPU usually costs less than buying several slower CPUs. [edit] HistoryThe idea to connect more devices in a single PC to be shared by more users appeared in 1999. It was implemented by a brazilian called Miguel Freitas, using the Linux operating system and the X11 graphical system (in that age maintained by XFree86)[1]. The way that Freitas did was a patch in the X server to execute lot of instances of X at the same time such that each one captures specifics mouse and keyboard events and the graphical content. This method received the name of multiseat or multiterminal. After Freitas, other solutions appeared in 2003, such Svetoslav Slavtchev, Aivils Stoss and James Simmons worked, with the evdev and faketty [2] [3] approach modifying the kernel Linux and letting more than one user independently use the same machine. In that time, the Linux Console Project [4] also proposed an idea to use multiple independent consoles and then multiple independent keyboards and mice in a project called "Backstreet Ruby" [5]. Backstreet Ruby is a kernel patch for the Linux kernel. It is a back port to Linux-2.4 of the Ruby kernel tree. The aim of the Linux Console developers is to enhance and reorganize the input, the console and the framebuffer subsystems in the Linux kernel, so they can work independent from each other and to allow multi-desktop operation. The Backstreet Ruby idea was never finished. In 2005, the team of C3SL (Center for Scientific Computing and Free Software), from Federal University of Parana in Brazil, created the solution based with nested X servers, such Xnest and Xephyr [6]. With this solution, each nested X server runs in each screen of a host X server (e.g. Xorg) and a modification in the nested servers let it get the exclusivity of each set of mouse and keyboard. This solutions was the most used today due its stability. In 2008, the C3SL group releases the Multiseat Display Manager (MDM) [7] to ease the process of installation and configuration of a multiseat box. This group, also in 2008, conceived a live-cd [8] for tests purposes. [edit] Howto (Linux)[edit] Hardware RequirementsEach monitor will need to be connected to a graphics output from a video card. For example, to make a four-head (four users), would require four monitors, four keyboards, four mice and two dual or four single output video cards. Additional devices such as sound boards, pendrive, headphones and etc could also be assigned to each seat. [edit] Software RequirementsThere are different solutions to set up a multiseat and others are constantly being developed. The X.Org Foundation maintains a wiki page with the last news concerning the solutions. Currently the most used and pointed by X.Org's wiki are the solutions with:
The MDM tool help to automatize the process of installation and configuration. Users that want to try multiseat are totally encouraged to try such tool and avoid the old and hard way to set up through howto (evdev, Xephyr), as stated by foundation's wiki page. |
