Motivation
Since the 1960s computers have been shared between users. Especially in the early days of computing when computers were extremely expensive the usual paradigm was a central mainframe computer connected to numerous terminals. With the advent of personal computing this paradigm has been largely replaced by personal computers (or one computer per user).
Multiseat setups are a return to this multiuser paradigm but based around a PC which supports a number of thin clients usually consisting of a terminal per user (screen, keyboard, mouse).
In some situations a multiseat setup is more cost-effective because 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.
History
In the 1970s, it was very commonplace to connect multiple computer terminals to a single mainframe computer, even graphical terminals. Early terminals were connected with RS-232 type serial connections, either directly, or through modems. With the advent of Internet Protocol based networking, it became possible for multiple users to log into a host using telnet or – for a graphic environment – an X Window System "server". These systems would retain a physically secure "root console" for system administration and direct access to the host machine.
Support for multiple consoles in a PC running the X interface was implemented in 2001 by Miguel Freitas, using the Linux kernel and the X11 graphical system (at the time maintained by XFree86).[1] This was done using a patch in the display server to execute several instances of X at the same time such that each one captures specific mouse and keyboard events and the graphical content. This method received the name of multiseat or multiterminal.
In 2001, Thinsoft BeTwin offered a multiseat solution for Windows, utilizing multiple graphics cards and peripherals attached to a single host PC.[2]
In 2002 a Canadian company, Userful Corporation, released Userful Multiplier, a multiseat Linux software solution that enables up to 10 users to simultaneously share one computer.[3] Earlier they worked on a kernel-based approach to a multi-station platform computer, but abandoned the idea due to a problem with multiple video card support.
Other solutions appeared in 2003, such Svetoslav Slavtchev, Aivils Stoss and James Simmons worked, with the evdev and Faketty[4][5] approach modifying the Linux kernel and letting more than one user independently use the same machine. In that time, the Linux Console Project[6] also proposed an idea to use multiple independent consoles and then multiple independent keyboards and mice in a project called "Backstreet Ruby".[7] 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 C3SL team (Center for Scientific Computing and Free Software),[8] from the Federal University of Parana in Brazil, created a solution based on nested display servers, such as Xnest and Xephyr.[9] With this solution, each nested display server runs in each screen of a host display server (e.g. Xorg) and a modification to the nested servers let each one exclusively acquire its mouse and keyboard. In 2008, the C3SL group released the Multiseat Display Manager (MDM)[10] to ease the process of installation and configuration of a multiseat box. This group, also in 2008, conceived a live-CD[11] for test purposes.
In 2007, NComputing entered the market with a Windows-based multiseat product, the X-series[12] or Xtenda system, which uses a PCI add-in card to connect terminal units containing video, keyboard, mouse, and audio jacks, allowing 3 to 6 additional user seats to be added to a PC.[13] The X-series also offered Linux compatibility.[14]
In 2010, Microsoft began offering Windows MultiPoint Server, allowing one machine to host multiple users utilizing separate graphics cards and peripherals.
Automatic multiseat with USB docking stations is a feature of Fedora 17.[15][16]
Time line, commercial multiseat software evolution
- 1990, Solbourne cg30 running SunOS
- 1996–2005, Silicon Graphics InfiniteReality running Irix
- 1996, ThinSoft/BeTwin
- 1999, Ibik/ASTER
- 2001, ThinSoft BeTwin
- 2004, Open-Sense Solutions (Groovix)[17]
- 2006, NComputing X-series
- 2010, Windows MultiPoint Server
- 2011, Black Box VirtuaCore
- 2013, LISTEQ BoXedVDI[18]
