Multiseat configuration

Main article: Time-sharing

A four-head multiterminal.

A multiseat, multi-station or multiterminal configuration is a single computer which supports multiple independent users at the same time. In modern usage the terms refer to multiple users using one personal computer, each with their own console, consisting of a keyboard a mouse, a monitor, and possibly headphones.

Motivation

With 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 a 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.

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 in to a host using telnet or – for a graphic environment – an X Window "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 Window interface was implemented in 2001 by Miguel Freitas, using the Linux operating system and the X11 graphical system (in that age maintained by XFree86).^[1] This was done using a patch in the X 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 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.^[2] 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 ^[3][4] approach modifying the kernel Linux and letting more than one user independently use the same machine. In that time, the Linux Console Project ^[5] also proposed an idea to use multiple independent consoles and then multiple independent keyboards and mice in a project called "Backstreet Ruby".^[6] 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),^[7] from Federal University of Parana in Brazil, created the solution based with nested X servers, such Xnest and Xephyr.^[8] 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. In 2008, the C3SL group releases the Multiseat Display Manager (MDM) ^[9] to ease the process of installation and configuration of a multiseat box. This group, also in 2008, conceived a live-CD ^[10] for tests purposes.

Multiseat was a planned feature for Fedora 12 but did not materialize and is currently pending.^[11]

Time line, commercial multiseat software evolution

• 1996, ThinSoft/BeTwin
• 2002, Userful Corporation
• 2004, Open-Sense Solutions (Groovix)^[12]
• 2006, NComputing
• 2006, SoftXpand
• 2010, Microsoft
• 2011, Black Box VirtuaCore
• 2011, SoftXpand 2011 Windows 7 Virtualization

Requirements

Hardware requirements

Each 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 one quad output video card (five users can be accommodated if onboard video off the motherboard is available). USB keyboards and mice are typically recommended instead of PS/2 connections, as they can be connected to a USB hub, or USB/audio hub. Additional devices and peripherals such as cameras, flash storage drives, card readers, touch screens, etc. could also be assigned to each seat. An alternative to multiple physical video cards and connections is DisplayLink over USB.

Software requirements

GNU/Linux

Userful Corporation developed Userful MultiSeat Linux, a solution that enables up to 11 users to simultaneously share one computer. It works with most of the available video cards and USB multiseat zero client devices, supports Edubuntu and other Linux distributions, and includes educational applications from the Open Source Community.^[13]

There are different solutions to set up a multiseat and others are constantly being developed. The X.Org Foundation maintains a wiki page with the latest news concerning the solutions. Currently the most pointed solutions by X.Org's wiki are the solutions using either multiple Xephyr servers over a host Xorg or run severals instances of Xorg.

The Multi-seat display manager (MDM),automseat tool helps to automatize the process of installation and configuration. Users that want to try multiseat are encouraged to try such a tool and avoid the old and hard way to set it up through these howtos (evdev, Xephyr), as stated by foundation's wiki page. On the other hand, MDM suffers from lack of updates and releases beyond the initial announcement ([1] and [2]).

Userful offers a commercially supported multiseat Linux solution called Userful Multiplier. It enables up to 10 users to simultaneously share one computer. It works with most graphics cards supported by X.Org/XFree86 as well as USB multiseat devices. It is available in 64-bit and 32-bit packages in both RPM and DEB formats, and has been tested on most major distributions, including Debian, Fedora, Mandriva Linux, SLED, SuSE and Ubuntu.^[14] A free two-user version of Userful Multiplier software for personal or trial use is available from their website.^[15]

Windows

For Windows 2000, XP and Vista operating systems, there are several commercial products to implement multiseat configurations for two or more seats.

Windows MultiPoint Server 2010 was announced on February 24, 2010. It uses Remote Desktop (Terminal Services) technologies in Windows Server 2008 R2.

Case studies

World's Largest MultiSeat Computers Deployment

On February, 2009, The Brazil Ministry of Education committed to deploy 350,000 Linux-based multiseat computing stations in more than 45,000 rural and urban schools across the country. The chosen companies to implement this project were the Canadian multiseat linux software company Userful Corporation, and its Brazilian IT partner ThinNetworks.^[16]

Paraná Digital project

One of multiterminal's successful cases is happening at Paraná Digital project. It is creating multiterminal laboratories on 2000 public schools of the state of Paraná (Brazil). More than 1.5 million users will benefit from the 40,000 terminals when the project is finished. The laboratories have four-head multiterminals running Debian. The cost of all the hardware is 50% less than the normal price, and there is absolutely no cost with software. This project developer is C3SL (Center for Scientific Computing and Free Software).

Michigan State University Research in Tanzania

Since 2008, electrical and computer engineering students from Michigan State University have installed multiterminal systems with internet access in three schools in Mto wa Mbu, Tanzania. The purpose of the project is to study the impact of having computer systems with internet access in an education system that cannot afford other educational resources such as books. The computer systems run Ubuntu 8.04 32-bit and utilize the open source Multiseat Display Manager created by C3SL. The research will eventually be used to present to government officials of third world countries in effort to showcase the positive impact of having cost-effective computing systems in schools. The project is sponsored by George and Vickie Rock and the Dow Chemical Company.^[17][18][19]

Notable installations

• Userful announced a deployment of 356,800 Linux-based virtual desktops in Brazil (February 2009)^[20]
• NComputing provided 180,000 one to one computing seats for K–12 students in the country of Macedonia^[21]

See also

• Computer multitasking
• evdev
• Dumb terminal
• faketty
• Linux Terminal Server Project
• Mainframe
• Multi-monitor
• Multiseat desktop virtualization
• Multiseat Display Manager
• Multi-user
• NComputing
• Ndiyo
• Time-sharing
• Userful
• Black Box VirtuaCore
• Windows MultiPoint
• X Window System
• X.Org Server
• Xephyr
• Xnest

References

1. ^ Multiuser PUC-RIO - Pontifícia Universidade Católica do Rio de Janeiro
2. ^ eChannel Line - Userful Upgrades Multi-Seat Linux Desktop Virtualization Solution
3. ^ Faketty LTN - SigmaNet klientu mājas lapas (Latvian)
4. ^ XFree Local Multi-User HOWTO
5. ^ Linux Console
6. ^ LTN - LATNET klientu mâjas lapas (Latvian)
7. ^ Universidade Federal do Paraná
8. ^ Multiterminal com Xephyr
9. ^ MDM Universidade Federal do Paraná (Portuguese)
10. ^ Multiterminal live-cd from C3SL/UFPR for tests
11. ^ Fedora Project
12. ^ "Open-sense Solutions". http://open-sense.com/groovix.html. Retrieved Nov 6 2010. 
13. ^ http://www2.userful.com/products/userful-multiseat-linux
14. ^ James Bannan (2007-12-29). "Turn one PC into two for free". apcmag.com. http://www.apcmag.com/turn_one_pc_into_two_for_free.htm. Retrieved 2008-05-01. 
15. ^ Compute Scotland - Desktop virtualisation boosted with Linux
16. ^ http://www.backbonemag.com/Magazine/Green_Trends_05270902.asp
17. ^ "ECE 480 Team 3 - Project Overview". msu.edu. http://www.egr.msu.edu/classes/ece480/goodman/spring10/group03/index.html. Retrieved Jun 16 2010. 
18. ^ "ECE 480 Team 4 - Project Overview". msu.edu. http://www.egr.msu.edu/classes/ece480/goodman/spring10/group04/index.htm. Retrieved Jun 16 2010. 
19. ^ "Michigan State University College of Engineering Study Abroad ICT Development in Tanzania". msu.edu. http://www.egr.msu.edu/study-abroad/programs/tanzania. Retrieved Jul 19 2010. 
20. ^ "Userful and ThinNetworks today announce that they have been selected to supply 356,800 virtualized desktops to schools in all of Brazil's 5,560 municipalities.". Userful.com. http://www.userful.com/company/linux-desktop-virtualization. Retrieved Feb 17 2008. 
21. ^ All Macedonian students to use Linux desktops