2009.05_Lateral Control-Controlling Multiple Systems Simultaneously with Synergy.pdf

Controlling multiple systems simultaneously with Synergy

Lateral Control

Synergy lets you combine multiple PCs into a single virtual desktop.

By Florian Effenberger

Franck Boston, Fotolia.com

Synergy is a small but powerful tool that lets the user control multiple PCs with a single keyboard and mouse

- even across operating-system boundaries. To run Synergy, you'll need at least two PCs, each with its own

operating system, monitor, and a working network adapter. The software supports Windows from 95 through

to Vista, Mac OS X version 10.2 or newer, and Linux with the latest X server. Prebuilt packages for Windows

and Mac OS X are available from the Synergy homepage [1]. An RPM package is available for Linux and can

be installed on popular distributions, along with tools such as alien if needed. Some distributions also offer

prebuilt packages; for example, Ubuntu has a synergy package in its Universe repository.

Let's imagine a typical network administrator's workplace with a professional desktop running on Ubuntu, and

a small notebook running on Vista next to it. To remove the need to keep swapping between keyboards, the

administrator decides to install Synergy. Most of the work will be done on the desktop, the Ubuntu system. In

Synergy-speak this master system is known as the server , and the administrator will be using the keyboard

and mouse attached to it. In line with this, all other devices are clients .

Enabling Universe

Ubuntu organizes its software packages in numerous repositories. Universe is a hold-all for packages that are

not as comprehensively supported and maintained as some others. To use Universe , you first need to enable

the entry in the /etc/apt/sources.list by removing the pound sign. Then, after running apt-get update , you can

install various new packages, including Synergy.

Configuration

Before you start using Synergy, you need to configure the program by editing the /etc/synergy.conf or

~/.synergy.conf text files. The program relies on the concept of screens: Every computer in the group, no

matter whether it is a server or a client, is a screen with a precisely defined position - just like assigning

positions to applications on a multiple display setup. You must add the screen name, its aliases, and the

position relative to the other devices to the configuration file. It is important to define the position in both

directions, left and right. The setup for our case study, and comments on it, are given in Listing 1. There are

many more options, all of which are documented on the Synergy homepage [2].

A word of warning: Make sure you write all the options in the configuration file in lowercase, and pay

attention to line breaks because Synergy is finicky and will not load the file if you make a mistake. After you

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complete the setup, launch the Synergy server on Ubuntu as a normal user by typing synergys . Adding the -f

prevents Synergy running in the background as a service.

Listing 1: Case study

01 # Define screens

02 section: screens

03 ubuntu:

04 vista:

05 end

07 # Alternative names

08 section: aliases

09 # ubuntu -> desktop

10 ubuntu:

11 desktop

12 # vista -> notebook

13 vista:

14 notebook

15 end

17 # Screen positions

18 section: left

19 # vista: right of ubuntu

20 ubuntu:

21 right = vista

22 # ubuntu: left of vista

23 vista:

24 left = ubuntu

25 end

QuickSynergy

QuickSynergy gives you an even more convenient approach to configuring the tool. On Ubuntu, you can

download the QuickSynergy package from the Universe repository and install it, then launch it via

Applications | Tools | QuickSynergy . Unfortunately, the program failed to launch a working server in our lab.

The Vista client - that is, the PC we will be controlling via the Ubuntu system - is easier to configure. After

completing the install, you can launch Synergy directly via the Start menu, which takes you to a neat-looking

graphical interface (Figure 1). To connect to the server, select the Use another computer's shared keyboard

and mouse option and enter the name of the server machine. Professionals might also be interested in setting

extras, such as the logging level, autostart, and network details.

Figure 1: Synergy as a client on Windows Vista.

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Linking Screens

After configuring your clients, just type synergyc server IP (or click Start if you are working on Windows), to

connect the screens. This is all fairly unspectacular at first - you can use both systems in the normal way.

But if you move the mouse cursor over the right-hand border of the screen on the Ubuntu desktop, it shifts to

the Vista desktop, just like on a multiple display system - the difference is that you are using two operating

system platforms. Keyboard input will also reach the client while the focus is on it (i.e., the mouse cursor is

on the client screen). On top of this, Synergy synchronizes the clipboard between the two systems; according

to the developers, automatically setting the correct character set and converting line breaks between operating

systems - a perfect way of copying longer texts and configuration files centrally. Pressing Scroll disables

Synergy temporarily if needed.

There are many more options that you can set in the configuration file. Among other things, Synergy supports

keyboard mapping between the server and the clients, lets you configure screen areas where no screen paging

will take place, and lets you run certain actions with the press of a button.

Of course, nobody's perfect, and Synergy failed on a couple of counts in our lab. For example, it failed to

synchronize the screensavers and centrally lock all the screens.

According to the homepage, the Mac OS X variant of the program in particular is not as mature as the Linux

and Windows versions.

Security Note

As Synergy's authors point out on their homepage, Synergy does not possess anything in the line of

authentication or encryption [3]. To be on the safe side, you might like to set up an SSH tunnel and encrypt

all your data.

Conclusions

Synergy offers an interesting approach to centrally managing multiple computers without investing in

additional hardware. In contrast to legacy solutions, every machine keeps its own display. The program is

definitely a boon for anybody who needs to run several machines, and Synergy's cross-operating system

clipboard support is really useful feature that removes the need to copy text files. But if I had three wishes,

one of them would be easier configuration on Linux.

INFO

[1] Synergy homepage: http://synergy2.sourceforge.net

[2] Configuration options: http://synergy2.sourceforge.net/configuration.html

[3] Security notes: http://synergy2.sourceforge.net/security.html

THE AUTHOR

Florian Effenberger has been a free software evangelist for many years. He is the Co-Lead of

OpenOffice.org's international marketing project and a member of the board of OpenOffice.org Deutschland

e.V., a German NGO. His work mainly focuses on designing enterprise and school networks, and software

distribution solutions based on free software. Florian is a regular contributor to various German and English

language publications, in which he investigates, among other topics, legal issues.

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