Multiplicity: Maximal home networking

One keyboard, one mouse, two fully-loaded computers. This is no dual-monitor setup. It's Multiplicity, brawny home networking software, and it's pretty darn cool.

Imagine a work space with three monitors standing side by side, each displaying a different work environment. E-mail and IM are pulled up on one monitor, Word processing is open on a second, and a spreadsheet graces the third. Now imagine the cursor flitting effortlessly between the screens, clicking, copying, and pasting from one to the other. One keyboard sits on the desk, and just one mouse.

This is no multimonitor setup; each screen here is controlled by its own computer. It isn't remote access software, either, since the controlling console is linked to the satellite computer. It's Multiplicity, and minus one rather large and glaring kink, it's pretty close to a multitasker's dreamware.

How Multiplicity works, in theory

You'll need: at least two networked computers, two monitors, and some patience.

The program creates a power hierarchy where the keyboard and mouse of the master computer (whichever one you select) commands operations for all computers linked on your network. More useful still, Multiplicity allows users to copy/paste text, URLs, and images from one computer to any other on the network.

Once Multiplicity is installed, the primary computer sends feelers through the network. Like a heat-seeking missile, it locks onto computers with the Multiplicity client installed on the drive and adds them as satellites. The primary PC will, in essence, remotely access the secondary, satellite PCs. Again, it's best not to think of Multiplicity as a remote desktop, since the linked computers are intended to work in concert with you, on location.

In the simplest sense, Multiplicity may be thought of as a home networking enhancer that manipulates the Windows shell. That explains the cross-monitor action. It also creates a meta-clipboard out of each computer's TCP transport hubs, which is used to copy and paste text and images between separate computers.

Opening TCP port on Norton
Opening TCP port 30564 may take some digging. (Credit: CNET Networks)

A rickety installation

Multiplicity compellingly answers the question of what to do with previous-generation technology that isn't as flashy as your new duds but not yet creaky enough for the dump heap. This scenario fits in my house, where various versions of laptops and desktops are grudgingly booted up only when the sleek, fast Vista machine is in use. For this evaluation, I put Multiplicity to the test by yoking a slower, yet perfectly functional XP desktop to our new, zippy home-brewed Vista PC.

Following the wizard's instructions, I installed the file on the secondary computer before installing it on the primary, or master, computer. This sets anchors that the control software on the master computer will detect as it sniffs for other participating machines.

Ready? Set! Choke. Implanting the executable was simple enough, but getting the computers to communicate proved to be an uphill battle that tested my patience. Multiplicity tersely notes during installation that users with third-party firewalls must manually open TCP port 30564 and also add two EXEs--MULTIPL.EXE and MULTISRV32.EXE--to the firewall's white list.

The program claims to be easy enough for novice users to set up, but the lack of further instruction leaves users to fend for themselves. As each security system has its own menus for accessing white lists and ports, it's understandable that no universal directions exist. However, most users (especially us novice networkers) will need a bigger hint.

What Stardock should have advised and didn't (not even in direct response to a user's post on the support forum) are the common procedures one might have to follow for configuring a firewall. For instance, many antivirus programs will require users to create one rule to allow inbound communication from the other IPs in the network, and create another rule to white list the EXEs.

It's also not very clear what should be done with the two executables. Stardock confirms that adding both EXEs to each computer allows users to easily appoint a new primary machine. Technically, however, users should add MULTIPL.EXE to the white list in their firewall's configuration for the primary computer, and MULTISRV32.EXE for use on satellite computers.

Adding IP address
Adding the IP address of the secondary computer to the firewall\'s \'allow\' list. (Credit: CNET Networks)

Multiplicity at work

After two tedious hours of a live chat with Norton's tech support bore fruit, my mouse was coasting from one monitor to another, copying the contents of files stored on the XP system and pasting them into the Vista computer. Just as advertised, I was successfully able to copy and paste text, images, URLS, and screenshots back and forth.

Controlling the screen borders took some getting used to--I got too close to the edge and more than once and spilled onto the monitor of the satellite computer. Numerous screen-locking and switching controls, including hot-key preferences, can reign in wayward mouse movements. I wasn't able to divine a hot-key combination that switched me from screen to screen, as every keystroke I tried was already mapped to another function. Other forums users reported more success.

Multiplicity Professional ($49.99, versus $29.99 for the standard edition) adds file-sharing capabilities, an extremely useful productivity boost. However, it doesn't yet support dragging and dropping files across the border. Try it and your item will repeatedly bounce against the edge of your screen.

Multiplicity's many applications

Users will find it's easy to adapt to Multiplicity's functionality. After all, who doesn't enjoy bulking up their real estate? Other desktop-maximizing solutions out there, like dual-monitor setups and virtual desktops, offer some competition, but Multiplicity flexes its muscles in expanding your computing horizon across two, three, or more monitors without bogging down the processing power or maxing out storage. It's also quicker than transporting files for yourself via the share folders on a standard network.

Gamers and graphic designers will particularly enjoy the program's features that were created with them in mind--including the switching controls mentioned above--that enable users to dedicate one computer to a full-screen game and another to other data pursuits.

It could take some time getting used to the computers' independent work flow even as the monitors cooperate (for example, my IM client remains stapled to one computer) but the ease of accessing and switching among multiple tasks is thus far unparalleled. Despite its start-up tangles, which I'm confident Stardock will iron out, Multiplicity is a worthy addition to any user's productivity optimizing collection, especially if said user has several extra computers on hand...and a coffin for now-extraneous keyboard and mice.

About Jessica Dolcourt

Jessica Dolcourt reviews smartphones and cell phones, covers handset news, and pens the monthly column Smartphones Unlocked. A senior editor, she started at CNET in 2006 and spent four years reviewing mobile and desktop software before taking on devices.