XP Unlimited makes XP Pro a useful multiuser system

While looking into remote desktop protocol software that runs on Linux I discovered the product "XP Unlimited" that allows you to have multiple simultaneous RDP sessions with a standard XP Pro system. Yes folks this means you can finally remotely log into XP Pro without kicking off any user already using it "in person" or remotely.

This is useful because it also means if you have applications on a single machine and you need to access those when you are away from that machine you can easily do it via RDP. Of course this is a feature that Windows Server versions have long been able to utilize but who wants to pay $500 plus for a Windows Server license when all they need is perhaps one extra session? Similarly multiple graphical login sessions has long been supported by Linux (and it ancestors) via the X Windows environment but that doesn't really help you if you're a Windows only shop. Solutions from NComputing also allow hooking up multiple remote clients to a XP Pro system (up to 10) but XP Unlimited is the first solution I've seen that has a free version.

The free version of XP Unlimited is for non-commercial use (ideal for home users) and offers up to 3 simultaneous users. So if you have one user logged onto the machine at its physical keyboard and screen then you can have up to two additional users remotely via remote desktop connection. If your machine runs without any local users then you could have three remote users.

Even better is the commercial unlimited connection version of XP Unlimited is very reasonably priced at only $125 per machine it is installed on. I can't imagine many homes or small businesses where you'd need more than one license. For larger companies there is a higher priced version that does load balancing of sessions across machines and works with domain based systems. But at that point you're probably already using Windows Server so its utility is probably marginal for the additional cost.

I can see many scenarios where XP Unlimited would be useful:

1. Use by a family member when away from home (eg. at work) to easily access their regular desktop environment without disturbing someone else who might be using the computer. No more "are you done using the computer yet?" phone calls or irritating accidental kick offs by remote desktop users.
   
2. Use of specific applications, like a database app remotely where they would not normally run well over a network (in particular Access that does a lot of file io).
3. Sharing of a single XP computer between a bunch of non-Windows OS users (Linux or Mac) so they can access a few mission critical Windows only apps.
   
4. Allowing a remote user to do maintenance tasks on your machine while it is in regular use. As someone who maintains family and small biz computers it is nice to be able to connect to check backups, system logs, and such without worrying about when a machine is free or not. Sometimes you can do stuff by just looking at log files over file sharing, but usually it is easier to log on and run local apps like anti-virus and firewalls to check their status.
   
5. Fully utilizing a multiple processor or core machine. Most desktop users are not running multiple apps simultaneously, or running server apps in the background all the time, and most applications themselves (except games) are rarely designed to effectively utilize multiple processors. Therefore new systems with multicore CPUs or even multiple CPUs will find themselves significantly less than 50% CPU utilization day in and day out. What better way to utillize that computing power you purchased than let someone else share your machine?
   
6. Keeping legacy Windows systems useful as "dumb" terminals. New multicore systems can be orders of magnitude faster than a low end system purchased 5, 10 or more years ago. Yet those slow poke machines can easily run a remote desktop capable client and connect to a lickety-spit new machine to give the user the experience of having a brand new computer without any of the expense.
7. Reduce software and maintenance time costs. If you have five computers in your family that are largely used for mundane surfing and email it would be much easier to use them a single fast computer via remote desktop. Then concentrate all your firewall, maintenance and backup activities onto that machine and treat the other systems as "throw away" so if they have a problem you can just reformat the hard drive and reinstall XP (or Linux ;-) from scratch (see 8.)
   
8. Reduce the headache of multiple user logins across a network. Do you have a family or small business with multiple users and multiple computers? Does everyone want to log in as them on every computer and see their own files, and a similar desktop where ever they are? Using roaming profiles this can be done (even without Windows Server) but it is hard to set up, a pain to maintain passwords on (unless you set up a Samba server as a primary domain controller). However if you use a single central XP Pro machine with a lot of memory and multi-core CPU you can easily set up all the user specific stuff on it, and have the other computers with a single guest login, a bare minimum of additional applications and save yourself a lot of grief and money because you make all the other systems be very low end with a minimum of storage and memory.
   
9. Save money. In the above scenario you also gain because you no longer have to install and maintain additional copies of application software on all your machines. Just install Office once on your central machine and save several hundred bucks a pop. Some apps may license restrictions to prevent this usage scenario, or not be designed to have more than a single instance running on a single machine, however many don't.
10. Enhance security with fixed function logins. XP Unlimited has the ability to restrict a remote user to running a single application (or selection of applications). After login there is nothing else on the desktop and if they quit the single app they are logged out. That allows you to provide remote access to a system but restrict users from running software that might introduce a virus. E.g. give them database access but no browser (which they would run locally on their machine). That will significantly improve security on your shared machine. It is probably usable as a way to limit the applications your kids can run by setting up other machines in your household with a bare bones guest only restricted account with no internet access (with Windows firewall or router firewall restrictions). Let them remote desktop to your shared machine where you can restrict what additional apps they run and run central monitoring software.
    

Questions:

• Sounds to good to be true - is it legal? Well according to comments on Experts Exchange - yes. The author of the software has been in business for a long time, and really this is doing the exact same thing that NComputing also does, however the key seems to be the Windows XP license that specifically allows sharing of your system's resources by up to 10 computers. The thing that is illegal is installing XP on multiple machines (or on more than two CPU systems), not just sharing that XP installation over a network. XP Pro is not intended or licensed to be used as a "server" and hence it limits simultaneous network connections to the same port - this is how the multiple users restriction is enforced. So, in as much as XP Unlimited use doesn't violate the 10-users restriction in the license and is in any case restricted by XP Pro network restrictions then yes, it really is legal.
• Can I play games on a machine with XP Unlimited? Well to the extent you can play the game with a single remote desktop connection - yes. However most graphical games will either chug or not work at all over RDP, its just not designed for running video intensive apps.
• What about other graphical apps? If your network connection is fast you should be able use many apps that include 2D graphics, say photoshop or photo managers, but it wont be like sitting in front of the computer. Browsing the web, editing files (especially text) should work well enough - probably close to the real thing.
• What about audio? Remote desktop will pipe audio across a network but at lower quality - it is good enough for casual listening but not hi-fi. I've had a few problems with getting multiple copies of Windows media player running, but it could be because I have Napster installed and its DRM restrictions are causing problems. Other media player apps seem happy to run though.
  
• Do I need lots more memory? It mostly depends on what applications you run and how much you can put up with swapping if physical memory is exhausted. For example Internet Explorer, Photoshop, and other apps can easily start to eat up several hundred MB of memory, so if you have a couple of large apps like that running you may soon start to exceed available physical memory on even a 1GB system. But note that adding a user with XP Unlimited is unlikely to double memory use because most of the system memory usage will stay about the same with only a modest increase per user. So if you have 500MB physical memory with 400MB used and 100MB free and then another user logs in you're unlike to bump to 800Mb used, more like 500 or 600 MB. This is unlike if you used VMWare and ran multiple VMs. And remember, if memory is the only problem then adding an extra 1GB is usually quite cheap, perhaps as little as $50, certainly much cheaper than an new machine or an additional XP Pro license. Similarly it becomes easier to justify spending $100 or $200 extra for a faster or more-cored CPU when buying a new computer if it will let you double or triple the utilization of the machine.
• Yes, but does it work? Well so far after a few days of testing I'm very happy with it, even in demo mode. The only glitch I've seen was trying to run multiple Windows Media Player instances but that's not really important to me, and I think just a limitation of Napster DRM. I'm now seriously considering recommending some of my small business clients purchase it. These are people with a half dozen users or so who haven't got Windows Server and have employees traveling on the road or between offices with laptops. I think the $125 can bring them a lot of utility and make my life as a system maintainer a lot easier.