One of the services we offer is data migration: when you buy a new computer, we can take the data from your old system and transfer it to your new one. This migration copies your documents, music, movies, and applications, so when you turn on your new system, it’s the same as your previous one. Most of the time when we do this migration, the old system is no longer going to be used, but occasionally we are asked “Can I keep using the same applications on both systems?” There’s no simple answer to that.
Pretty much any application you install has a EULA—End User License Agreement. This is that mile-long wall of text followed by a checkbox that says “I have read and agree to the licensing terms;” in reality, no one actually READS all that fine print. What it says, basically, is that you will follow the laws governing software licensing, and the software company can revoke your right to use the application if you don’t follow the terms of the agreement. Sounds draconian, but you may be surprised to learn that when you buy software, what you’re really paying for are the rights to use that software.
One of the more important bits of information in the licensing agreement is how many copies of that application you can make. If it’s a free program like TextWrangler, you can use that on as many systems as you like. The author isn’t charging any money for it, so there’s no limit to how many times you install it. On a program that you paid for, you need to pay attention to how many times you’re allowed to install it.
The Snow Leopard upgrade disc comes as either Single User that allows you to install it on one computer, or a Family Pack that allows up to five computers. Microsoft Office:mac 2011 also comes in different license versions, allowing one install for a Single User, two installs on the Home and Business Family Pack, or three installs on the Home and Student Family Pack.
The question then becomes, “what’s to stop me from using it on more than one computer?” The first and most obvious thing would be the license key that comes with the software—originally, there wasn’t anything to stop someone from taking the install disc and putting it on every system they have. Software companies knew this was going on, and decided to switch to online registration.
When you enter the license key, a snapshot of your system is sent to the company. If you register the software on another computer, the snapshot won’t match the one on file, so you may get a message that the software has already been registered. In the case of some Microsoft products such as the Windows operating system, continued use of a duplicate software license key can cause both copies to stop working until a legal license key is entered.
Conversely, Mac OS X does not require a license key (although OS X Server does have a code to activate it). While some Apple productivity software requires a license key to install (Final Cut Pro, Aperture, etc.), apps like iWork and iLife use the honor system. The only thing stopping you from using your Single-User Snow Leopard update disc on more than one system is your own integrity. (The pressure is off with Lion though—Apple is putting it on the App Store, and has said they don’t care how many systems you upgrade with it.)
So why is all this necessary? Why can’t you just buy one copy and use it multiple times? As with most things, it boils down to money. The company that wrote it invested hundreds of hours, paying a team of developers to get it onto the shelves, and they deserve compensation for their efforts. For companies to continue putting out software, they need money.
One person might think that the difference between one or three copies isn’t going to make a lot of difference, but if everyone did the same thing, there might not be another version next year. Plus, it is technically illegal to violate license agreements. Many small businesses have been audited for compliance, and initially thought it would be cheaper to use one copy on multiple workstations. Turns out, compared to the fines they ended up paying, it would have been cheaper to just purchase the additional licenses.
If you really don’t want to pay for multiple copies of a program, an alternative would be to stick to Open Source software that doesn’t cost anything. Places like SourceForge are home to a lot of developers that do not charge for their products (although many ask for a donation so they can continue to support their software.) Another good place to look is MacUpdate, which lists free as well as paid software.