Using RLM keywords “HOLD=” and “MIN_CHECKOUT=”

Many valuable software tools that require floating licensing run for only a short time.  These include various solvers, development and design tools, and other specialty software products that are designed to perform very specific tasks very quickly.  Unlike typical interactive or desktop applications, these short-burst applications typically do not have a GUI of there own, and are often launched by other applications within a product suite.

The “Short Duration” Licensing Challenge
The licensing challenge for these applications is based on the fact that a floating license is a shared license.  When a floating license is used it is unavailable until it is returned.  But, short duration tools consume licenses for only a short time, so a single license could potentially be shared by a large number of users.

The “Short Duration” Pricing Challenge
The licensing challenge is really a pricing challenge.  In other words, how do you set a price for a single floating license that is low enough for small sites to afford while at the same time scaling your pricing so that larger sites that use more of your software pay you more for that use?  How do you prevent large sites from satisfying their requirements by licensing only a single floating copy of your software?

Extra Hold Time: HOLD=
One way to handle this problem is to implement an extra “hold time” on the floating license.  This instructs the license servers to hold the license for an extra number of seconds after it is released by the client, regardless of how long the license was actually used.  So, for example, if the application uses the license for 20 seconds, upon termination of the program the license is “held” for an additional 300 seconds, say, for a total of 320 seconds.  The effect is that the floating license can be shared by fewer users because it is “held” this extra amount of  time each time it is used.  This encourages customers to order more licenses to satisfy their user population.  But, some customers may object to the license being unavailable for such a long time.

Minimum Checkout Time: MIN_CHECKOUT=
Another similar method is to enforce a “minimum” license checkout duration.  Instead of extra time being added to the end of a licensing session as in the above example, a license would be held for at least a specified minimum amount of time.  So, a license with the minimum checkout time set to 300 seconds would add 280 extra seconds to a license that was in use for only 20 seconds.  Licenses used for more than 300 seconds would not be affected.

Both “extra hold time” (HOLD=) and “minimum checkout time” (MIN_CHECKOUT=) keywords are specified in the license file, external to the application, so that the same executable can use either method without modification to the source code.