Cloudonomics: The Business Value of Cloud Computing, + Website

Updates

SaaS providers like to say that their ability to provide frequent updates is an advantage. This capability is facilitated by the SaaS model, but it’s less clear that it is of necessity a sustainable difference. In the legacy model, software updates, patches, bug fixes, and so-called service packs are made available to thousands or even millions of customers, either “pushed” on an “AutoUpdate” basis, where the update occurs automatically, or “pulled” when the user requests it. In the SaaS model, these changes are applied once (per cloud service node), and any users that subsequently access the service immediately begin using the new capability.

The advantage of this approach is application dependent. To take things to the extreme, if an application with 100 gigabytes of code were rewritten every hour in its entirety, thus requiring a complete download to each of hundreds of millions of users, the advantage of the SaaS software update model would be clear. However, if a 100-kilobyte applet is all that changes every few months and it must be distributed to a couple of hundred users, the SaaS advantage is less compelling.