TurnKey Linux is built on top of 64-bit Debian Squeeze 6.0.7 Linux. The applications, which are complied from each program's newest source code rather than the Debian package management system, are being moved to 64-bit architecture.
If you want to use 32-bit apps, these are still be available from TurnKey's SourceForge site for the time being. The default architecture moving forward will be 64-bit.
Liraz Sir, TurnKey's co-founder, explained, "We'll be deprecating 32-bit support in TurnKey 13 and phasing it out completely by TurnKey 14. That means we'll be building all appliances in both 32-bit and 64-bit versions for TurnKey 13 but encouraging users to migrate to 64-bit because TurnKey 13 will most likely be the last major TurnKey release to come in both 32-bit and 64-bit image formats."
Each of these appliances can be run on a variety of server and cloud platforms, but they're designed to work on the Amazon Web Services (AWS) cloud. In the past, TurnKey apps wouldn't work on all AWS instances, but now it will work on any size instance.
While AWS is the default deployment platform, TurnKey Linux apps can be deployed in minutes on bare metal, virtual machines (VM), or in Infrastructure as a Service (IaaS) clouds.
TurnKey also has new pricing model. New users can sign up for a time-limited free trial of any TurnKey app as an AWS Micro instance. In turn, new Amazon cloud accounts automatically qualify for Amazon's free usage tier which provides up to 750 hours of Micro server usage each month for up to a year.
The hobby account has been renamed "Pay-per-use" and now comes with a $10 monthly fee. The other pricing plans, Bronze, formerly Budget; Silver; Gold and Platinum are all charged at a flat rate. If you use these services on AWS, you'll also need to pay Amazon's fees. The latter costs will vary on how much you use you your servers.
I've used TurnKey Linux server appliances myself and I've been impressed by them. They work well, the company fully supports open support, and, best of all, you really won't find an easier way to get Linux-based services up and running on the cloud.