"For the developers and end-users using THEOS based applications the system benefits are readily apparent. But let's take a look under the hood and see what makes THEOS operating system and development language so unique and long-lived." (Also available as PDF download.)
"THEOS has a well-earned reputation of over 20 years of success developing a stable, low cost, virus-proof operating system with hundreds of mission critical applications used by millions of end users worldwide."
THEOS® Software Corporation
