There has been a lot of ill-considered press coverage about the “death” of UNIX and coverage of the wholesale migration of UNIX workloads to LINUX, some of which (the latter, not the former) I have contributed to. But to set the record straight, the extinction of UNIX is not going to happen in our lifetime.
While UNIX revenues are not growing at any major clip, it appears as if they have actually had a slight uptick over the past year, probably due to a surge by IBM, and seem to be nicely stuck around the $18 - 20B level annual range. But what is important is the “why,” not the exact dollar figure.
UNIX on proprietary RISC architectures will stay around for several reasons that primarily revolve around their being the only close alternative to mainframes in regards to specific high-end operational characteristics:
Performance – If you need the biggest single-system SMP OS image, UNIX is still the only realistic commercial alternative other than mainframes.
Isolated bulletproof partitionability – If you want to run workload on dynamically scalable and electrically isolated partitions with the option to move workloads between them while running, then UNIX is your answer.
Near-ultimate availability – If you are looking for the highest levels of reliability and availability ex mainframes and custom FT systems, UNIX is the answer. It still possesses slight availability advantages, especially if you factor in the more robust online maintenance capabilities of the leading UNIX OS variants.