Intel's Itanium lineup of 64-bit processors was an attempt at making non-x86 designs that were meant for server and enterprise workloads. As of July 29th, Intel has shipped its last batch of Itanium processors to customers and thus ended the era of this processor family.
Intel Itanium is a 64-bit processor family based on IA-64 Instruction Set Architecture (ISA). In a joint venture with Hewlett-Packard (HP), Intel decided to develop a new type of processor that would better suit the modern workloads and implement some new ideas in the processor architecture realm.
Itanium-based systems were pushed heavily by the enterprise branch of HP, called Hewlett-Packard Enterprise (HPE), which produced many server systems that contained Itanium processors. HPE called its Itanium-based systems "Integrity". Several other vendors have been involved in the production of Itanium-based systems as well, but HP was the primary driver of the platform growth.
HP even developed its own special HP-UX operating system (OS) based on Unix System V. This OS was used to power HPE Integrity servers running Itanium processors and PA-RISC instruction set architecture, which was also highly specialized ISA exclusive to HP.
IA-64 processors promised more efficiency because they lacked the massive legacy software support that x86 processors carry. Being a Very Long Instruction Word (VLIW) architecture, the Itanium architecture relies on a software compiler to calculate in advance which instructions can be executed in parallel, so the processor doesn't waste instruction cycles.
In theory, this would work well, but, in practice it resulted in limited software support for everyday server workloads, due to the need for special compilers. HP's own HP-UX OS support is ending with the Integrity servers based on Itanium processors, which are supposed to be supported until December 31st, 2025. On that date, the latest version of HP-UX, 11i v3 (B.11.31), will be at the end of life.
As the processor family has made its last shipments this year, just a few days ago, we are witnessing the end of an era that lasted for over 20 years. Itanium launched in July 2001, and the latest version called Itanium 9700 "Kittson" has made its final destination on July 29th, when Intel decided to stop any further shipment of the Itanium generation. This marks an era where, currently, Intel is using only the x86-64 architecture in its server processors going forward.