Itanium

Itanium is a family of 64-bit central processing units designed by Intel in collaboration with Hewlett-Packard. It was built around IA-64, an Explicitly Parallel Instruction Computing (EPIC) architecture that aimed to extract high levels of instruction-level parallelism by relying on sophisticated compilers to schedule instructions for wide instruction words and to expose parallelism across multiple instructions per cycle. The approach emphasized predication, branch prediction, and very long instruction words to improve throughput on parallel workloads.

The first generation, codenamed Merced, arrived in the early 2000s, followed by Itanium 2 (with generations such as McKinley and Montecito) and later members of the Itanium 9000 family. Itanium processors were primarily targeted at enterprise servers and workstations. Systems based on Itanium typically ran HP-UX, and later servers from HP Integrity, as well as some Linux distributions and Windows variants that supported IA-64. These machines were used in fields such as databases, e-commerce, high-performance computing, and other enterprise deployments.

Market reception and decline: Itanium faced intense competition from x86-64 processors (AMD64 and Intel 64), which provided 64-bit capabilities within the more widespread x86 ecosystem and a rapidly expanding software base. The software ecosystem, tooling, and ecosystem support for IA-64 did not grow as the ecosystem around x86-64 did, limiting overall adoption. As a result, Itanium gained only a niche position in the server market, and Intel and its partners gradually discontinued new designs and broader support for the platform.

Legacy: Itanium contributed to discussions around parallelism, compilers, and EPIC concepts, but its practical impact was limited by market dynamics. After years of limited growth, the line was phased out in favor of x86-64-based servers and other architectures in most mainstream enterprise deployments.