GoKawiilIBM unveils dual-ISA mainframe core supporting z/Architecture and Arm at Hot Chips 2026
IBM's next-generation mainframe processor, discussed by Christian Jacobi and Christian Zoellin at Hot Chips 2026, integrates decoders capable of handling both the z/Architecture instruction set and Arm instructions within the same core. The chip uses a shared decode pipeline with separate instruction decoders for the two architectures, a design approach IBM says differs from earlier dual-ISA attempts like Itanium.
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Combining two distinct instruction set architectures at the hardware level could let IBM's mainframes run Arm-based workloads natively alongside traditional z/Architecture software, potentially easing integration with modern cloud and enterprise ecosystems built on Arm. This is a rare and technically ambitious approach to instruction set compatibility, since previous dual-ISA efforts historically struggled to gain traction.
- IBM's new mainframe core supports both z/Architecture and Arm instruction sets natively.
- The design uses a shared decode pipeline with separate decoders for each ISA's differing instruction formats.
- The approach was detailed by IBM Fellow Christian Jacobi and core design lead Christian Zoellin at Hot Chips 2026.
Raspberry Pi 5 Single Board Computer — If IBM's dual-ISA mainframe talk got you curious about Arm silicon, the Raspberry Pi 5 is the easiest hands-on way to tinker with the Arm instruction set at home. It runs full Linux, handles containers and compiler experiments, and makes a great desktop testbed for Arm-native software.
See Raspberry Pi 5 Single Board Computer on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: chipsandcheese.com — George Cozma, 2026-08-31
Published there as: “Interviewing IBM's Christian Zoellin and Christian Jacobi”
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