ISO/IEC 23360-8-2:2021

ISO/IEC 23360-8-2:2021 - Overview

ISO/IEC 23360-8-2:2021 is the S390X architecture–specific part of the Linux Standard Base (LSB) Core specification. Published in 2021, it supplements the LSB Core - Generic document with the processor- and ABI-specific details required for compiled applications targeting IBM z/Architecture 64-bit (s390x). The standard defines a uniform system interface and a minimal installation environment to enable binary portability and predictable behavior of high-volume Linux applications on s390x platforms.

Key topics and technical requirements

This document focuses on binary-level compatibility and contains mandatory interface definitions except where explicitly noted. Key technical topics include:

• Application Binary Interface (ABI) and Application Programming Interface (API) distinctions - LSB is primarily a binary (ABI) specification while referencing source-level APIs.
• Executable and Linking Format (ELF) - object formats, ELF headers, sections, symbol tables and relocation specifics for s390x.
• Low-level machine interface - calling conventions, machine-specific registers and process initialization behaviors relevant to s390x.
• Program loading and dynamic linking - program interpreter/dynamic linker behavior and expectations for run-time linking on s390x.
• Base and utility libraries required by LSB Core (examples listed in the specification): libc, libm, libpthread, libgcc_s, libdl, libcrypt, libz, libncurses, libstdc++, etc., with data definitions and interface requirements for s390x.
• Package format and installation considerations - package dependencies and architecture considerations to support predictable installation scripts.
• Conformance and versioning - implementation and application conformance rules; recommendations such as symbol versioning to support backwards compatibility.

Practical applications and typical users

Who benefits from ISO/IEC 23360-8-2:2021:

• Linux distribution maintainers and OS vendors - implement LSB-conforming system images on s390x to support portable binaries.
• Application and package maintainers - build and certify high-volume commercial or open-source binaries that run reliably on s390x.
• Compiler and toolchain developers - ensure generated code follows s390x calling conventions, ELF semantics, and ABI expectations.
• System integrators and QA teams - validate runtime behavior, dynamic linking, and library compatibility on s390x hardware.
• Independent software vendors (ISVs) - reduce porting effort and support a single binary distribution across certified s390x systems.

Practical benefits include improved binary portability, predictable runtime linking, standardized library behavior, and reduced fragmentation for s390x Linux deployments.

Related standards

• LSB Core - Generic (use in conjunction with this part)
• Other parts of ISO/IEC 23360 series covering additional architectures and modules
• External references for POSIX and standard C library semantics (as cited in the LSB Core documents)

Keywords: Linux Standard Base, LSB, ISO/IEC 23360-8-2:2021, S390X, s390x ABI, application binary interface, ELF, libc, dynamic linker, package installation, binary portability.