Intel Binary Compatibility Standard

The Intel Binary Compatibility Standard (iBCS) is a standardized application binary interface (ABI) for Unix operating systems on Intel-386-compatible computers, published by AT&T, Intel and SCO in 1988, and updated in 1990. It extends source-level standards such as POSIX and XPG3 by standardizing various operating system interfaces, including the filesystem hierarchy layout (i.e., the locations of system files and installed programs), so that Unix programs would run on the various vendor-specific Unix implementations for Intel hardware (such as Xenix, SCO Unix and System V implementations).

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