What Is I586 in Linux?

The suffix i586 is most commonly seen in binary packages (such as RPM packages) intended for installation on a Linux system.

The reference means that the package was designed for microcomputers compatible with the Intel Pentium class of processors. The Pentium line (including the Pentium MMX) succeeded the wildly successful 80486 and 80366 processors that Intel introduced in the 1980s and early 1990s.

Originally slated as the 80586 chip line, Intel later renamed them Pentiums after a court ruled that it couldn't trademark numbers. However, some computers report Pentiums as having a "586" architecture nonetheless.

There's technically a 686, too—the sixth-generation x86 line of Pentium II, Pentium III, Xeon, and Celeron chips. They're the last of the major Intel chip lines to focus on 32-bit architecture. There's no 786; after the 686 line, Intel moved to 64-bit architecture and a different naming-and-numbering scheme.

Packages for this class of machine run on later x86 based systems but there is no guarantee that they will run on i386 class machines if there have been too many processor-based optimizations implemented by the developer.