Computer Architecture = Instruction Set Architecture (ISA) = Processor Architecture

At its lowest level, software must execute code properly on the processor chip itself. Processor architecture is standardized to allow for code to be written and compiled that works across many individual models of chips. Some common architectures with examples are:

IA-32

IA-32 is the 32-bit version of Intel’s x86 architecture.*

*Notice x86** does not by itself specify an architecture, it is a family of Intel architecture that includes everything from 16-bit released in 1978 to modern 64-bit.

**Note, the x86 Wikipedia article has a good explanation of which chips generally use which ISA.

• The Intel 80386 microprocessor released in 1985 was the first commercial 32-bit processor.

X86-64 = X64 = X86_64 = AMD64 = INTEL 64

Released by Intel in 2003, 64-bit began to replace 32-bit.

• Intel Pentium 4 F series.

ARMV8-A

ARMv8-A is the first 64-bit version of the ARM architecture. ARMv8-A is AArch64, which is the same as ARM64.

ARM is a double-acronym. RISC stands for Reduced Instruction Set Computing. All together, ARM stands for “Advanced Reduced Instruction Set Computing Machine.” The ARM architecture in general is maintained by ARM Ltd. in Cambridge, UK.

• The ARM Cortex-A53 in the Raspberry Pi Zero 2 W uses ARMv8-A and is considered 64-bit.

Operating Systems Classified by ISA

Raspberry Pi OS

Currently, Raspberry Pi does not offer a 64-bit OS, but a beta 64-bit OS is in work and already available for download from the official library.

In a Linux command terminal, you can see processor information including architecture with the command:

lscpu

From Windows PowerShell, you can see processor information including architecture with the command:

systeminfo

Get-WmiObject Win32_Processor