ubuntu 32/64 bit

https://askubuntu.com/questions/454253/how-to-run-32-bit-app-in-ubuntu-64-bit

how to run 32-bit app in Ubuntu 64-bit?

Install 32-bit basic libs, like libc6 & libstdc

https://www.howtogeek.com/198615/how-to-check-if-your-linux-system-is-32-bit-or-64-bit

How to Check if Your Linux System Is 32-bit or 64-bit

Lscpu or uname -a

The “Architecture” entry tells you what type of CPU you have (where “x86_32” signifies 32-bit and “x86_64” signifies 64-bit).

The “CPU op-mode(s)” entry tells you what version of Linux you’re running. If you’re running a 64-bit version, you’ll see both 32-bit and 64-bit modes listed (since a 64-bit processor can run both). If you only see the 32-bit mode listed, you’re running a 32-bit version of Linux.

i386对应的是32位系统、而i686是i386的一个子集,i686仅对应P6及以上级别的CPU，i386则广泛适用于80386以上的各种CPU；x86_64主要是64位系统。

https://askubuntu.com/questions/3378/my-processor-is-64-bit-does-that-mean-i-need-the-amd64-image?rq=1

There is a processor type called IA-64 or Itanium. It's only found in supercomputers and a few high-end servers.

X64, amd64 and x86-64 are names for the same processor type. It's often called amd64 because AMD came up with it initially. All current general-public 64-bit desktops and servers have an amd64 processor.

Linnux-x86 |  linux-x64 linux-x86_64 |  linux-ia64

https://stackoverflow.com/questions/7635013/difference-between-x86-x32-and-x64-architectures

x32 is an ABI for amd64/x86_64 CPUs using 32-bit integers, longs and pointers. The idea is to combine the smaller memory and cache footprint from 32-bit data types with the larger register set of x86_64. (Reference: Debian X32 Port page).