Re: Identifying CPU and current OS

[Greg <curtyshoo@gmail.com>]

On 2025-09-30, Michael Stone <mstone@debian.org> wrote:
> On Tue, Sep 30, 2025 at 04:08:56PM -0000, Greg wrote:
>> In computing, a word is any processor design's natural unit of data. A word is
>> a fixed-sized datum handled as a unit by the instruction set or the hardware of
>> the processor.
>
> It has that definition (among others), one which mapped cleanly to 
> historic processors, but which is much messier when dealing with modern 
> CPUs. E.g., amd64 mostly has 64bit instruction operands and types, but 
> there's also an 80 bit floating point type and with AVX-512 extensions 
> has 512 bit registers and can transfer data to/from memory 512 bits at a 
> time in a single instruction. So is the word size 512? 80? 64? 
> Conversely, if someone confidently says "its word size is 64", what does 
> that tell you/what can you do with that information? If it's a term 
> divorced from practical applications then it's just a historical
> curiosity. If someone has to add a bunch of asterisks and explain away
> functionality that doesn't cleanly fit into the model, how relevant is 
> the model?
>

I think the key word here is *natural* (the machine's general-purpose
integer registers, the ones used for addresses and integer arithmetic,
not the specialized, vector register widths).