Can 32-bit Linux be installed on 64-bit laptop (and is it a good idea)?

[James Wilkinson]

Reshat Sabiq wrote:
> Can 32-bit Linux be installed on 64-bit laptop (and is it a good idea)?

Yes, and it depends on what you're trying to do.

> From what I remember 64-bit processors still support 32-bit exes,

Yup.
> which means I should be able to run all the 32-bit software,

*Mostly*. You won't be able to run 32-bit kernel modules, and you won't
be able to run 32 bit browser plug-ins unless you install a 32 bit
browser.

> and for that
> software the memory usage will not double. I.e., 256MB RAM for 64-bit box
> running mostly 32-bit software is not like 128MB RAM for 32-bit box. I
> suspect if the OS was 64-bit, then the OS pieces might be consuming twice
> as much memory as on 32-bit box, but I think that XP it is shipped with
> is 32-bit, which means it's not gonna be consuming twice the memory.

Assuming you're talking an x86-64 (AMD or Intel) laptop here...

AMD once quoted that 64 bit code was roughly 10% larger. That figure
varies a lot, but just because a binary can cope with 64 bit addresses
doesn't mean that everything is twice as large. Most of your memory is
taken up by data, not code, 

On the other hand, you may find that if you are running 32 bit and 64
bit binaries simultaneously, then the system has to keep 32 bit and 64
bit equivalents of the same libraries in memory at the same time.

In general, a 64 bit mode install takes more memory and disk space. (For
example, the FC4 install takes 4 CDs in 32 bit mode, but the 64 bit
version has a small fifth CD).

64 bit mode works well, and I'm using it. But it's not the default: more
third-party software comes compiled for 32 bits, and the 64 bit / 32 bit
multi-library install adds some complexity. If you just want a quiet
life, I'd recommend 32 bit mode. It's slower, but not by much: you
probably won't notice it.

Hope this helps,

James.
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