Install amd64 over existing i386

Polytropon freebsd at
Mon Mar 16 16:48:28 UTC 2015

On Sun, 15 Mar 2015 12:09:19 -0400 (EDT), Chris Hill wrote:
> Hi list,
> I bought a new machine the other day, and accidentally installed the 
> i386 version of FreeBSD on it even though it has a 64-bit processor.

There is no problem running i386 on an 64 bit processor. I'm
doing this myself here because I need software which works best
with i386 (wine, nvidia-driver), and I don't need support for
larger address spaces because this PC has 2 GB RAM (which is
fully sufficient for what I do).

Do you have actual requirements for using amd64? If not, just
keep using the installation you have.

> It 
> works fine, but I think I'd rather have the "right" version.

As I've said, "right" depends on your requirements:

(a) Need i386-specific software that doesn't run easily on amd64?
    Then i386 is right.

(b) Need amd64-specific software and need to support 4+ GB RAM?
    Then amd64 is right.

(c) Neither (a) or (b) applies? Use what you have, stop worrying! :-)

Keep in mind that just because the CPU is 64 bit, this does not
limit you in choices. You can run i386 _or_ amd64 on a 64 bit CPU.
Only amd64 _requires_ a 64 bit CPU (and this _is_ an actual
requirement, by the software, not by the hardware).

> So, two 
> questions:
> 1. Is it even worth worrying about at this point?

This depends on what software you want to use and what hardware
you need to support. Answer those questions first, and you'll
know if you have to worry. :-)

> 2. Can I just install amd64 without destroying existing filesystems and 
> files? I realize I'll have to reinstall my ports, but that's OK.

If you have already configured stuff on the machine you want to
keep using, copy /etc and /usr/local/etc. You can probably use
that with the new version.

However, as you plan a new install, you should clean the file
systems first. The easiest way to do this is newfs. It's fast
and sufficient. Destroying remaining files is a good idea before
you start installing a new OS; "copying it over" just doesn't
sound clean and correct. :-)

As you said, you'll have to reinstall your ports afterwards, so
not having any "garbage" around (from the old OS installation)
is an advantage.

> More info below. Yes, the CMOS clock was set incorrectly when I did the 
> install.
> $ uname -a
> FreeBSD 10.1-RELEASE FreeBSD 10.1-RELEASE #0 
> r274401: Tue Nov 11 22:51:51 UTC 2014 
> root at  i386
> Relevant part of dmesg:
> CPU: Intel(R) Core(TM)2 Duo CPU     E8500  @ 3.16GHz (3158.81-MHz 686-class CPU)
>    Origin = "GenuineIntel"  Id = 0x1067a  Family = 0x6  Model = 0x17  Stepping = 10
>    Features2=0x408e3fd<SSE3,DTES64,MON,DS_CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,SSE4.1,XSAVE>
>    AMD Features=0x20100000<NX,LM>
>    AMD Features2=0x1<LAHF>
>    TSC: P-state invariant, performance statistics

This hardware will run i386 just fine. I have this:

CPU: Intel(R) Core(TM)2 CPU          4300  @ 1.80GHz (1799.82-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x6f2  Family = 6  Model = f  Stepping = 2
  AMD Features=0x20000000<LM>
  AMD Features2=0x1<LAHF>
  TSC: P-state invariant
real memory  = 2147483648 (2048 MB)
avail memory = 2081521664 (1985 MB)

How much RAM do you have? Allowing the access to more RAM could
be somthing you'll need amd64 for.

For comparison, I'm running this:

	% uname -m

There's nothing in amd64 that _I_ need.

Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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