[gentoo-user] Advice for 64-bit n00b?

[Stroller <stroller@stellar.eclipse.co.uk>]

Hi there,

A new (to me) server has 64-bit CPUs. By my standards this is a REALLY  
NICE high specification machine (I appears to be 2 x dual-core), but  
in fact it's about 3 years old & is one of the earliest Intel Xeons  
that supports 64-bits / AMD64 / EMT64. I think it is 64-bit Pentium 4,  
rather than Core 2 architecture.

# cat /proc/cpuinfo | head -n 25
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      : Intel(R) Xeon(TM) CPU 3.00GHz
stepping        : 3
cpu MHz         : 2992.346
cache size      : 2048 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 1
apicid          : 0
initial apicid  : 0
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge  
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe  
syscall nx lm constant_tsc pebs bts pni dtes64 monitor ds_cpl cid cx16  
xtpr
bogomips        : 5984.69
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:


I'm a bit confused by the 36-bit address size mentioned there, but I  
assume this is OK. The Gentoo wiki seems to confirm this CPU is 64- 
bit: http://tinyurl.com/klv7gc [1]

Is there anything I need to know about working with 64-bits / AMD64 /  
EMT64, seeing as I've never done so before?

I have started following the Gentoo Linux AMD64 Handbook, because the  
Quick Install Guide is described as "x86". Having untarred the stage I  
am surprised to find a lib32 directory. I thought compatibility with  
32-bit binaries was optional. Or am I misunderstanding? This is going  
to be a headless server & I can't think that it'll need any binary  
packages - possibly the management utility for the RAID controller  
will be distributed as a binary, I'm not sure yet (the hardware RAID  
key was missing when I got this machine ☹)

I'm editing my make.conf and looked at the Gentoo wiki for "Safe  
Cflags" - it says 'CHOST="x86_64-pc-linux-gnu"'. But of course  
(according to make.conf.example) one shouldn't change CHOST on an  
installed system. Will the files in the stage 3 have been compiled  
using this CHOST?

Any pointers would be gratefully appreciated - I'm wondering if  
there's anything you guys all take for granted that I could mess up if  
I don't allow for it early enough in the installation process.

Thanks in advance for any comments,

Stroller.




[1] http://en.gentoo-wiki.com/wiki/Safe_Cflags/Intel#Xeon_w.2FEM64T_.28also_Pentium_4_P6xx_or_Celeron_M_5xx.29