[Pc_Support] Re: LUNA: How to get SuSE 9.2 to boot w/ 4 GB of RAM onboard -- mem=3584M

[William A. Mahaffey III]

Bryan J. Smith wrote:

>"Bryan J. Smith" <b.j.smith at ieee.org> wrote:
>  
>
>>Append "mem=" to your boot line.
>>    
>>
>
>You can _try_ "mem=3584M", however ...
>
>  
>
>>_Unfortunately_ that does _not_ address the larger issue of
>>attempting to use the _entire_ 4GiB space on a machine that much
>>map _all_ ROM, memory mapped I/O, kernel space and other things
>>under that 4GiB.
>>    
>>
>
>It's very, very, _very_likely_ that without the BIOS option to create
>a "memory hole" at 3.6-4.0GiB, your ROM and memory mapped I/O will
>_not_ be mapped correctly in the system's APIC registers, and you
>will _still_ have issues.
>
>And that's assuming it's not the fact that you're well beyond JEDEC
>PC3200 standards on the DDR400 signaling with 8 banks (4 DIMMs).  ;->
>  
>

Thanks for the detailed response, we are *quite* aware of the 
limitations of 4 GB address space max, minus whatever the kernel/BIOS 
want, we are looking for a bit over 3 GB for the application. Where do I 
put the "mem=3584M" line (in what file, we don't want to have to 
remember it every time we reboot) ? The man pages (at least the default 
ones) are notably sparse on details of GRUB ('apropos grub' only shows 3 
entries, all quite truncated, virtually useless). TIA ....

As an aside/digression, we are also aware of the problems/limitations of 
using a relatively old OS for this box, but the client in this case is 
using predominantly SuSE 9.3 on desktops and a similar vintage SLE on 
their cluster, and we wanted as few problems/compatibility-surprises w/ 
the software we are supposed to deliver as possible :-). Once SuSE 9.2 
was settled on, we deliberately avoided newer hardware (S775 Pentiums, 
for example) over hardware-compatibility concerns w/ the older SuSE. 
*Not* my decision making, BTW, I suggested an Opteron :-) ....

-- 
	William A. Mahaffey III

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	"The M1 Garand is without doubt the finest implement of war
	 ever devised by man."
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