RAM for digital server 5300
Jay Estabrook
jay.estabrook at hp.com
Wed Apr 25 21:22:11 UTC 2007
Simon Tierney wrote:
> Thanks for replying on this elementary hardware question Jay, I think I'll
> risk trying the 512's because W. Bohrer has got them working and I just want
> to beef up the RAM, not max out of the 4Gb limit.
Someone actually has tried it? How many did he use, and how did the
memory get configured?
I don't think you can hurt the machine with them, but I'm quite
surprised that it was bootable with them in it; in fact, frankly
I'm amazed... ;-}
Is it that you can't get the 256MB DIMMs now, and only the 512's
are available? Otherwise, I'd think that two 256's would be cheaper
than 1 512...
Good luck, and please let me know how it works out.
--Jay++
> Thanks,
>
> Simon
>
> ----- Original Message -----
> From: "Jay Estabrook" <jay.estabrook at hp.com>
> To: "Linux on Alpha processors" <axp-list at redhat.com>
> Sent: Wednesday, April 25, 2007 9:14 PM
> Subject: Re: RAM for digital server 5300
>
>
> Simon Tierney wrote:
>> I have one of these machines which has cards to take PC100 ECC SDRAM
>> modules, 1 card for each CPU.
>>
>> The Service and User manuals require replacement RAM modules of 128 Mb
> and
>> 256 Mb (in pairs), but larger modules (512Mb) have become available since
>> these manuals were written.
>>
>> Has anyone any experience adding these larger modules? Will the system be
>> able to address them, or should I stick to 256 modules?
>
> I've no experience trying those 512MB DIMMs, but the docs do say that
> the memory limit is 4GB done by 8 pairs of 256MB DIMMs, so I really
> would NOT recommend trying anything larger. From the docs:
>
> "The rules for addressing memory are as follows:
>
> * A memory pair consists of 2 DIMMs of the same size.
> * Memory pairs in riser cards may be of different sizes.
> * The memory pair in slot 0 must be the largest of all memory
> pairs. Other memory pairs may be as large but none may be
> larger.
> * The physical starting address of each memory pair is N times 512MB
> (2000000) where N is the slot number on the riser card.
> * Memory addresses are contiguous within each module pair.
> * If memory pairs do not completely fill the 512MB space provided,
> memory “holes” occur in the physical address space.
> * Software creates contiguous virtual memory even though physical
> memory may not be contiguous."
>
> So, it's really a hardware limitation in the way that memory DIMM pairs
> are mapped into the physical address space, that tops out at 4MB on the
> 5300.
>
> Sorry.
>
> --Jay++
>
--
Jay A Estabrook HPTC - XC I & B
Hewlett-Packard Company - ZKO1-3/D-B.8 (603) 884-0301
110 Spit Brook Road, Nashua NH 03062 Jay.Estabrook at hp.com
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