[nsp] Cisco routers: DRAM chips banks used

[Dennis Peng]

Gert Doering [gert at greenie.muc.de] wrote:
> Hi,
> 
> On Mon, Jan 05, 2004 at 11:35:55AM -0800, Dennis Peng wrote:
> > > 2500
> > I think the 2500 only has one bank for system DRAM.
> 
> Correct.  Some of them have 2Mb soldered on-board, though, so a 4 Mb
> 2500 could have 2+2 or 0+4, IIRC...

I think you are right.

> [..]
> > On the 2600, if you have a version of IOS which contains the fix for
> > CSCdv58188 (12.2(11)T and later), you can see the memory configuration
> > in the "show c2600" command.
> [..]
> > If you have the fix for CSCdv58200 (12.3(3) and later), you can see
> > the memory configuration in the "show c3600" command.
> 
> Now that's really cool news :-)
> 
> For the 36xx series with not-so-current IOS versions, there is another 
> way to find out the memory layout - going through IOS memory, finding 
> the location where the boot ROM stores the memory layout and then 
> looking there for the information:
> 
> http://www.cisco.com/warp/customer/63/simm_config_3620_3640.html

Thanks for forwarding the link, I didn't know they made that publicly
available. If you are willing to troll through some hex dumps, I came
up with a similar method to find out the memory configuration on the
2600 if you are running older IOS.

Start by exmaining memory starting at 0x68010100. Here is an example:

c2600#sh mem 0x68010100
68010100: FFF00401 FFE00566 00000081 7F000600  .p...`.f........
                                     ^^^^^^^^
                                      bank 1
68010110: 00000000 00000000 01000081 7F000600  ................
                   ^^^^^^^^          ^^^^^^^^
                    bank 2            bank 3
68010120: 00000000 00000000 40000001 FF000108  ........ at .......
                   ^^^^^^^^
                    bank 4

DIMM 0 is bank 1 + bank 3 and DIMM 1 is bank 2 + bank 4. If bank 1 is
populated but 3 is not, that means it is single bank memory instead of
dual-bank.

These values tell you how much is in each bank:

7FB0XXXX = 4 MB memory
7F70XXXX = 8 MB memory
7F00XXXX = 16 MB memory
7E00XXXX = 32 MB memory

So in the above example, I have 16 MB in bank 1 and bank 3 which means
I have 32 MB dual-banked RAM in DIMM slot 0. Nothing in DIMM slot 1.

> (needs JavaScript to work)
> 
> > > 7206VXR
> > 
> > Right now, there is no equivalent command on the 7200 platform. You
> > can express interest in having this command by opening up a case and
> > having it attached to CSCdv69265. The more interest we can generate,
> > the faster (and more likely) it will be implemented.
> 
> Most of the NPEs take only one SIMM anyway (NPE-225, NPE-400, NPE-G1),
> so on the 7206VXR, this feature won't be as helpful as for the others...

I quickly glanced through the documentation and it looks like the
NPE-175, NPE-225, NSE-1, and NPE-400 have only one slot. The NPE-100,
NPE-150, NPE-200 and NPE-300 have 2 (or more) slots. The NPE-G1 has
two slots, but I think the two always have to match, so it reduces the
possible combinations.

Dennis

> But nevertheless: thanks for implementing such useful stuff!
> 
> gert
> 
> -- 
> USENET is *not* the non-clickable part of WWW!
>                                                            //www.muc.de/~gert/
> Gert Doering - Munich, Germany                             gert at greenie.muc.de
> fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de