Re: How to figure out what machine it came from?

On Sun, 20 Apr 2008, Michael Kraemer wrote:

E.g. if you put mixed 8/32MB parts into a DECstation,
the console happily indicates all of them,
whereas Ultrix will recognize only some of them.

The memory controller on all the DECstation 5000/2x0 systems supports
mixed memory configurations and the REX console will happily support them
as long as there is a module in the slot #0 and it is of the bigger kind.
In such a case in all the slots containing 8MB modules the memory provided
will be replicated four times accross the slot's address space as all the
memory controller can do is to globally select between slot-selects on
32MB and 8MB boundaries and if an 8MB module is decoded with the 32MB
stride the module simply does not decode the upper two bits of the offset
within its slot.

Similarly NVRAM modules are supported by circuitry of all slots in the
/200 and the slot #15 only in the /240 and /260 with the console acting
accordingly.

Now it is up to the operating system whether a given memory configuration
is supported or not. Ultrix I am told can only support contiguous memory
configurations, but otherwise does not really care what the configuration
looks like. Therefore it can support up to one 8MB module immediately
following a contiguous set of 32MB ones. Linux on the other hand supports
arbitrary configurations as I am told NetBSD does. I have no idea about
OSF/1, nor anything else that could have possibly been ported to these
systems.

Maciej
.

Relevant Pages